Effect of estrogen receptor β on the formation of mice endometriosis

Objective To investigate the effect of estrogen receptor β(ER-β)on the formation of mice endometriosis.Methods Endometriosis animal model was established with 30 ER-β knockout(βERKO)mice and 22 ER-β non-knockout(βER)mice.All the mice were divided into three groups:intact group(βERKO 10 and βER 8),ovariectomy group(βERKO 10 and βER 7)and ovariectomy + estradiol treatment group(βERKO 10 and βER 7).The endometriotic grafts were taken out from all the mice 2 weeks after operation,and the weight,histological structure and the expression of MMP-9 in the grafts were analyzed and compared between βERKO and βER mice.Results The endometriotic grafts were significantly heavier 2 weeks after transplantation than that before transplantation in intact group(P0.05),and were lighter than that before transplantation in ovariectomy group(P0.05),but no significant difference was found before and 2 weeks after transplantation in ovariectomy + estradiol treatment group(P0.05).In addition,no significant differences were found between the βERKO and the βER mice in endometriotic grafts' weight,the histopathologic structure and the expression of MMP-9.Conclusion ER-β may throw few influence on the formation of endometriosis.