Investigating the effect of human amniotic membrane gel to minimize adhesions in endometriosis: findings from an experimental study using a rat model

Postoperative adhesions and inflammation remain major challenges following endometriosis surgery. Human amniotic mem- brane gel (HAG) has emerged as a potential therapeutic strategy with both anti-adhesive and anti-inflammatory properties. This study aimed to evaluate the efficacy of intraperitoneal HAG in reducing adhesion severity, lesion persistence, and inflammatory cytokine levels in an ex- perimental rat model of endometriosis.

Forty-four adult female Wistar rats underwent surgical induction of endometriosis through autotransplantation of uterine horn tissue. After 3 weeks, the animals were randomized into two groups (n=22 each): one receiving intraperitoneal HAG and the other receiving normal saline during a second laparotomy. Adhesion severity was evaluated using the Hoffmann and Lauder scoring systems. Two weeks af- ter the intervention, endometriotic lesion size was measured. Serum levels of interleukin (IL)-6 and IL-1β were assessed at three time points. Histopathological examination was conducted to evaluate the presence of endometriotic tissue, fibrosis, abscess formation, and adipose tis- sue remodeling.

Rats treated with HAG showed a significant reduction in lesion size (6.8 mm² vs. 81 mm², p<0.001) and significantly lower adhesion scores (p<0.001). Persistent endometriosis was observed in only 36% of animals in the HAG group compared with 95.5% in the control group (p<0.001). Histological analysis demonstrated fewer fibrotic and purulent reactions and a shift toward adipose tissue remodeling in the HAG-treated animals. Serum IL-6 and IL-1β levels decreased significantly in the HAG group, whereas both cytokines increased in the control group (p<0.001 for both).

HAG significantly improved macroscopic, histological, and biochemical outcomes in this experimental model. These findings suggest that HAG may serve as a biologically active adjunct for reducing postoperative adhesion formation and inflammation in endometrio- sis.

Amniotic membrane; Animal models; Endometriosis; Inflammation mediators; Postoperative complications; Tissue adhesions

Postoperative pelvic adhesions are a frequent complication of en- dometriosis surgery and contribute to chronic pain, infertility, and bowel obstruction. Surgical trauma initiates a wound-healing cas- cade that can result in the formation of fibrous bands between peri- toneal surfaces [1]. The use of biochemical barriers such as hyaluron- ic acid (HA) has previously been proposed as an effective strategy for reducing postoperative adhesions. HA forms a temporary physical

1. Materials and animals This experimental study was conducted in adult, nonpregnant fe- male Wistar albino rats weighing 220 to 250 g. The animals were housed in standard cages at the Center for Experimental Studies, Shahid Beheshti University of Medical Sciences, under controlled en- vironmental conditions (temperature, 22±2 °C; 12-hour light/12- hour dark cycle) with free access to food and water. Amniotic mem- brane allograft gel was obtained from Lifescell (International Bioim- plant of Borna Co.). Commercial enzyme-linked immunosorbent as- say (ELISA) kits were obtained from Karmania Pars Gene Company. All procedures were approved by the Research and Ethics Com- mittee of Iran University of Medical Sciences, Tehran, Iran (IR.IUMS. REC.1399.726), and were conducted in accordance with the Guide for the Care and Use of Laboratory Animals (National Institutes of Health Publication No. 80-23, revised 1996). After an adaptation peri- od and before the first laparotomy, each rat received a subcutaneous injection of 2.0 mg/kg estradiol to support the establishment of en- dometriotic implants. 2. Induction of endometriosis At the time of the first laparotomy, the rats were in the estrus phase, during which estrogen levels are naturally elevated and facili- tate implantation and survival of endometrial fragments. This timing is consistent with established protocols for endometriosis induction in rodent models. In line with previous studies demonstrating that exogenous estradiol enhances endometriosis development [16], in- tramuscular estradiol was also administered to further improve le- sion establishment. Importantly, the ovaries were preserved to main- tain endogenous hormonal cycles, thereby better simulating the hormonal milieu of endometriosis. Thus, the combination of natural estrus, exogenous estradiol, and ovarian preservation optimized the