Effect of Different Therapeutic Regimens of Mifepristone on the Expression of Metalloproteinase-9 and Tissue Inhibitor of Metalloproteinase-1 in Endometriotic Rats

Objective To evaluate the effect of different dosage and different treatment time of mifepristone on the expression of metalloproteinase 9(MMP-9) and tissue inhibitor of metalloproteinase 1(TIMP-1) in ectopic endometrium in rats.Methods Sixty-five endometriotic rats were randomly divided into three groups: the control group and the mifepristone groups(including low dose and high dose groups).Twenty days,30 days and 40 days after gastrogavage,all rats were killed and tissues of ectopic endometrium were removed for detecting MMP-9 and TIMP-1.Results The expression of MMP-9 decreased and the expression of TIMP-1 increased in the mifepristone groups(P0.05).This phenomenon in the high dose group was more significant than that in low dose group.The expression of TIMP-1 was the highest in the mifepristone groups after 30 days(P0.05),and the ratio between MMP-9 and TIMP-1 was lower than 1.Conclusions The treatment with mifepristone can reduce the invasiveness of ectopic endometrium in rats,especially in the high dose group.Mifepristone can decrease the invasiveness of ectopic endometrium most significantly 30 days after the treatment.It is useless to prolong treatment time for reducing the invasiveness of the rats' ectopic endometrium.