Induction of Giardia spp. infection and biochemical profiles in rats

Induction of Giardia spp. infection and biochemical profiles in rats | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Induction of Giardia spp. infection and biochemical profiles in rats reeda, asmaa This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9226597/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract The present study investigated the metabolic and hepatic effects of experimental Giardia infection in male rats over a four-week post-infection period. Results demonstrated that Giardia infection significantly disrupted glucose homeostasis, as evidenced by a progressive and time-dependent elevation in serum glucose levels. Infected rats exhibited markedly higher glucose concentrations compared with controls, reaching a peak of 472.40 ± 200.86 mg/dL at four weeks post-infection, indicating impaired intestinal absorption and dysregulated glucose metabolism. Concurrently, serum insulin levels were significantly reduced in infected rats, with the highest post-infection value (2.543 ± 0.5431) remaining lower than the control group. Assessment of insulin resistance using the HOMA-IR index revealed a notable increase in infected groups (59.49 ± 61.73), accompanied by a significant decline in insulin sensitivity (0.345 ± 0.132). These findings suggest that Giardia infection promotes insulin resistance and disrupts systemic glucose regulation, likely through inflammatory mechanisms and alterations in gut epithelial function. levels increased progressively over the four-week period, reaching 180.00 ± 75.54 U/L and 492.45 ± 389.57 U/L, respectively, reflecting hepatocellular stress or damage induced by systemic inflammatory responses associated with intestinal infection. In contrast, serum albumin concentrations were consistently higher in infected rats compared with controls (up to 4.48 ± 0.303 g/dL), though these changes did not reach statistical significance, potentially indicating adaptive hepatic protein synthesis in response to infection. Overall, these results demonstrate that Giardia infection exerts profound systemic metabolic and hepatic effects, including hyperglycemia, hypoinsulinemia, increased insulin resistance, and elevated liver enzymes. The findings highlight the broader physiological impact of intestinal parasitic infections and underscore the need to consider their metabolic consequences in both experimental models and clinical settings. Parasitology Giardia Lamblia Intestinal parasite insulin resistance liver enzymes glucose concentrations Introduction Giardia is a flagellated intestinal protozoan parasite that infects humans and animals worldwide, including Iraq [ 1 , 2 ]. Infection occurs primarily through the ingestion of food or water contaminated with the cysts of the parasite, leading to giardiasis [ 3 , 4 ]. The parasite colonizes the upper part of the small intestine, where it adheres to the intestinal mucosa and causes a range of gastrointestinal disturbances These disturbances are mainly characterized by malabsorption of disaccharides, fats, and fat-soluble vitamins, which negatively affects metabolic processes and energy production [ 5 ]. Giardia infection has both direct and indirect effects on the host. The parasite primarily infects the small intestine, particularly in children, leading to malnutrition and, in severe cases, growth retardation, especially in developing countries [ 6 ]. One of the most common routes of infection is the ingestion of cyst-contaminated water, as the parasite is frequently found in lakes, ponds, marshes, and water streams [ 7 ]. Although the relationship between Giardia infection and diabetes mellitus is not considered a direct causal one, several studies suggest that giardiasis may influence glucose and insulin metabolism, as well as alter albumin levels in the body. These effects are attributed to the parasite-induced damage to intestinal epithelial cells and disruption of nutrient absorption mechanisms [ 8 ].Accumulating evidence indicates that Giardia infection, particularly chronic infection, affects the host immune system and the intestinal environment (gut microbiome). Such alterations may subsequently lead to changes in glucose and lipid metabolism [ 9 ]. Furthermore, Giardia infection has been shown to modify the expression of genes associated with glucose metabolism and cellular metabolic homeostasis in intestinal epithelial cells [ 1 ]. Malabsorption of sodium and glucose has been associated with a reduction in the number of villous epithelial cells in the intestine and increased intestinal barrier permeability, which represents a key pathogenic mechanism underlying diarrhea in giardiasis [ 10 ]. Moreover, certain intestinal parasites, including Giardia lamblia, induce the production of reactive oxygen species, which damage cellular components such as proteins, lipids, and nucleic acids. This oxidative stress triggers immune responses involving further generation of free radicals [ 11 ]. Accordingly, the current study aims to evaluate the effect of giardiasis on blood sugar and insulin levels and its relationship to insulin resistance and sensitivity experimentally in rats. Materials and methods 2.1 Experimental Design: This experiment were designed to investigate the effect of the intensity of experimental Giardia infection in rats on serum glucose and insulin levels, as well as on insulin sensitivity and resistance. The current study included 21 male Swiss albino rats, which were divided into two groups. The first group consisted of 15 rats that were experimentally infected with Giardia , Which were orally inoculated with Giardia Lamblia cysts using a gavage tube while the second group 6 male as a control group uninfected rats. The rats were sacrificed and blood samples were collected at 2, 3, and 4 weeks after experimental infection (Including 5 infected animals and 2 control animals). 2.2 Sample collection and source: Stool samples were collected from patients suffering of a symptomatic abdominal pain which came to the Al-Salam Teaching Hospital in Mosul city in the northern of Iraq ( between longitudes \(\:42^\circ\:\:56´-43^\circ\:\:22´\) and latitudes \(\:36^\circ\:\:16´-36^\circ\:\:30\) ), during the month of Oct. The samples were kept in clean and sterile containers until the samples arrived to laboratory at College of Education for Women, to be used for parasite isolation. 2.3 Microscopic examination: A microscopic examination was carried out to confirm the presence of the parasite in stool sample by using the saline sedimentation method, as described by Ritchie et al. [ 12 ], and examined using a light microscope with 100× magnification. 2.4 Parasite isolation and Preparation of parasite dose: In order to isolate Giardia cysts were isolated from stool samples, the samples were centrifuged at 2000 rpm for 5 minutes multiple times. Parasites were identified microscopically using Giemsa stain and examined under a light microscope. To Prepared dose, Cysts were counted and a dose of 150 cysts per animal was used according to Craft [ 13 ]. 