conditions for reliable induction of peritoneal endometriosis [16,17]. Anesthesia was induced with intramuscular ketamine hydrochloride (60 mg/kg) and xylazine hydrochloride (10 mg/kg) administered in the same syringe. Before surgery, tail vein blood samples were col- lected to measure baseline serum IL-6 and IL-1β levels. A vertical midline abdominal incision of approximately 3 cm was made, and the two uterine horns were exposed. The right uterine horn was ligated with a 4-0 silk suture, and a 1-cm segment was ex- cised and opened longitudinally. Sterile phosphate-buffered saline was used to keep the tissue moist. The uterine segment was then divided into three equal parts. All three fragments were transplanted onto the inner surface of the right abdominal wall, with the endometrial surface facing the perito- neum. The serosal surface was positioned against the peritoneal sur- layer between healing peritoneal surfaces, thereby preventing direct tissue apposition and adhesion formation. HA gel has been shown to significantly decrease the incidence and severity of pelvic adhesions following gynecologic surgery, particularly surgery for endometriosis [2,3]. More recently, natural bioactive gels such as human amniotic membrane gel (HAG) have attracted attention because of their dual function: they not only serve as physical barriers but also deliver an- ti-inflammatory and regenerative signals to the surgical site. These amniotic-derived products are rich in growth factors, extracellular matrix proteins, HA, and immunomodulatory cytokines that support tissue repair and modulate inflammation [4,5]. In preclinical studies, they have been shown to reduce fibrosis, downregulate inflammato- ry pathways such as transforming growth factor-β (TGF-β), and sup- press proinflammatory cytokines including interleukin 6 (IL-6) and IL- 1β [6-8]. Endometriosis is characterized by a proinflammatory peritoneal environment, with IL-6 and IL-1β identified as key mediators of dis- ease progression and adhesion formation. Women with endometrio- sis have significantly elevated levels of IL-6 and IL-1β in serum and peritoneal fluid compared with disease-free controls [9]. IL-6, in par- ticular, correlates with endometriosis severity and has been implicat- ed in lesion proliferation and survival, especially through its soluble receptor, which enhances IL-6 signaling [10]. Surgical injury further amplifies these cytokines. Experimental models have shown that early postoperative surges in IL-6 and IL-1β are strongly associated with the extent of subsequent adhesions [11,12]. IL-1β promotes ad- hesion formation by reducing fibrinolysis; it induces plasminogen activator inhibitor-1, leading to persistence of fibrin scaffolds, and it stimulates mesothelial cells to undergo profibrotic changes [13]. IL-6, often induced downstream of IL-1β and tumor necrosis factor-α, fur- ther drives fibrogenesis by triggering mesothelial-to-myofibroblast transition and altering the expression of matrix-remodeling en - zymes, thereby reinforcing adhesion development [13]. Given the central role of IL-6 and IL-1β, anti-inflammatory interventions target- ing these cytokines may markedly influence postoperative out - comes. Indeed, blocking IL-1β activity in animal models reduces peritoneal adhesion formation [14]. Likewise, neutralization of IL-6 signaling with an anti-IL-6 receptor antibody has been shown to ab- rogate neutrophil recruitment and significantly diminish adhesion bands in a murine surgery model [ 15]. These findings underscore that dampening the IL-6/IL-1β-driven inflammatory cascade after surgery may reduce adhesion formation and fibrosis and potentially lower endometriosis recurrence. Collectively, these insights provide a strong rationale for therapies that combine physical anti-adhesion barriers such as HA gel with strategies that modulate IL-6 and IL-1β, with the aim of improving healing and long-term outcomes in pa- tients with endometriosis. https://doi.org/10.5653/cerm.2025.091102 Clin Exp Reprod Med [Epub ahead of print] face and fixed with 4–0 nonabsorbable silk sutures (Figure 1). During the procedure, the surgical field was frequently moistened with nor- mal saline to prevent tissue drying. Before closure of the abdominal wall, 2 mL of saline was instilled into the peritoneal cavity. The abdominal wall was closed in layers using simple interrupted 2–0 polyglactin 910 sutures. After surgery, the animals were housed individually and monitored for 3 weeks. They received 50 µg/kg in- tramuscular depot estradiol twice weekly during this period. Body weight and general health were monitored regularly, and no mortal- ity occurred during the study. 