Regression of endometrial autografts in a rat model of endometriosis treated with etanercept.

Objective: To determine the efficacy of anti-tumor necrosis factor therapy (etanercept) for treating endometriosis in the rat endometriosis model.

Study Design: A randomized, placebo-controlled, blinded study using rat endometriosis model. After the peritoneal implantation of endometrial tissue, twenty-eight Wistar female rats were randomized to two equal intervention groups: the control group and the etanercept-treated group. After measuring implant volume, pretreatment blood and peritoneal fluid samples were obtained. A vehicle treatment of 2 mL saline to the rats in control group and 0. 4 mg/kg etanercept SC once weekly were administered in the etanercept-treated group. After four weeks treatment period, the volumes and histopathological properties of the implants were evaluated. A scoring system was used to evaluate preservation of epithelia. Endometrial explants were evaluated immunohistochemically for tumor necrosis factor receptor type 2 (TNFR2). A scoring system was used to evaluate expression grade of TNFR2.

Results: There was not a significant difference in spherical volume between control (131.0 (60.3-501.2)) and treatment groups (72.8 (31.2-149.6)) (p>0.025). There was a significant change in between the volumes of implants before and after treatment in etanercept group (p<0.05). At the end of the treatment significant differences among the groups were found in histopathological and immunohistochemical parameters (p<0.05) also histologic scores and HSCORES were decreased in the treatment group significantly (p<0.05).

Conclusion: These results indicate that etanercept was found to effectively reduce the development of endometriosis in this experimental rat model.