2.5 Laboratory animals : Study were used Swiss albino rats, aged 6–8 weeks and weighing between 175–200 grams, Experimental animals were obtained from the Animal House of the College of Education for Women, [University of Mosul]. All animals were maintained under standard laboratory conditions with controlled temperature, humidity, and a 12-hour light/dark cycle, with free access to food and water. The rats were orally inoculated with Giardia cysts using a gavage tube, with dose containing approximately 150 cysts. After that stool samples of rat microscopic examination daily for infection. Blood samples were taken from heart of rats and collected in test tubes containing gel without anticoagulant at 2, 3, and 4 weeks P.I (post infection). The blood sample tubes were centrifuged at a speed of 3000 xg for 15 minutes. The serum was subsequently preserved at -20°C for biochemical examination [ 14 , 15 ]. At the designated experimental time points, rats were humanely euthanised in accordance with institutional ethical guidelines for animal care and use. Animals were first anaesthetised using ketamine (80 mg/kg) and xylazine (10 mg/kg) administered via intraperitoneal injection to ensure deep anaesthesia and loss of consciousness. After confirmation of anaesthetic depth, euthanasia was performed by cardiac puncture followed by exsanguination. This method was selected to minimize pain and distress and to obtain adequate blood samples for biochemical analysis. 2.6 Laboratory examination : 2.6.1 Measurement of glucose in serum Quantitative determination of serum glucose by the enzymatic colorimetric method. Kit from (Giesse-Italy) was used, and the procedure was automatically performed by the chemistry analyzer device (Smart-120, USA). 2.6.2 Measurement of insulin in serum : Rat Insulin (INS) ELISA Kit (Shidealtech-China. Item No.: ADL-ELRT00483). The double antibody sandwich method was used. 2.6.3. Homeostatic model assessment for insulin resistance (HOMA-IR) : Insulin resistance was assessed by the HOMA-IR calculated after fasting rats for 12 h as: • HOMA-IR=Fasting insulin (µU/ml) × Fasting glucose (mmol/l) / 22.5. [ 16 , 17 ].Higher HOMA-IR values are indicative of insulin resistance. 2.6.4. QUICKI (the quantitative insulin-sensitivity check) QUICKI was used to assess insulin resistance: QUICKI = 1/ (log fating insulin (µU/ml) + log fasting glucose (mmol/L)). [ 16 , 17 ].A decrease in QUICKI values indicates insulin resistance. 2.7. Statistical analysis: Statistical analysis was conducted using SPSS software. Differences among groups were analyzed using one-way analysis of variance (One-Way ANOVA). 2.8 Ethical approval : Ethical approval was obtained from the Scientific and Ethical Research Committee at Nineveh Health Directorate (Approval No. 271) on 3/9/2025 for Research Project No. 2025169. All ethical standards were strictly followed for the purpose of conducting this scientific study. The study was carried out in accordance with the Declaration of Helsinki. Ethical approval was obtained from the Ethics Committee of [Department of Biology, College of Education for Girls]. Ethical approval for this study was obtained from the Institutional Animal Care and Use Committee (IACUC) / Institutional Review Board (IRB) of [College of Education for Girls, University of Mosul, Mosul, Iraq, Department of Biology]. All animal procedures were performed in accordance with institutional guidelines and BioMed Central policies for research involving animal. The document is available upon request . 2.9 Ethics Approval and Consent to Participate : The need for informed consent was waived by the Institutional Review Board (IRB) of [the Scientific and Ethical Research Committee at Nineveh Health Directorate (Approval No. 271) on 3/9/2025 for Research Project No. 2025169] in accordance with national regulation" in the manuscript. Results 3.1 Serum Glucose Levels: Evaluation of serum glucose concentrations demonstrated that Giardia infection induced a statistically significant elevation in glucose levels across all infected groups compared with the control group. The increase in glucose concentration was time-dependent, with a progressive rise observed following infection and peak reaching 472.86 ± 200.40 mg/dL , as shown in Table (1). Table (1): Effect of Giardia infection on serum glucose levels in male rats at different post-infection intervals *Serum glucose levels showed a clear increase over time compared with the control group, with all values approaching or exceeding the statistical significance level (p ≤ 0.05). 3.2 Serum Insulin levels: The present results demonstrated a significant decrease in serum insulin levels in infected rats compared with the control group, as presented in Table (2). The highest insulin level was observed during the fourth week post-infection, with a value of 2.543 ± 0.5431 , yet it remained significantly lower than that of the control group. 3.3 Assessment of Insulin Resistance and sensitivity: HOMA-IR index in all groups had different values compared with control group, HOMA-IR index is calculated using fasting plasma insulin and glucose levels. Using the previously described formula outlined in the Materials and Methods section (Section 2.6.3), a significant increase in insulin resistance was observed in the infected groups, reaching 59.49 ± 61.729 compared with the control group. Conversely, insulin sensitivity showed a marked decrease, declining to 0.345 ± 0.132 in comparison with the control group Table (2). Table (2): Effect of Giardia infection on insulin-related parameters post infection *A significant increase in insulin resistance was noted, approaching statistical significance (p ≈ 0.05). *Insulin sensitivity showed a significant increase at week 2 (p = 0.01), with a lower increase at week 3 (p = 0.01) and a slight but near-significant increase at week 4 (p = 0.086). 3.4 The effect of Giardia infection on ALT (GPT) and AST (GOT) levels: According to r esults, ALT (GPT) and AST (GOT) levels in serum showed a significant increase all over the weeks post infection compared with control group, the results demonstrated a progressive increase with the advancement of the experimental infection period in rats, and the increase was statistically significant at the 0.05 level. The highest of ALT (GPT) value was observed after the fourth week, reaching 180.00 ± 75.54. Similarly, the same trend was observed in AST (GOT) levels . Table (3): Effect of Giardia infection on ALT (GPT) levels at different post-infection intervals *Significant differences were observed between time intervals (p-values ranged from 0.043 to 0.067). All values were close to the statistical significance level (p = 0.05) Table (4): Effect of Giardia infection on AST (GOT) levels in male rats at different post-infection intervals *Values at 4 weeks (p = 0.054) were close to the statistical significance level, showing a clear and gradual increase over time. As shown in Table (5), serum albumin levels in male rats with Giardia -infected, were consistently higher than those in the control group at all post-infection intervals. Albumin concentrations increased to 4.48 ± 0.303 g/dL at two weeks post-infection, followed by 4.30 ± 0.182 g/dL at three weeks and 4.40 ± 0.212 g/dL at four weeks, compared with a constant control value of 2.17 g/dL. Although these increases did not reach statistical significance. Table (5): Effect of Giardia infection on serum albumin levels in male rats at different post-infection intervals *Differences were close to statistical significance (p-values ranged from 0.065 to 0.08). Discussion The present study demonstrated that experimental Giardia infection significantly alters glucose metabolism in male rats. Serum glucose levels showed a progressive and time-dependent increase following infection, reaching a peak of 472.40 ± 200.86 mg/dL at four weeks post-infection (Table 1). These findings are consistent with previous reports indicating that Giardia infection can induce hyperglycemia by disrupting normal intestinal function and nutrient absorptio[18,9].The elevated glucose levels observed may result from impaired glucose uptake in enterocytes, as Giardia trophozoites