OBJECTIVETo investigate the effect of Chinese herbs for nourishing Shen-yin and removing Xiang-fire (NYRF) on estrogen receptor (ER) expression in uterus and ovary of rats contaminated with nonylphenol (NP) or its bisphenol A (BPA) mixture, for exploring the action mechanism of NYRF in antagonizing the estrogen-mimetic activity of environmental endocrine disruptors (EEDs).

METHODSEEDs contaminated female SD rats, 3-week old, were divided into two groups, the treated group fed with NYRF and the control group with corn oil during the same period of contaminating for 15 days. The wet weight (WW) and organ coefficient (OC) of uterus in rats, as well as the ER protein and mRNA expressions in rat's uterus and ovary were detected and compared.

RESULTSAs compared with normal range, WW and OC increased significantly in the contaminated rats of the control group, with significantly down-regulated ER protein expression in uterus, and expressions of ER alpha and ER beta gene and protein in ovary (P<0.05). While in the treated group, the above-mentioned abnormalities of various indicators were markedly reversed to a certain extent (P<0.05).

CONCLUSIONEEDs show estrogenic-mimetic action on productive organs, which could be antagonized by NYRF, resulting in the down-regulated mRNA and protein expressions of ER in reproductive organs, so as to reduce the sensibility of reproductive organs to EEDs, which is probably one of the acting mechanisms of NYRF.