3. HAG application At the end of the third week, all animals underwent a second lapa- rotomy to verify the viability of the endometriotic implants by histo- pathological assessment (Figure 2). In all animals, the implants were measured in two dimensions (length and width, in mm) using a cali- Figure 1. Surgical procedure and assessment of animal model of endometriosis. (A) Induction of endometriosis (the white arrow shows the left uterine horn). (B) Endometriotic implant before intervention. (C) Adhesion severity and size of endometriotic implant in the human amniotic membrane gel group. (D) Adhesion severity and size of endometriotic implant in the control group. Figure 2. Pathological views of ectopic endometriosis. (A) After induction of endometriosis, (B) after human amniotic membrane gel application, and (C) control group. Hematoxylin and eosin staining; original magnification: A, ×100; B and C, ×40. www.eCERM.org 3 R Derakhshan et al. HAG and endometriosis adhesions AA CC BB DD AA BB CC per, photographed with a digital camera, and documented in the study records [18]. Immediately thereafter, 44 rats with established endometriotic implants were randomly assigned to two groups: group A (HAG group, n=22) and group B (normal saline group, n=22). Randomization was performed immediately before the inter- vention, ensuring that only animals with successful model induction were included. In group A, sterile HAG (International Bioimplant of Borna Co., Teh- ran, Iran) was instilled into the abdominal cavity during laparotomy, and the abdominal wall was closed with simple 2–0 polyglactin 910 sutures. In group B, normal saline was instilled into the abdominal cavity during laparotomy according to protocols similar to those used in previous experimental studies [17,19]. 4. Implant measurements and histopathology Two weeks after HAG or saline application (i.e., 5 weeks after in- duction of endometriosis), blood samples were again obtained from the tail vein under light sedation to assess serum interleukin levels. The rats were then humanely euthanized using nitrous oxide. During the final laparotomy, adhesions were evaluated in each group using Hoffmann’s quantitative score and Lauder’s qualitative grading sys- tem. A researcher blinded to group allocation measured the width and length of each implant with a caliper. Endometrial implants were excised and fixed in formaldehyde for routine histopathological examination. Both the biochemist and the histopathologist were blinded to treatment allocation. Data on lesion size, adhesion severity, and gross appearance were recorded using a structured checklist, and standardized photographs were taken at each laparotomy to docu- ment adhesion formation and implant morphology. The histological diagnosis of endometriosis was based on the presence of endome- trial glands and stroma, with epithelial lining and luminal formation within the ectopic implants [17]. In addition, the presence of fibrosis, abscess formation, and adipose tissue reaction was recorded as part of the pathological evaluation. 5. Cytokine assays Serum levels of IL-6 and IL-1β were measured using enzyme-linked immunosorbent assay (ELISA) kits according to the manufacturers’ instructions. IL-6 and IL-1β concentrations were determined using commercially available ELISA kits. 6. Statistical analysis All analyses were performed using SPSS ver. 24 (IBM Co.). Continu- ous variables were assessed for normality using the Kolmogorov– Smirnov test. Repeated-measures analysis of variance was used to evaluate temporal trends across the three measurement points and their interaction with treatment group. Greenhouse–Geisser correc- tions were applied when the assumption of sphericity was violated. For comparisons between the two groups at individual time points (baseline, week 3, and post-treatment), the Mann–Whitney U test was used because cytokine levels and lesion measurements did not fully meet parametric assumptions. The Wilcoxon signed-rank test was used to assess within-group changes over time (pre- vs. post-treatment). Adhesion severity scores (Hoffmann and Lauder) were also compared between groups using the Mann–Whitney U test. All categorical histopathological findings were analyzed using the chi-square test or Fisher’s exact test, as appropriate. Results were reported as mean±standard deviation for continuous variables and frequency (percentage) for categorical variables. A two-sided p<0.05 was considered statistically significant.