adhere to the intestinal epithelium and interfere with SGLT1-mediated glucose transport [8]. Furthermore, the observed decrease in serum insulin levels (Table 2) suggests that infection may impair pancreatic β-cell function or enhance insulin clearance, contributing to relative insulin deficiency. The highest insulin levels recorded at four weeks post-infection (2.543 ± 0.5431) remained significantly lower than those of the control group, indicating a disruption in insulin homeostasis. These findings align with prior studies demonstrating that Giardia infection can modulate host insulin secretion, potentially through inflammatory cytokine-mediated β-cell dysfunction [1,6]. Assessment of insulin resistance using the HOMA-IR index revealed a marked increase in infected rats, reaching 59.49 ± 61.729, while insulin sensitivity decreased to 0.345 ± 0.132 compared with controls (Table 2). These changes indicate that Giardia infection promotes insulin resistance, likely via systemic and local inflammatory responses as well as alterations in gut microbiota composition [9]. Chronic Giardia infection has been shown to induce a pro-inflammatory environment in the intestine, which can impair insulin signaling pathways in peripheral tissues, thereby increasing insulin resistance [19]. The progressive nature of these metabolic disturbances suggests a cumulative effect of prolonged infection. Early disruptions in glucose absorption, coupled with inflammatory-mediated insulin dysregulation, may collectively contribute to the observed hyperglycemia and reduced insulin sensitivity. Such findings highlight the systemic metabolic consequences of intestinal parasitic infections beyond local gastrointestinal pathology [20].Overall, these results reinforce the concept that Giardia infection is not limited to gastrointestinal manifestations but can also affect host metabolic regulation, including glucose homeostasis, insulin secretion, and insulin sensitivity. These observations have implications for understanding parasite-induced metabolic dysregulation, particularly in populations with high prevalence of giardiasis. According to r esults, the present study demonstrated that the effect of Giardia infection on ALT, AST, and Albumin levels in the experimental Giardia infection in male rats induced significant alterations in liver function biomarkers. Serum ALT (GPT) and AST (GOT) levels showed a progressive and time-dependent increase throughout the post-infection period, with the highest ALT value recorded at four weeks post-infection ( 180.00 ± 75.54 U/L ) and a similar trend observed for AST ( 492.45 ± 389.57 U/L ) (Tables 3 and 4). These elevations were statistically significant or approached the threshold for significance (p = 0.05), indicating hepatocellular stress or damage following Giardia infection. The observed increase in transaminase levels may reflect direct or indirect hepatic effects induced by the parasite. Although Giardia primarily colonizes the small intestine, systemic effects mediated by inflammatory responses, oxidative stress, and gut-liver axis interactions can result in liver enzyme elevation. Similar findings were reported by [6, 9], who observed that intestinal parasitic infections could induce oxidative and inflammatory-mediated hepatocellular injury. The gradual increase over time suggests that prolonged infection exacerbates hepatic stress, possibly due to chronic intestinal inflammation, malabsorption of nutrients, and systemic immune activation. Furthermore, the present study revealed an increase in serum albumin concentrations in infected rats compared with controls (Table 5). Albumin levels were consistently higher across all post-infection intervals, reaching 4.48 ± 0.303 g/dL at two weeks post-infection. Although these differences did not reach statistical significance (p-values 0.065–0.08), the trend suggests that Giardia infection may alter protein metabolism or induce compensatory hepatic protein synthesis. Previous studies have shown that parasitic infections can disrupt the balance between protein synthesis and degradation, affecting plasma protein levels, including albumin [18, 19] Conclusion These findings highlight that Giardia infection can exert systemic metabolic effects beyond the intestinal tract. The observed elevations in liver enzymes indicate hepatocellular stress, likely mediated by inflammation and oxidative mechanisms, while the trend toward increased albumin levels may reflect adaptive hepatic responses to maintain plasma protein homeostasis. Such alterations underscore the broader metabolic consequences of intestinal parasitic infections, particularly in chronic or high-intensity infections. Declarations 6. Acknowledgments: We extend our sincere thanks and appreciation to the staff of the Department of Life Sciences, College of Education for Women, University of Mosul. 7. Conflict of Interest: The authors declare no conflict of interest regarding this study. 8.Funding : This study did not receive any specific financial support from any public or private entity. 9. Declarations Statement : The datasets generated and analysed during this study are included in this published article. Data Availability The datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request. 10 . Data Availability: Additional data are available from the corresponding author upon reasonable request. 11. Consent for Publication : Not Applicable in this section, due to the use of anonymized samples. References Demichele E, Sosnowski O, Flood D, Allain T, Buret AG. Giardia duodenalis stabilizes HIF-1α and induces glycolytic alterations in intestinal epithelial cells. Sci Rep. 2025; 15:28852. Majeed HA. Study the relationship between giardiasis incidence and selected epidemiological factors in Baghdad City. Al-Mustansiriyah J Sci. 2019; 29(3):35–44. Ismail I, Hakeem K, Ali A. Antioxidation potential of date palm fruits and their role in oxidative stress–related diseases. J Food Sci Technol. 2022; 59(7):1802–1811. Al-Daoody AAK, Ismail SM, Ezadin ZY, Kakl D. Prevalence of Giardia lamblia among residents of Hawler, Soran, and Chamchamal cities, northern Iraq. Pak-Euro J Med Life Sci. 2020; 3(2):28–36. Solaymani-Mohammadi S, Eckmann L, Singer SM. Interleukin-21 in inflammation and immunity during parasitic diseases. Front Immunol. 2019; 9:401. doi:10.3389/fimmu.2018.00401. Solaymani-Mohammadi S. Mucosal defense against Giardia at the intestinal epithelial cell interface. Front Immunol. 2022; 13:817468. Mayo Clinic. Giardia infection: Symptoms and causes. Rochester (MN): Mayo Foundation for Medical Education and Research; 2023 [cited 2025 Jan 10]. Available from: https://www.mayoclinic.org Yu LCH, Huang CY, Kuo WT, Sayer H, Turner JR, Buret AG. SGLT-1–mediated glucose uptake protects human intestinal epithelial cells against Giardia duodenalis -induced apoptosis. Int J Parasitol. 2008; 38(8–9):923–934. Klimczak S, Packi K, Rudek A, Wenclewska S, Kurowski M, Kurczabinska D, et al. The influence of Giardia lamblia on host glucose and lipid metabolism. Metabolites. 2024; 25(16):8627. Doi: 10.3390/metabo25168627. Amorim RM, Oliveira DR, Freitas SE, Viana MP, Borges EL. Effect of giardiasis combined with low-protein diet on intestinal absorption of glucose and electrolytes in gerbils. Exp Parasitol. 2012; 131(4):448–451. Slevaney A, Carter J, Morrison L. Oxidative stress and immune responses during intestinal protozoan infections. Parasite Immunol. 