Bisphenol a influences blastocyst implantation via regulating integrin β3 and trophinin expression levels.

OBJECTIVE This study is to investigate effects of bisphenol A (BPA) on the blastocyst implantation in endometrium. METHODS Pregnant mice were orally administered with BPA. Implantation sites were examined, and serum estrogen level was assayed with ELISA. Protein expression levels were detected with immunohistochemistry and immunofluorescence staining. RESULTS High doses (400 and 600 mg/kg/day) of BPA remarkably reduced the implantation sites in the pregnant mice. No significant differences were observed in the serum estrogen level across the groups. Moreover, high doses (400 and 600 mg/kg/day) of BPA significantly declined the expression level of endometrial estrogen receptor α (ERα) in the pregnant mice. In addition, high doses (400 and 600 mg/kg/day) of BPA significantly declined the expression levels of integrin β3 and trophinin in the endometrium and blastocysts. CONCLUSION BPA declines ERα expression in endometrium, and inhibits adhesion protein expression in endometrium and blastocysts, causing the adhesion failure of blastocyst implantation.