Effect of imatinib on growth of experimental endometriosis in rats

Abstract Objective Currently, medical and surgical treatment options for endometriosis are limited due to suboptimal efficacy, and also safety and tolerance issues. Long-term use of gonadotrophin-releasing hormone analogs, androgenes, and the danazol, which are widely used drugs for endometriosis, is usually not possible due to their suboptimal safety and tolerance profile. The lack of an effective, tolerable and safe treatment option for endometriosis makes animal models of experimental endometriosis necessary to study candidate drugs. The aim of this study was to investigate the efficacy of imatinib on the experimental endometriosis in a rat model. Study design Endometriosis was induced by autotransplantation of uterine tissue into the peritoneal cavity. Twenty-four rats, which had visually confirmed endometriotic implants on subsequent laparotomy, were randomized into three groups to receive imatinib (25 mg/kg/day, p.o.), anastrozole (0.004 mg/day, p.o.), or normal saline (0.1 mL, i.p.) for 14 days. After removal of endometriotic tissue and H & E staining, endometriosis score was determined according to a semiquantitative histological classification. Also, immunostaining with primary antibodies including VEGF, CD117, and Bax were used for immunohistochemical (IHC) examination. Results Both anastrozole and imatinib suppressed the growth of endometriotic tissue and reduced the number of ovarian follicles. Although the difference was not statistically significant, imatinib was less effective than anastrozole for treatment of endometriosis. Conclusion Imatinib effectively treats experimental endometriosis by its inhibitor effects on angiogenesis and cell proliferation.