2024; 46(3):e12987. Ritchie LS, Lin S, Moon AP, Frick LP, Williams JE, Asakura S, Hishinuma Y. The possible effects of pH and specific gravity on the ether-sedimentation procedure in concentrating eggs and cysts. Am J Trop Med Hyg. 1960; 9(5):444–449. Craft JC. Experimental infection with Giardia lamblia in rats. J Infect Dis. 1982; 145(4):495–498. doi:10.1093/infdis/145.4.495. Parasuraman S, Balamurugan S, Christapher PV, Petchi RR, Yeng WY, Sujithra J, Vijaya C. Evaluation of antidiabetic and antihyperlipidemic effects of Ocimum tenuiflorum . Pharmacogn Res. 2015; 7(2):156–162. doi:10.4103/0974-8490.157997. Greenfield EA. Sampling and preparation of mouse and rat serum. Cold Spring Harb Protoc. 2017; 2017(11):pdb.prot100271. doi:10.1101/pdb.prot100271. Gutch M, Kumar S, Razi SM, Gupta KK, Gupta A. Assessment of insulin sensitivity/resistance. Indian J Endocrinol Metab. 2015; 19(1):160–164. doi:10.4103/2230-8210.146874. Minh HV, Tien HA, Sinh CT, Thang DC, Chen CH, Tay JC, et al. Assessment of preferred methods to measure insulin resistance in Asian patients with hypertension. J Clin Hypertens (Greenwich). 2021; 23(3):529–537. doi:10.1111/jch.14155. Gil FF, Moreira de Mendes G, Aquino Teixeira MC, Oliveira DR, Cruz RE, Santos JFG, et al. Giardia lamblia infection induces changes in the biochemical profile of gerbils ( Meriones unguiculatus ). J Infect Dev Ctries. 2025; 19(6):962–970. Barash NR, Maloney JG, Singer SM, Dawson SC. Giardia alters commensal microbial diversity throughout the murine gut. Infect Immun. 2017; 85(6):e00023-17. W u J, He C, Bu J, Luo Y, Yang S, Ye C, Yu S, He B, Yin Y, and Yang X. Betaine attenuates LPS-induced downregulation of occludin and claudin-1 and restores intestinal barrier function. BMC Vet Res. 2020; 16(1):75. Doi: 10.1186/s12917-020-02298-3. Tables Tables 1 to 5 are available in the supplementary files section Additional Declarations The authors declare no competing interests. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9226597","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":612228295,"identity":"7f7d0e64-8cfc-4088-805e-277042b47e1f","order_by":0,"name":"reeda","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA5UlEQVRIiWNgGAWjYJACaRDBD+XIALEBGBHUItkA4fAQr8XgAIoWPMC8vfng7cIcGznjG8lHN3z4c5iHgb15mwRDgTVOLTJnjiVbz9yWZmx2Iy3t5sw2oBaeY2USDAbpOLVISOSYSfNuO5y47UaO2W3eBqAWoAhQy2HcWuTffwNr2TwDqIUH5DD5NwS0SPCwgbVskABpYQPZwkNAC0+asTUv0C8SZ56B/JLOw8aTVmyRgM8v7Icf3ubdZiPH35587MaHP9Zy/OyHN4IYOLVgAjYQkcDATIIWKCBDyygYBaNgFAxXAADlKEr8/WAgAgAAAABJRU5ErkJggg==","orcid":"","institution":"university of Mosul","correspondingAuthor":true,"prefix":"","firstName":"","middleName":"","lastName":"reeda","suffix":""},{"id":612228296,"identity":"9ce1700d-07b7-430b-98c4-2d6c7154b2a0","order_by":1,"name":"asmaa","email":"","orcid":"","institution":"suaan","correspondingAuthor":false,"prefix":"","firstName":"","middleName":"","lastName":"asmaa","suffix":""}],"badges":[],"createdAt":"2026-03-25 19:20:27","currentVersionCode":1,"declarations":{"humanSubjects":false,"vertebrateSubjects":true,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":true},"doi":"10.21203/rs.3.rs-9226597/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9226597/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":105567226,"identity":"369a6136-1a50-44dd-a4dd-3c20e70d29c6","added_by":"auto","created_at":"2026-03-27 12:58:42","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1379543,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9226597/v1/4337e429-9446-4ebf-a463-c5692e32c99c.pdf"},{"id":105526641,"identity":"1e844599-89c5-4dc3-a7e2-71689d547903","added_by":"auto","created_at":"2026-03-27 04:26:13","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":18394,"visible":true,"origin":"","legend":"","description":"","filename":"Tables.docx","url":"https://assets-eu.researchsquare.com/files/rs-9226597/v1/c340b01c2948429949254872.docx"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003e\u003cstrong\u003eInduction of \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eGiardia\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003espp.\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e infection and biochemical profiles in rats\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eGiardia is a flagellated intestinal protozoan parasite that infects humans and animals worldwide, including Iraq [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Infection occurs primarily through the ingestion of food or water contaminated with the cysts of the parasite, leading to giardiasis [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. The parasite colonizes the upper part of the small intestine, where it adheres to the intestinal mucosa and causes a range of gastrointestinal disturbances These disturbances are mainly characterized by malabsorption of disaccharides, fats, and fat-soluble vitamins, which negatively affects metabolic processes and energy production [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eGiardia infection has both direct and indirect effects on the host. The parasite primarily infects the small intestine, particularly in children, leading to malnutrition and, in severe cases, growth retardation, especially in developing countries [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. One of the most common routes of infection is the ingestion of cyst-contaminated water, as the parasite is frequently found in lakes, ponds, marshes, and water streams [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Although the relationship between Giardia infection and diabetes mellitus is not considered a direct causal one, several studies suggest that giardiasis may influence glucose and insulin metabolism, as well as alter albumin levels in the body. These effects are attributed to the parasite-induced damage to intestinal epithelial cells and disruption of nutrient absorption mechanisms [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].Accumulating evidence indicates that Giardia infection, particularly chronic infection, affects the host immune system and the intestinal environment (gut microbiome). Such alterations may subsequently lead to changes in glucose and lipid metabolism [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Furthermore, Giardia infection has been shown to modify the expression of genes associated with glucose metabolism and cellular metabolic homeostasis in intestinal epithelial cells [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eMalabsorption of sodium and glucose has been associated with a reduction in the number of villous epithelial cells in the intestine and increased intestinal barrier permeability, which represents a key pathogenic mechanism underlying diarrhea in giardiasis [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Moreover, certain intestinal parasites, including Giardia lamblia, induce the production of reactive oxygen species, which damage cellular components such as proteins, lipids, and nucleic acids. This oxidative stress triggers immune responses involving further generation of free radicals [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAccordingly, the current study aims to evaluate the effect of giardiasis on blood sugar and insulin levels and its relationship to insulin resistance and sensitivity experimentally in rats.\u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n \u003ch2\u003e2.1 Experimental Design:\u003c/h2\u003e\n \u003cp\u003eThis experiment were designed to investigate the effect of the intensity of experimental \u003cem\u003eGiardia\u003c/em\u003e infection in rats on serum glucose and insulin levels, as well as on insulin sensitivity and resistance. The current study included 21 male Swiss albino rats, which were divided into two groups. The first group consisted of 15 rats that were experimentally infected with \u003cem\u003eGiardia\u003c/em\u003e, Which were orally inoculated with \u003cem\u003eGiardia Lamblia\u003c/em\u003e cysts using a gavage tube while the second group 6 male as a control group uninfected rats. The rats were sacrificed and blood samples were collected at 2, 3, and 4 weeks after experimental infection (Including 5 infected animals and 2 control animals).