1. Surgical outcomes and adhesion severity All 44 animals completed the study and were included in the anal- ysis. At baseline, the two groups were comparable in lesion size and cytokine profiles, confirming that randomization produced well-bal- anced groups. Endometriotic implants initially appeared as typical vascularized or cystic nodules surrounded by filmy or inflammatory adhesions. By the end of the experiment, the difference between groups had become both visually and statistically evident. Lesions in the HAG-treated animals had shrunk dramatically, with post-interven- tion lesion size decreasing to approximately 7 mm², in contrast to the control group, in which lesions remained large, averaging approxi- mately 81 mm² (p<0.001). The overall reduction in lesion size from baseline was also markedly greater in the HAG group (approximately 80 mm²) than in the control group (approximately 9 mm²). As shown in Table 1, this improvement remained significant within animals over time, whereas the control group showed no meaningful regres- sion. Adhesion scores showed a similar pattern. Both Hoffmann and Lauder scores were substantially lower in rats receiving HAG, with mean Hoffmann scores of approximately 2.5 versus 6.4 in the control group and mean Lauder scores of 1.0 versus 2.9, respectively (both p<0.001). Figure 1 illustrates these macroscopic differences. Overall, the surgical findings indicate a consistent and robust therapeutic ef- fect of HAG on both lesion size and adhesion severity. 2. Histopathological findings Histological evaluation reinforced the macroscopic findings. Only a minority of HAG-treated rats showed evidence of persistent endo- metriosis (36%), whereas nearly all animals in the control group re- https://doi.org/10.5653/cerm.2025.091104 Clin Exp Reprod Med [Epub ahead of print] mained positive for active lesions (95.5%; p<0.001). The pattern of tissue changes also differed meaningfully between groups. Fibrosis and abscess formation—markers of chronic or ongoing inflammato- ry activity—were frequent in control animals, whereas these features were much less common in animals exposed to HAG. In contrast, ad- ipose tissue reaction, which is more consistent with tissue repair and remodeling, predominated in the HAG group. These distributions are summarized in Table 2. Figure 2A shows the histological appearance of endometriotic im- plants immediately after confirmation of endometriosis during the second laparotomy. Figure 2B, 2C show histological sections of im- plants 2 weeks after HAG treatment (Figure 2B) and normal saline treatment in the control group (Figure 2C), highlighting the differ- ences in tissue response between treated and untreated animals. In Figure 2B, following HAG treatment, the endometriotic epithelium is absent, and only residual fibrotic tissue remains. 3. Serum cytokine levels Changes in systemic cytokine levels closely mirrored the surgical and histological outcomes. At baseline, IL-6 and IL-1β levels were similar between groups, indicating no pre-existing differences. Fol- lowing treatment, the trajectories diverged sharply. IL-6 levels de- creased steadily in HAG-treated animals, falling to approximately 1.24 pg/mL, whereas levels increased in the control group, reaching approximately 2.65 pg/mL at the same time point (p<0.001). A high- ly significant time-by-group interaction confirmed that the pattern of IL-6 change differed fundamentally between the two groups. IL-1β showed a similar pattern. In the HAG group, IL-1β decreased to approximately 1.38 pg/mL, whereas in control animals it increased sharply to more than 3.2 pg/mL (p<0.001). The linear trend over time was strong and highly significant for both cytokines, reflecting a sus- tained anti-inflammatory response to HAG. These patterns corre- spond closely to the macroscopic regression of lesions and the histo- logical shift toward healing. The cytokine trajectories are illustrated in Figure 3, and the full numerical data are summarized in Table 3.

