Regression of experimental endometriotic implants in a rat model with the angiotensin II receptor blocker losartan

Aim Endometriosis is a common disease in women of reproductive age, and many different treatments have been developed, although none has provided a cure. In this study, the efficacy of losartan, an angiotensin II type 1 receptor blocker and an antiangiogenic and anti‐inflammatory agent, on regression of experimental endometriotic implants in a rat model was investigated. Methods Peritoneal endometriosis was surgically induced in 16 mature female S prague– D awley rats. The peritoneal endometriotic implant was confirmed after 28 days, and the animals were divided randomly into two groups. The control group ( n  = 8) was given 4 mL/day tap water by oral gavage, and the losartan group ( n  = 8) was given 20 mg/kg per day losartan p.o. We compared endometriotic implant size, extent and severity of adhesion, as well as plasma and peritoneal lavage fluid cytokine levels including vascular endothelial growth factor ( VEGF ) and tumor necrosis factor ( TNF )‐α, plasma inflammatory factor pentraxin‐3 ( PTX ‐3) and C ‐reactive protein ( CRP ) between the treatment groups. Results Mean surface endometriotic area, histological score of implants, adhesion formation, plasma VEGF , TNF , PTX ‐3 and CRP levels were significantly lower in the losartan group compared with control ( P  < 0.05). Furthermore, the peritoneal VEGF level was lower in the losartan group than in the control group ( P  < 0.001), but peritoneal TNF ‐α was similar in both groups ( P  > 0.05). Conclusion Losartan suppressed the implant surface area of experimental endometriosis in rats and reduced the levels of plasma VEGF , TNF ‐α, PTX ‐3 and CRP .