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\n \u003ch2\u003e2.2 Sample collection and source:\u003c/h2\u003e\n \u003cp\u003eStool samples were collected from patients suffering of a symptomatic abdominal pain which came to the Al-Salam Teaching Hospital in Mosul city in the northern of Iraq ( between longitudes \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:42^\\circ\\:\\:56\u0026acute;-43^\\circ\\:\\:22\u0026acute;\\)\u003c/span\u003e\u003c/span\u003e and latitudes\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:36^\\circ\\:\\:16\u0026acute;-36^\\circ\\:\\:30\\)\u003c/span\u003e\u003c/span\u003e), during the month of Oct. The samples were kept in clean and sterile containers until the samples arrived to laboratory at College of Education for Women, to be used for parasite isolation.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\n \u003ch2\u003e2.3 Microscopic examination:\u003c/h2\u003e\n \u003cp\u003eA microscopic examination was carried out to confirm the presence of the parasite in stool sample by using the saline sedimentation method, as described by Ritchie et al. [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], and examined using a light microscope with 100\u0026times; magnification.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\n \u003ch2\u003e2.4 Parasite isolation and Preparation of parasite dose:\u003c/h2\u003e\n \u003cp\u003eIn order to isolate \u003cem\u003eGiardia\u003c/em\u003e cysts were isolated from stool samples, the samples were centrifuged at 2000 rpm for 5 minutes multiple times. Parasites were identified microscopically using Giemsa stain and examined under a light microscope. To Prepared dose, Cysts were counted and a dose of 150 cysts per animal was used according to Craft [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\n \u003ch2\u003e\u003cstrong\u003e2.5 Laboratory animals\u003c/strong\u003e:\u003c/h2\u003e\n \u003cp\u003eStudy were used Swiss albino rats, aged 6\u0026ndash;8 weeks and weighing between 175\u0026ndash;200 grams, Experimental animals were obtained from the Animal House of the College of Education for Women, [University of Mosul]. All animals were maintained under standard laboratory conditions with controlled temperature, humidity, and a 12-hour light/dark cycle, with free access to food and water. The rats were orally inoculated with \u003cem\u003eGiardia\u003c/em\u003e cysts using a gavage tube, with dose containing approximately 150 cysts. After that stool samples of rat microscopic examination daily for infection. Blood samples were taken from heart of rats and collected in test tubes containing gel without anticoagulant at 2, 3, and 4 weeks P.I (post infection). The blood sample tubes were centrifuged at a speed of 3000 xg for 15 minutes. The serum was subsequently preserved at -20\u0026deg;C for biochemical examination [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. At the designated experimental time points, rats were humanely euthanised in accordance with institutional ethical guidelines for animal care and use. Animals were first anaesthetised using ketamine (80 mg/kg) and xylazine (10 mg/kg) administered via intraperitoneal injection to ensure deep anaesthesia and loss of consciousness. After confirmation of anaesthetic depth, euthanasia was performed by cardiac puncture followed by exsanguination. This method was selected to minimize pain and distress and to obtain adequate blood samples for biochemical analysis.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\n \u003ch2\u003e\u003cstrong\u003e2.6 Laboratory examination\u003c/strong\u003e:\u003c/h2\u003e\n \u003cdiv id=\"Sec9\" class=\"Section3\"\u003e\n \u003ch2\u003e\u003cstrong\u003e2.6.1 Measurement of glucose in serum\u003c/strong\u003e\u003c/h2\u003e\n \u003cp\u003eQuantitative determination of serum glucose by the enzymatic colorimetric method. Kit from (Giesse-Italy) was used, and the procedure was automatically performed by the chemistry analyzer device (Smart-120, USA).\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec10\" class=\"Section3\"\u003e\n \u003ch2\u003e\u003cstrong\u003e2.6.2 Measurement of insulin in serum\u003c/strong\u003e:\u003c/h2\u003e\n \u003cp\u003eRat Insulin (INS) ELISA Kit (Shidealtech-China. Item No.: ADL-ELRT00483). The double antibody sandwich method was used.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec11\" class=\"Section3\"\u003e\n \u003ch2\u003e\u003cstrong\u003e2.6.3. Homeostatic model assessment for insulin resistance\u003c/strong\u003e (HOMA-IR) :\u003c/h2\u003e\n \u003cp\u003eInsulin resistance was assessed by the HOMA-IR calculated after fasting rats for 12 h as:\u003c/p\u003e\n \u003cp\u003e\u0026bull; HOMA-IR=Fasting insulin (\u0026micro;U/ml) \u0026times; Fasting glucose (mmol/l) / 22.5.\u003c/p\u003e\n \u003cp\u003e[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].Higher HOMA-IR values are indicative of insulin resistance.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec12\" class=\"Section3\"\u003e\n \u003ch2\u003e2.6.4. QUICKI (the quantitative insulin-sensitivity check)\u003c/h2\u003e\n \u003cp\u003eQUICKI was used to assess insulin resistance:\u003c/p\u003e\n \u003cp\u003eQUICKI\u0026thinsp;=\u0026thinsp;1/ (log fating insulin (\u0026micro;U/ml)\u0026thinsp;+\u0026thinsp;log fasting glucose (mmol/L)).\u003c/p\u003e\n \u003cp\u003e[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].A decrease in QUICKI values indicates insulin resistance.\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\n \u003ch2\u003e2.7. Statistical analysis:\u003c/h2\u003e\n \u003cp\u003eStatistical analysis was conducted using SPSS software. Differences among groups were analyzed using one-way analysis of variance (One-Way ANOVA).\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e2.8 Ethical approval :\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;Ethical approval was obtained from the Scientific and Ethical Research Committee at Nineveh Health Directorate (Approval No. 271) on 3/9/2025 for Research Project No. 2025169. All ethical standards were strictly followed for the purpose of conducting this scientific study. The study was carried out in accordance with the Declaration of Helsinki. Ethical approval was obtained from the Ethics Committee of [Department of Biology, College of Education for Girls].\u003cbr\u003eEthical approval for this study was obtained from the Institutional Animal Care and Use Committee (IACUC) / Institutional Review Board (IRB) of [College of Education for Girls, University of Mosul, Mosul, Iraq, Department of Biology]. All animal procedures were performed in accordance with institutional guidelines and BioMed Central policies for research involving animal. The document is available upon request\u003cspan dir=\"RTL\"\u003e.\u003c/span\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e2.9 Ethics Approval and Consent to Participate :\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eThe need for informed consent was waived by the Institutional Review Board (IRB) of [the Scientific and Ethical Research Committee at Nineveh Health Directorate (Approval No. 271) on 3/9/2025 for Research Project No. 2025169] in accordance with national regulation\u0026quot; in the manuscript.