Polystyrene Nanoplastics Induce Multi-Organ Toxicity in the Rainbow Trout (Oncorhynchus mykiss): An Integrated Assessment of Physiological, Immunological, and Molecular Responses

Polystyrene Nanoplastics Induce Multi-Organ Toxicity in the Rainbow Trout (Oncorhynchus mykiss): An Integrated Assessment of Physiological, Immunological, and Molecular Responses | 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 Polystyrene Nanoplastics Induce Multi-Organ Toxicity in the Rainbow Trout (Oncorhynchus mykiss): An Integrated Assessment of Physiological, Immunological, and Molecular Responses Melika Mirzaei Nashtoroudi, Mahboobeh Afrand, Kamran Rezaei Tavabe, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7212510/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 Plastics constitute a major category of waste in aquatic ecosystems, significantly exacerbating environmental pollution and endangering marine organisms. Examining plastic pollution in these ecosystems is essential for understanding its effects and formulating appropriate strategies for their protection. This study investigated the toxicity resulting from 28-days of exposure to different concentrations of polystyrene nanoplastics (PS-NPs; average size 73 nm; T1–0.1, T2–10, and T3–100 mg/kg of diet). After a 28-day exposure to PS-NPs, the growth performance, hematological and immunological indices, antioxidant parameters, plasma cortisol levels, tissue histopathology, and gene expression in Oncorhynchus mykiss liver and spleen were examined. Examining plastic pollution in aquatic ecosystems is essential for understanding its impact and formulating appropriate strategies to safeguard their health. Our findings indicate that PS-NPs significantly affected the physiology and histopathology of O. mykiss , with the severity of effects being dose-dependent. The survival rate of the fish decreased significantly, and most immuno-hematological parameters, as well as electrolyte levels (sodium and potassium), showed a marked decline compared to the control group; however, lymphocyte counts increased. The activity of the antioxidant enzyme SOD exhibited a decreasing trend, whereas ROS activity and the relative expression levels of HSP-70 and TNF-α (in both tissues), as well as SOD (in the liver), increased, and IL-10 (in both tissues) decreased with higher concentrations of PS-NPs. Moreover, blood glucose and cortisol levels exhibited significant dose-dependent reductions. Histopathological analysis indicated moderate to severe changes in the liver, spleen, and intestinal tissue of the group subjected to a dietary exposure of 100 mg/kg of PS-NPs. The findings demonstrate that PS-NPs negatively impacted the physiology, immune response, and gene expression in the rainbow trout. This indicates that particulate plastic pollution adversely affects aquatic organisms and may also threaten human health via the food chain and the chemical toxicity of these particles. Fish Nanoplastic toxicity Environmental stress Biochemical biomarkers Immune system disruption Full Text Additional Declarations No competing interests reported. Supplementary Material is not available with this version. Supplementary Files GraphicalAbstract.jpg Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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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-7212510","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":506661747,"identity":"1b61161b-58dc-4937-878f-91e6d6a55554","order_by":0,"name":"Melika Mirzaei Nashtoroudi","email":"","orcid":"","institution":"University of Tehran","correspondingAuthor":false,"prefix":"","firstName":"Melika","middleName":"Mirzaei","lastName":"Nashtoroudi","suffix":""},{"id":506661748,"identity":"79d4d1a8-35a3-4845-9888-2880827c9a5b","order_by":1,"name":"Mahboobeh Afrand","email":"","orcid":"","institution":"University of 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Examining plastic pollution in these ecosystems is essential for understanding its effects and formulating appropriate strategies for their protection. This study investigated the toxicity resulting from 28-days of exposure to different concentrations of polystyrene nanoplastics (PS-NPs; average size 73 nm; T1\u0026ndash;0.1, T2\u0026ndash;10, and T3\u0026ndash;100 mg/kg of diet). After a 28-day exposure to PS-NPs, the growth performance, hematological and immunological indices, antioxidant parameters, plasma cortisol levels, tissue histopathology, and gene expression in \u003cem\u003eOncorhynchus mykiss\u003c/em\u003e liver and spleen were examined. Examining plastic pollution in aquatic ecosystems is essential for understanding its impact and formulating appropriate strategies to safeguard their health. Our findings indicate that PS-NPs significantly affected the physiology and histopathology of \u003cem\u003eO. mykiss\u003c/em\u003e, with the severity of effects being dose-dependent. The survival rate of the fish decreased significantly, and most immuno-hematological parameters, as well as electrolyte levels (sodium and potassium), showed a marked decline compared to the control group; however, lymphocyte counts increased. The activity of the antioxidant enzyme SOD exhibited a decreasing trend, whereas ROS activity and the relative expression levels of HSP-70 and TNF-α (in both tissues), as well as SOD (in the liver), increased, and IL-10 (in both tissues) decreased with higher concentrations of PS-NPs. Moreover, blood glucose and cortisol levels exhibited significant dose-dependent reductions. Histopathological analysis indicated moderate to severe changes in the liver, spleen, and intestinal tissue of the group subjected to a dietary exposure of 100 mg/kg of PS-NPs. The findings demonstrate that PS-NPs negatively impacted the physiology, immune response, and gene expression in the rainbow trout. 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