This study demonstrates that intraperitoneal HAG significantly at- tenuated endometriosis progression and postoperative adhesions in a rat model. Animals treated with HAG had markedly smaller endo- metriotic lesions and substantially lower adhesion severity, based on Hoffmann and Lauder scores, than saline-treated controls. These findings are consistent with prior evidence that barrier gels can re- duce pelvic adhesions. A recent meta-analysis of gynecologic surgery showed that HA gel significantly decreases overall adhesion forma- tion [2]. Likewise, Moazezi et al. [20] reported that a human amni- on-derived jelly applied after laparotomy resulted in lower adhesion scores and histologically milder adhesions than those observed in untreated rats. Our study extends these observations by demonstrat- Table 1. Pre- and post-intervention surgical characteristics of lesions in two groups Group  HAG Control Mann–Whitney p-value Hoffmann adhesion score 3 (0 to 5) 6 (4 to 10) < 0.001 Lauder adhesion score 1 (0 to 2) 2 (1 to 5) < 0.001 Size difference (mm 2 ) 81 (28 to 158) 8 (–36 to 52) < 0.001 Size: Pre-intervention (mm 2 ) a) 85 (36 to 162) 85 (36 to 162) 0.777 Size: Post-intervention (mm 2 ) a) 4 (4 to 27) 75 (33 to 132) < 0.001 Within-group changes p-value < 0.001 0.083 Values are presented as median (range). Within-group changes were assessed using the Wilcoxon signed-rank test. HAG, human amniotic membrane gel. a) Within-group changes were assessed using the Wilcoxon signed-rank test. Table 2. Serum cytokine levels pre- and post-intervention in two study groups Cytokine Time point HAG Control Mann–Whitney p-value p-value for trend: comparison between groups a) IL-6 Baseline 1.57 ± 0.51 1.63 ± 0.56 0.705 Before intervention 1.77 ± 0.16 1.85 ± 0.32 0.168 < 0.001 Post-intervention 1.24 ± 0.12 2.65 ± 0.072 < 0.001 IL-1β Baseline 1.93 ± 0.33 1.92 ± 0.32 0.858 Before intervention 2.01 ± 0.29 2.05 ± 0.22 0.373 < 0.001 Post-intervention 1.38 ± 0.01 3.28 ± 0.11 < 0.001 Values are presented as mean±standard deviation. HAG, human amniotic membrane gel; IL, interleukin. a) Trend p-values reflect within-subject linear change from baseline to post-intervention (repeated-measures analysis of variance). www.eCERM.org 5 R Derakhshan et al. HAG and endometriosis adhesions ing concurrent modulation of inflammatory pathways in an endo- metriosis-specific context. A plausible explanation for the benefits of HAG is its combination of barrier function and intrinsic anti-inflammatory properties. By physically separating injured peritoneal surfaces, the gel likely helped prevent the initial fibrin bridging that leads to adhesions, similar to the action of other anti-adhesion barriers [21]. Beyond this mechanical role, the amniotic membrane is known to release bioac- tive factors that suppress inflammation and fibrosis. In a mouse sur- gery model, fragmented amniotic membrane significantly reduced postoperative adhesion incidence and fibrosis [22]. Consistent with these observations, HAG-treated rats in our study showed a lower in- cidence of fibrotic tissue and abscess formation on histological ex- amination, suggesting that HAG attenuated the intense inflammato- ry response that can drive scar formation. Instead, we observed an adipose tissue-rich reaction at lesion sites in the HAG group, which may indicate a more regenerative and less fibrotic healing process. This interpretation is consistent with reports that the amniotic mem- brane can promote constructive healing while limiting excessive scarring [22]. Furthermore, the amniotic membrane contains anti- proteases and antimicrobial peptides [23,24], which may explain the absence of abscesses in HAG-treated animals. The most striking immunological finding was the divergent cyto- kine trajectory between groups: HAG-treated rats showed declining serum IL-6 and IL-1β levels over time, whereas control rats exhibited increasing levels of both cytokines. This interaction suggests that HAG actively blunted the postoperative inflammatory surge. The sig- nificance of this cytokine modulation is substantial, as IL-6 and IL-1β are key drivers of both adhesion formation and the chronic