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Results","content":"\u003ch4\u003e\u003cstrong\u003e3.1 Serum Glucose Levels:\u003c/strong\u003e\u003c/h4\u003e\n\u003cp\u003e\u0026nbsp;Evaluation of serum glucose concentrations demonstrated that\u0026nbsp;\u003cem\u003eGiardia\u003c/em\u003e infection induced a statistically significant elevation in glucose levels across all infected groups compared with the control group. The increase in glucose concentration was time-dependent, with a progressive rise observed following infection and peak reaching\u0026nbsp;\u003cstrong\u003e472.86 \u0026plusmn; 200.40 mg/dL\u003c/strong\u003e, as shown in Table (1).\u003c/p\u003e\n\u003cp\u003eTable (1): Effect of \u003cem\u003eGiardia\u003c/em\u003e infection on serum glucose levels in male rats at different post-infection intervals\u003c/p\u003e\n\u003cp\u003e*Serum glucose levels showed a clear increase over time compared with the control group, with all values approaching or exceeding the statistical significance level (p \u0026le; 0.05).\u003c/p\u003e\n\u003ch4\u003e\u003cstrong\u003e3.2 Serum Insulin levels:\u003c/strong\u003e\u003c/h4\u003e\n\u003cp\u003e\u0026nbsp;The present results demonstrated a significant decrease in serum insulin levels in infected rats compared with the control group, as presented in Table (2). The highest insulin level was observed during the fourth week post-infection, with a value of\u0026nbsp;\u003cstrong\u003e2.543 \u0026plusmn; 0.5431\u003c/strong\u003e, yet it remained significantly lower than that of the control group.\u0026nbsp;\u003c/p\u003e\n\u003ch4\u003e\u003cstrong\u003e3.3 Assessment of Insulin Resistance and sensitivity:\u003c/strong\u003e\u003c/h4\u003e\n\u003cp\u003e\u0026nbsp;HOMA-IR index in all groups had different values compared with control group, HOMA-IR index is calculated using fasting plasma insulin and glucose levels. Using the previously described formula outlined in the Materials and Methods section (Section 2.6.3), a significant increase in insulin resistance was observed in the infected groups, reaching\u0026nbsp;\u003cstrong\u003e59.49 \u0026plusmn; 61.729\u003c/strong\u003e compared with the control group. Conversely, insulin sensitivity showed a marked decrease, declining to\u0026nbsp;\u003cstrong\u003e0.345 \u0026plusmn; 0.132\u003c/strong\u003e in comparison with the control group Table (2).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable (2): Effect of \u003cem\u003eGiardia\u003c/em\u003e infection on insulin-related parameters post infection\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e*A significant increase in insulin resistance was noted, approaching statistical significance (p \u0026asymp; 0.05).\u003c/p\u003e\n\u003cp\u003e*Insulin sensitivity showed a significant increase at week 2 (p = 0.01), with a lower increase at week 3 (p = 0.01) and a slight but near-significant increase at week 4 (p = 0.086).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.4 The\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eeffect of \u003cem\u003eGiardia\u003c/em\u003e infection on ALT (GPT) and AST (GOT) levels:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;According to r\u003cstrong\u003eesults,\u0026nbsp;\u003c/strong\u003eALT (GPT) and AST (GOT) levels\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003ein serum showed\u003c/strong\u003e a significant increase all\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eover the weeks post infection\u0026nbsp;compared with control group,\u0026nbsp;the results demonstrated a progressive increase with the advancement of the experimental infection period in rats, and the increase was statistically significant at the 0.05 level. The highest of ALT (GPT) value was observed after the fourth week, reaching 180.00 \u0026plusmn; 75.54. Similarly, the same trend was observed in AST (GOT) levels\u003cstrong\u003e.\u003c/strong\u003e\u0026nbsp; \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable (3): Effect of \u003cem\u003eGiardia\u003c/em\u003e infection on ALT (GPT) levels at different post-infection intervals\u003c/p\u003e\n\u003cp\u003e*Significant differences were observed between time intervals (p-values ranged from 0.043 to 0.067).\u003c/p\u003e\n\u003cp\u003eAll values were close to the statistical significance level (p = 0.05)\u003c/p\u003e\n\u003cp\u003eTable (4): Effect of \u003cem\u003eGiardia\u003c/em\u003e infection on AST (GOT) levels in male rats at different post-infection intervals\u003c/p\u003e\n\u003cp\u003e*Values at 4 weeks (p = 0.054) were close to the statistical significance level, showing a clear and gradual increase over time.\u003c/p\u003e\n\u003cp\u003eAs shown in Table (5), serum albumin levels in male rats with \u003cem\u003eGiardia\u003c/em\u003e-infected, were consistently higher than those in the control group at all post-infection intervals. Albumin concentrations increased to 4.48 \u0026plusmn; 0.303 g/dL at two weeks post-infection, followed by 4.30 \u0026plusmn; 0.182 g/dL at three weeks and 4.40 \u0026plusmn; 0.212 g/dL at four weeks, compared with a constant control value of 2.17 g/dL. Although these increases did not reach statistical significance.\u003c/p\u003e\n\u003cp\u003eTable (5): Effect of \u003cem\u003eGiardia\u003c/em\u003e infection on serum albumin levels in male rats at different post-infection intervals\u003c/p\u003e\n\u003cp\u003e*Differences were close to statistical significance (p-values ranged from 0.065 to 0.08).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe present study demonstrated that experimental \u003cem\u003eGiardia\u003c/em\u003e infection significantly alters glucose metabolism in male rats. Serum glucose levels showed a progressive and time-dependent increase following infection, reaching a peak of 472.40 ± 200.86 mg/dL at four weeks post-infection (Table 1). These findings are consistent with previous reports indicating that \u003cem\u003eGiardia\u003c/em\u003e infection can induce hyperglycemia by disrupting normal intestinal function and nutrient absorptio[18,9].The elevated glucose levels observed may result from impaired glucose uptake in enterocytes, as \u003cem\u003eGiardia\u003c/em\u003e trophozoites adhere to the intestinal epithelium and interfere with SGLT1-mediated glucose transport [8].\u003c/p\u003e\n\u003cp\u003eFurthermore, the observed decrease in serum insulin levels (Table 2) suggests that infection may impair pancreatic β-cell function or enhance insulin clearance, contributing to relative insulin deficiency. The highest insulin levels recorded at four weeks post-infection (2.543 ± 0.5431) remained significantly lower than those of the control group, indicating a disruption in insulin homeostasis. These findings align with prior studies demonstrating that \u003cem\u003eGiardia\u003c/em\u003e infection can modulate host insulin secretion, potentially through inflammatory cytokine-mediated β-cell dysfunction [1,6]. Assessment of insulin resistance using the HOMA-IR index revealed a marked increase in infected rats, reaching 59.49 ± 61.729, while insulin sensitivity decreased to 0.345 ± 0.132 compared with controls (Table 2). These changes indicate that \u003cem\u003eGiardia\u003c/em\u003e infection promotes insulin resistance, likely via systemic and local inflammatory responses as well as alterations in gut microbiota composition [9]. Chronic \u003cem\u003eGiardia\u003c/em\u003e infection has been shown to induce a pro-inflammatory environment in the intestine, which can impair insulin signaling pathways in peripheral tissues, thereby increasing insulin resistance [19]. