Effect of BCG vaccine on endometriotic implants in a rat model of endometriosis

Objective: To investigate the effect of BCG vaccine on peritoneal implantation of endometrial tissue in rats and the possible mechanism.Methods: Forty sexually mature virgin Wistar albino rats were used to establish the rat model of endometriosis.The established model rats were randomly assigned to three groups.The rats were treated with ip injection of 0.1 mL BCG,or intradermal injection of 0.1 mL BCG,or ip and intradermal injection of 0.1 mL saline(control).All the rats underwent laparotomy 4 weeks after injection.The implanted segments were excised,volume of the segments was measured,the macrophages in the peritoneal cavity were counted,and CD+_3 cells and CCR+_5 cells were determined by immunohistochemisty.Results: The volume of the segments was significantly decreased(P0.05) after ip or intradermal injection of BCG as compared to control group;ip injection was more effective than intradermal injection.The number of macrophages was significantly increased(P0.05) after ip or intradermal BCG injection as compared to control group.The numbers of CD+_3 cells and CCR+_5 cells were significantly larger in ip BCG group than in intradermal BCG and control groups(P0.05).Conclusions: The ip injection of BCG is more effective than intradermal injection in inhibiting ectopic endometriotic implants;this may be duo to potentiate immune responses in the peritoneal cavity.