Effect on ovulation of surgically induced endometriosis in rabbits

To study the effect of endometriosis on follicular rupture, endometrial tissue was autografted to New Zealand White rabbits. Endometrium was surgically implanted into the peritoneal cavity or into the rectus muscle. Human chorionic gonadotropin was administered to induce ovulation. During three subsequent laparotomies, the number of corpora lutea and stigmata were counted. The viability of the implants was demonstrated histologically. Ovaries were removed during the last laparotomy and ovarian serial sections were examined. In rabbits with peritoneal induced endometriosis, the percentage of stigmata/corpora lutea was significantly decreased. Macroscopic study was confirmed by histological examination. Indeed, a high incidence of entrapped oocytes was found in rabbits with peritoneal endometriosis. Extraperitoneal endometriosis had no effect on ovulation. Our data demonstrated that endometriosis induced a failure of follicular rupture. After endometriumectomy, no failure to ovulate was observed, suggesting that the effect of endometriosis on the ovulation disappeared with excision of endometrial implants.