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe progressive nature of these metabolic disturbances suggests a cumulative effect of prolonged infection. Early disruptions in glucose absorption, coupled with inflammatory-mediated insulin dysregulation, may collectively contribute to the observed hyperglycemia and reduced insulin sensitivity. Such findings highlight the systemic metabolic consequences of intestinal parasitic infections beyond local gastrointestinal pathology [20].Overall, these results reinforce the concept that \u003cem\u003eGiardia\u003c/em\u003e infection is not limited to gastrointestinal manifestations but can also affect host metabolic regulation, including glucose homeostasis, insulin secretion, and insulin sensitivity. These observations have implications for understanding parasite-induced metabolic dysregulation, particularly in populations with high prevalence of giardiasis.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp; According to r\u003cstrong\u003eesults,\u0026nbsp;\u003c/strong\u003ethe present study demonstrated\u0026nbsp;\u003cstrong\u003ethat the effect of\u0026nbsp;\u003c/strong\u003e\u003cem\u003eGiardia\u003c/em\u003e\u003cstrong\u003e\u0026nbsp;infection on ALT, AST, and Albumin levels\u003c/strong\u003e in the experimental\u0026nbsp;\u003cem\u003eGiardia\u003c/em\u003e infection in male rats induced significant alterations in liver function biomarkers. Serum ALT (GPT) and AST (GOT) levels showed a progressive and time-dependent increase throughout the post-infection period, with the highest ALT value recorded at four weeks post-infection \u003cstrong\u003e(\u003c/strong\u003e\u003cstrong\u003e180.00 ± 75.54 U/L\u003c/strong\u003e\u003cstrong\u003e)\u003c/strong\u003e and a similar trend observed for AST \u003cstrong\u003e(\u003c/strong\u003e\u003cstrong\u003e492.45 ± 389.57 U/L\u003c/strong\u003e\u003cstrong\u003e)\u003c/strong\u003e (Tables 3 and 4). These elevations were statistically significant or approached the threshold for significance (p = 0.05), indicating hepatocellular stress or damage following\u0026nbsp;\u003cem\u003eGiardia\u003c/em\u003e infection.\u003c/p\u003e\n\u003cp\u003eThe observed increase in transaminase levels may reflect direct or indirect hepatic effects induced by the parasite. Although\u0026nbsp;\u003cem\u003eGiardia\u003c/em\u003e primarily colonizes the small intestine, systemic effects mediated by inflammatory responses, oxidative stress, and gut-liver axis interactions can result in liver enzyme elevation. Similar findings were reported by [6, 9], who observed that intestinal parasitic infections could induce oxidative and inflammatory-mediated hepatocellular injury. The gradual increase over time suggests that prolonged infection exacerbates hepatic stress, possibly due to chronic intestinal inflammation, malabsorption of nutrients, and systemic immune activation.\u003c/p\u003e\n\u003cp\u003eFurthermore, the present study revealed an increase in serum albumin concentrations in infected rats compared with controls (Table 5). Albumin levels were consistently higher across all post-infection intervals, reaching\u0026nbsp;\u003cstrong\u003e4.48 ± 0.303 g/dL\u003c/strong\u003e at two weeks post-infection. Although these differences did not reach statistical significance (p-values 0.065–0.08), the trend suggests that\u0026nbsp;\u003cem\u003eGiardia\u003c/em\u003e infection may alter protein metabolism or induce compensatory hepatic protein synthesis. Previous studies have shown that parasitic infections can disrupt the balance between protein synthesis and degradation, affecting plasma protein levels, including albumin [18, 19]\u0026nbsp;\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003e\u0026nbsp;These findings highlight that\u0026nbsp;\u003cem\u003eGiardia\u003c/em\u003e infection can exert systemic metabolic effects beyond the intestinal tract. The observed elevations in liver enzymes indicate hepatocellular stress, likely mediated by inflammation and oxidative mechanisms, while the trend toward increased albumin levels may reflect adaptive hepatic responses to maintain plasma protein homeostasis. Such alterations underscore the broader metabolic consequences of intestinal parasitic infections, particularly in chronic or high-intensity infections.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003e6. Acknowledgments:\u0026nbsp;\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;We extend our sincere thanks and appreciation to the staff of the Department of Life Sciences, College of Education for Women, University of Mosul.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e7. Conflict of Interest:\u0026nbsp;\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;The authors declare no conflict of interest regarding this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e8.Funding :\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;This study did not receive any specific financial support from any public or private entity.\u003c/p\u003e\n\u003cp\u003e9.\u0026nbsp;\u003cstrong\u003eDeclarations Statement\u003c/strong\u003e:\u003cbr\u003e\u0026nbsp; \u0026nbsp;The datasets generated and analysed during this study are included in this published article. Data Availability\u003cbr\u003e\u0026nbsp;The datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e10\u003cstrong\u003e. Data Availability:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAdditional data are available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003e11. \u003cstrong\u003eConsent for Publication\u003c/strong\u003e:\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Not Applicable in this section, due to the use of anonymized samples.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eDemichele E, Sosnowski O, Flood D, Allain T, Buret AG. \u003cstrong\u003e\u003cem\u003eGiardia duodenalis\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e stabilizes HIF-1\u0026alpha; and induces glycolytic alterations in intestinal epithelial cells.\u003c/strong\u003e Sci Rep. 2025; 15:28852.\u003c/li\u003e\n\u003cli\u003eMajeed HA. \u003cstrong\u003eStudy the relationship between giardiasis incidence and selected epidemiological factors in Baghdad City.\u003c/strong\u003e Al-Mustansiriyah J Sci. 2019; 29(3):35\u0026ndash;44.\u003c/li\u003e\n\u003cli\u003eIsmail I, Hakeem K, Ali A. \u003cstrong\u003eAntioxidation potential of date palm fruits and their role in oxidative stress\u0026ndash;related diseases.\u003c/strong\u003e J Food Sci Technol. 2022; 59(7):1802\u0026ndash;1811.\u003c/li\u003e\n\u003cli\u003eAl-Daoody AAK, Ismail SM, Ezadin ZY, Kakl D. \u003cstrong\u003ePrevalence of \u003c/strong\u003e\u003cem\u003eGiardia lamblia\u003c/em\u003e\u003cstrong\u003e among residents of Hawler, Soran, and Chamchamal cities, northern Iraq.\u003c/strong\u003e Pak-Euro J Med Life Sci. 2020; 3(2):28\u0026ndash;36.\u003c/li\u003e\n\u003cli\u003eSolaymani-Mohammadi S, Eckmann L, Singer SM. \u003cstrong\u003eInterleukin-21 in inflammation and immunity during parasitic diseases.\u003c/strong\u003e Front Immunol. 2019; 9:401. doi:10.3389/fimmu.2018.00401.\u003c/li\u003e\n\u003cli\u003eSolaymani-Mohammadi S. \u003cstrong\u003eMucosal defense against \u003c/strong\u003e\u003cem\u003eGiardia\u003c/em\u003e\u003cstrong\u003e at the intestinal epithelial cell interface.\u003c/strong\u003e Front Immunol. 2022; 13:817468.\u003c/li\u003e\n\u003cli\u003eMayo Clinic. \u003cstrong\u003eGiardia infection: Symptoms and causes.