OBJECTIVETo explore the effect of Xiaochaihu Decoction (XCHD) on ectopic endometrium in rats with endometriosis and its mechanism.

METHODSThe rat model of endometriosis was established and rats were divided into 5 groups, the low dosage of XCHD group (5 g x kg(-1) x d(-1) , n = 10) , the medium dosage of XCHD group (10 g x kg(-1) x d(-1), n =10), the high dosage of XCHD group (15 g x kg(-1) x d(-1), n = 10) , the danazol group(0. 1 g x kg(-1) x d(-1), n =9) and the control group(20 ml x kg(-1) x d(-1) distilled water, n = 10). After treated for four successive weeks, the effect of XCHD on ectopic endometrium was evaluated by observing the changes in transmission electron microscopy. Fas and Caspase-3 protein expression in endometrium and endometriotic tissue were observed by immunohistochemistry method.

RESULTSEctopic endometrial growth was markedly inhibited (P < 0. 05 or P < 0. 01) in all the XCHD groups; Fas and Caspase-3 protein expressions of ectopic endometrial tissue were higher than those in the endometrium.

CONCLUSIONXCHD could inhibit the growth of the ectopic endometrium in rats with experimentally induced endometriosis. The therapeutic mechanism may be related to promoting the apoptosis in ectopic endometrial tissue by increasing Fas protein expression.