inflam- matory state associated with endometriosis. IL-6, in particular, has been identified as an upstream mediator of peritoneal fibrosis: surgi- cal injury triggers IL-6 release, which in turn induces profibrotic me- diators such as TGF-β1, thereby promoting collagen deposition and dense adhesions [24]. Consistent with this mechanism, neutraliza- tion of IL-6 signaling has been shown to protect against adhesions. Uyama et al. [15] demonstrated that an anti-IL-6 receptor antibody markedly reduced neutrophil influx and adhesion scores in a mouse adhesion model. In the context of endometriosis, elevated IL-6 in le- sion microenvironments is thought to promote the survival and in- vasiveness of ectopic endometrial cells, thereby contributing to dis- ease persistence [25]. Notably, El-Zayadi et al. [ 26] reported that blocking IL-6 receptors in an experimental endometriosis model sig- nificantly reduced lesion size relative to untreated controls. Our find- ing that HAG treatment led to a decrease in IL-6 over time, whereas IL-6 increased in untreated rats, mirrors the effects of those IL-6-tar- geted interventions and underscores the cytokine-modulating ca- pacity of HAG. IL-1β is another proinflammatory cytokine that was reduced by HAG, with important implications for adhesion pathology. IL-1β has Figure 3. Cytokine changes during the study period between study groups. (A) Serum interleukin 6 (IL-6) levels over time in the human amniotic membrane gel (HAG) and control groups. (B) Serum IL-1β levels over time in the HAG and control groups. Data are presented as mean±standard deviation (SD). Table 3. Histopathologic assessment 3 weeks post-intervention in two study groups Histopathological features HAG Control p-value Presence of endometriosis 8 (36.4) 21 (95.5) < 0.001 Other pathological findings Fibrosis 4 (18.2) 7 (31.8) < 0.001 Abscess 3 (13.6) 13 (59.1) Adipose tissue reaction 15 (68.2) 2 (9.1) Values are presented as number (%). HAG, human amniotic membrane gel. IL-6 levels over time IL-1β levels over time HAG Control HAG Control Mean±SD Baseline BaselineBefore intervention time point Before intervention time point Post-intervention Post-intervention 2.75 2.50 2.25 2.00 1.75 1.50 1.25 1.00 3.25 3.00 2.75 2.50 2.25 2.00 1.75 1.50 Mean±SD https://doi.org/10.5653/cerm.2025.091106 Clin Exp Reprod Med [Epub ahead of print] AA BB long been implicated in postoperative adhesion formation because it stimulates mesothelial and inflammatory cells to release plasmino- gen activator inhibitors, thereby suppressing fibrin clearance and fa- cilitating the formation of permanent fibrous bands [13]. Neutraliza- tion of IL-1 in animal models results in significantly fewer adhesions, highlighting its role as a pro-adhesive mediator [13]. In endometrio- sis, IL-1β is abundantly expressed and appears to exacerbate the chronic inflammatory milieu. For example, Peng et al. [27] found that IL-1β directly upregulated nerve growth factor in endometriotic tis- sue, thereby driving local neurogenesis and pain, including deep dyspareunia, in affected women. By reducing IL-1β levels, HAG may therefore interrupt a vicious cycle of inflammation, nerve sensitiza- tion, and fibrosis that underlies endometriosis progression. Numerous studies have demonstrated that human amniotic membrane (HAM) can reduce tissue injury, inhibit fibrosis, and pre- vent postoperative adhesions through multiple molecular pathways. In particular, HAM may inhibit fibroblast proliferation and collagen accumulation through the TGF-β/Smad pathway, which plays a cen- tral role in fibrogenesis [28]. In addition, modulation of the nuclear factor-κB and signal transducer and activator of transcription 3 path- ways has been associated with reduced levels of proinflammatory cytokines such as IL-6 and IL-1β, thereby promoting tissue repair [29]. Moreover, regulation of matrix metalloproteinase 2 (MMP-2) and MMP-9 activity may help control extracellular matrix degradation in a manner that prevents fibrotic adhesion formation [4]. HAM may also inhibit abnormal neoangiogenesis through effects on vascular endothelial growth factor, which could help reduce the persistence of