\u003c/strong\u003e Rochester (MN): Mayo Foundation for Medical Education and Research; 2023 [cited 2025 Jan 10]. Available from: https://www.mayoclinic.org\u003c/li\u003e\n\u003cli\u003eYu LCH, Huang CY, Kuo WT, Sayer H, Turner JR, Buret AG. \u003cstrong\u003eSGLT-1\u0026ndash;mediated glucose uptake protects human intestinal epithelial cells against \u003c/strong\u003e\u003cem\u003eGiardia duodenalis\u003c/em\u003e\u003cstrong\u003e-induced apoptosis.\u003c/strong\u003e Int J Parasitol. 2008; 38(8\u0026ndash;9):923\u0026ndash;934.\u003c/li\u003e\n\u003cli\u003eKlimczak S, Packi K, Rudek A, Wenclewska S, Kurowski M, Kurczabinska D, et al. \u003cstrong\u003eThe influence of \u003c/strong\u003e\u003cem\u003eGiardia lamblia\u003c/em\u003e\u003cstrong\u003e on host glucose and lipid metabolism.\u003c/strong\u003e Metabolites. 2024; 25(16):8627. Doi: 10.3390/metabo25168627.\u003c/li\u003e\n\u003cli\u003eAmorim RM, Oliveira DR, Freitas SE, Viana MP, Borges EL. \u003cstrong\u003eEffect of giardiasis combined with low-protein diet on intestinal absorption of glucose and electrolytes in gerbils.\u003c/strong\u003e Exp Parasitol. 2012; 131(4):448\u0026ndash;451.\u003c/li\u003e\n\u003cli\u003eSlevaney A, Carter J, Morrison L. \u003cstrong\u003eOxidative stress and immune responses during intestinal protozoan infections.\u003c/strong\u003e Parasite Immunol. 2024; 46(3):e12987.\u003c/li\u003e\n\u003cli\u003eRitchie LS, Lin S, Moon AP, Frick LP, Williams JE, Asakura S, Hishinuma Y. \u003cstrong\u003eThe possible effects of pH and specific gravity on the ether-sedimentation procedure in concentrating eggs and cysts.\u003c/strong\u003e Am J Trop Med Hyg. 1960; 9(5):444\u0026ndash;449.\u003c/li\u003e\n\u003cli\u003eCraft JC. \u003cstrong\u003eExperimental infection with \u003c/strong\u003e\u003cem\u003eGiardia lamblia\u003c/em\u003e\u003cstrong\u003e in rats.\u003c/strong\u003e J Infect Dis. 1982; 145(4):495\u0026ndash;498. doi:10.1093/infdis/145.4.495.\u003c/li\u003e\n\u003cli\u003eParasuraman S, Balamurugan S, Christapher PV, Petchi RR, Yeng WY, Sujithra J, Vijaya C. \u003cstrong\u003eEvaluation of antidiabetic and antihyperlipidemic effects of \u003c/strong\u003e\u003cem\u003eOcimum tenuiflorum\u003c/em\u003e\u003cstrong\u003e.\u003c/strong\u003e Pharmacogn Res. 2015; 7(2):156\u0026ndash;162. doi:10.4103/0974-8490.157997.\u003c/li\u003e\n\u003cli\u003eGreenfield EA. \u003cstrong\u003eSampling and preparation of mouse and rat serum.\u003c/strong\u003e Cold Spring Harb Protoc. 2017; 2017(11):pdb.prot100271. doi:10.1101/pdb.prot100271.\u003c/li\u003e\n\u003cli\u003eGutch M, Kumar S, Razi SM, Gupta KK, Gupta A. \u003cstrong\u003eAssessment of insulin sensitivity/resistance.\u003c/strong\u003e Indian J Endocrinol Metab. 2015; 19(1):160\u0026ndash;164. doi:10.4103/2230-8210.146874.\u003c/li\u003e\n\u003cli\u003eMinh HV, Tien HA, Sinh CT, Thang DC, Chen CH, Tay JC, et al. \u003cstrong\u003eAssessment of preferred methods to measure insulin resistance in Asian patients with hypertension.\u003c/strong\u003e J Clin Hypertens (Greenwich). 2021; 23(3):529\u0026ndash;537. doi:10.1111/jch.14155.\u003c/li\u003e\n\u003cli\u003eGil FF, Moreira de Mendes G, Aquino Teixeira MC, Oliveira DR, Cruz RE, Santos JFG, et al. \u003cstrong\u003eGiardia lamblia infection induces changes in the biochemical profile of gerbils (\u003c/strong\u003e\u003cem\u003eMeriones unguiculatus\u003c/em\u003e\u003cstrong\u003e).\u003c/strong\u003e J Infect Dev Ctries. 2025; 19(6):962\u0026ndash;970.\u003c/li\u003e\n\u003cli\u003eBarash NR, Maloney JG, Singer SM, Dawson SC. \u003cstrong\u003eGiardia alters commensal microbial diversity throughout the murine gut.\u003c/strong\u003e Infect Immun. 2017; 85(6):e00023-17.\u003c/li\u003e\n\u003cli\u003eW\u003cstrong\u003eu J, He C, Bu J, Luo Y, Yang S, Ye C, Yu S, He B, Yin Y, and Yang X.\u003c/strong\u003e Betaine attenuates LPS-induced downregulation of occludin and claudin-1 and restores intestinal barrier function. \u003cstrong\u003eBMC Vet Res.\u003c/strong\u003e 2020; 16(1):75. Doi: 10.1186/s12917-020-02298-3.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTables 1 to 5 are available in the supplementary files section\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Department of Biology, College of Education for Girls, University of Mosul, Mosul, Iraq","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Giardia Lamblia, Intestinal parasite, insulin resistance, liver enzymes, glucose concentrations","lastPublishedDoi":"10.21203/rs.3.rs-9226597/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9226597/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe present study investigated the metabolic and hepatic effects of experimental \u003cem\u003eGiardia\u003c/em\u003e infection in male rats over a four-week post-infection period. Results demonstrated that \u003cem\u003eGiardia\u003c/em\u003e infection significantly disrupted glucose homeostasis, as evidenced by a progressive and time-dependent elevation in serum glucose levels. Infected rats exhibited markedly higher glucose concentrations compared with controls, reaching a peak of 472.40\u0026thinsp;\u0026plusmn;\u0026thinsp;200.86 mg/dL at four weeks post-infection, indicating impaired intestinal absorption and dysregulated glucose metabolism. Concurrently, serum insulin levels were significantly reduced in infected rats, with the highest post-infection value (2.543\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5431) remaining lower than the control group. Assessment of insulin resistance using the HOMA-IR index revealed a notable increase in infected groups (59.49\u0026thinsp;\u0026plusmn;\u0026thinsp;61.73), accompanied by a significant decline in insulin sensitivity (0.345\u0026thinsp;\u0026plusmn;\u0026thinsp;0.132). These findings suggest that \u003cem\u003eGiardia\u003c/em\u003e infection promotes insulin resistance and disrupts systemic glucose regulation, likely through inflammatory mechanisms and alterations in gut epithelial function.\u003c/p\u003e \u003cp\u003elevels increased progressively over the four-week period, reaching 180.00\u0026thinsp;\u0026plusmn;\u0026thinsp;75.54 U/L and 492.45\u0026thinsp;\u0026plusmn;\u0026thinsp;389.57 U/L, respectively, reflecting hepatocellular stress or damage induced by systemic inflammatory responses associated with intestinal infection. In contrast, serum albumin concentrations were consistently higher in infected rats compared with controls (up to 4.48\u0026thinsp;\u0026plusmn;\u0026thinsp;0.303 g/dL), though these changes did not reach statistical significance, potentially indicating adaptive hepatic protein synthesis in response to infection.\u003c/p\u003e \u003cp\u003eOverall, these results demonstrate that \u003cem\u003eGiardia\u003c/em\u003e infection exerts profound systemic metabolic and hepatic effects, including hyperglycemia, hypoinsulinemia, increased insulin resistance, and elevated liver enzymes. The findings highlight the broader physiological impact of intestinal parasitic infections and underscore the need to consider their metabolic consequences in both experimental models and clinical settings.\u003c/p\u003e","manuscriptTitle":"Induction of Giardia spp. infection and biochemical profiles in rats","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-27 04:26:07","doi":"10.21203/rs.3.rs-9226597/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"8c65b073-912b-4e7e-bce6-6115748f38c7","owner":[],"postedDate":"March 27th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":65146383,"name":"Parasitology"}],"tags":[],"updatedAt":"2026-03-27T04:26:07+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-27 04:26:07","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9226597","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9226597","identity":"rs-9226597","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}