endometriotic lesions [30]. These molecular and cellular character- istics suggest that amniotic products such as amniotic membrane gel may have not only a preventive role but also a therapeutic effect on chronic lesions such as endometriosis. From a translational perspective, these findings suggest that HAG may serve as a valuable adjunct in endometriosis surgery by target- ing both the anatomical and inflammatory contributors to postoper- ative complications. Given its favorable safety profile in other clinical settings, HAG’s dual role as a physical barrier and anti-inflammatory agent may help reduce lesion recurrence and adhesion-related out- comes such as chronic pelvic pain and infertility. This study has several limitations. First, although the animal model is widely used, it does not fully replicate the cyclical hormonal envi- ronment or the complex immunological features of human endome- triosis. Second, although adhesion scores and cytokine levels were assessed, functional outcomes such as pain behavior and fertility were not evaluated. Third, additional cytokines beyond IL-6 and IL-1β could not be measured because of limited financial resources, which may have restricted a more comprehensive characterization of the inflammatory response. Although inclusion of a comparator anti-ad- hesion agent would have strengthened the analysis, no gold-stan- dard product currently exists for this specific application. Therefore, the study was designed to assess the efficacy of HAG as a standalone intervention. Finally, practical concerns such as product consistency and cost require further investigation. In conclusion, HAG reduced lesion size, adhesions, and proinflam- matory cytokine levels (IL-6 and IL-1β) in this experimental model. These findings support its potential to modulate both inflammatory and fibrotic pathways in endometriosis. Further long-term and clini- cal studies are warranted to confirm these benefits and to explore the integration of HAG into standard surgical care. Additional information 1 Endometriosis Research Center, Iran University of Medical Sciences, Tehran, Iran 2 Iranian Scientific Society of Minimally Invasive Gynecology, Tehran, Iran 3 Department of Surgery, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran 4 Smart University of Medical Sciences, Tehran, Iran 5 Department of Epidemiology, School of Public Health, Iran University of Medical Sciences, Tehran, Iran 6 Department of Pathology, Clinical Research Development Center, Shahid Modarres Educational Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran 7 University of British Columbia, Vancouver General Hospital, and BC Cancer. British Columbia’s Gynecological Cancer Research Team (OVCARE), Vancouver, BC, Canada 8 Department of Pharmacology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran 9 Pars Advanced and Minimally Invasive Medical Manner Research Center, Pars Hospital, Iran University of Medical Sciences, Tehran, Iran 10 Department of Biology and Anatomical Sciences, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran Conflict of interest No potential conflict of interest relevant to this article was reported. Acknowledgments The authors thank the Endometriosis Research Center, Iran Univer- sity of Medical Sciences. ORCID Roya Derakhshan https://orcid.org/0000-0001-7425-3412 Shahla Chaichian https://orcid.org/0000-0001-5772-8711 Author contributions Conceptualization: RD, SC. Methodology: RD, AM (Abolfazl Meh- www.eCERM.org 7 R Derakhshan et al. HAG and endometriosis adhesions dizadehkashi), SC, AM (Arash Mohazzab). Formal analysis: AM (Arash Mohazzab). Data curation: RD, BS, MGN. Funding acquisition: AM (Abolfazl Mehdizadehkashi). Project administration: AM (Abolfazl Mehdizadehkashi), SC. Investigation: RD, BS, MGN. Validation: AM (Arash Mohazzab), SR. Writing–original draft: RD, SC, AM (Arash Mo- hazzab). Writing–review and editing: RD, AM (Abolfazl Mehdizadeh- kashi), BS, SC, AM (Arash Mohazzab), BK, TN, MAS, SAZ, SR, BN, MGN. Approval of final manuscript: RD, AM (Abolfazl Mehdizadehkashi), BS, SC, AM (Arash Mohazzab), BK, TN, MAS, SAZ, SR, BN, MGN.

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