Perinatal Exposure Of Male Mice To Bisphenol A Affects Sperm Parameters And The Expression Of Testicular Sertoli Cell Junctional

Objective: To investigate the mechanism of bisphenol A inducing infertility by observing the effects of different concentrations of BPA on sperm parameters and the expression of testicular sertoli cell junctional proteins(Cx43, Occludin and N-cadherin) in adulthood. Methods: Pregnant mice were randomly divided into a control group and three experimental groups(2mg/kg, 20mg/kg, 200mg/kg BPA)after confirmed pregnancy by Yaginal Smear Test. Pregnant mice were gavaged with 0, 2, 20, 200 mg BPA/ kg body weight/ day from gestation day 12 to postnatal day 21. Those male mice were subsequently sacrificed on postnatal day 80. The changes of sperm parameters in the left cauda epididymis were determined. Histopathological changes in left testis were observed by HE staining and the expression of testicular sertoli cell junctional proteins(Cx43, Occludin and N-cadherin) were analysed by immunohistochemistry. The expression of testicular sertoli cell junctional proteins(Cx43, Occludin and N-cadherin) in right testis were analysed by western blotting analysis. Results: The sperm counts showed a dose-dependent decrease in groups exposed to BPA from(146.68±8.67) ×106in 2mg group to(112.42±12.45) ×106 in 200 mg group through(136.10±8.75) in 20 mg group. Consistent with reduced sperm counts, BPA treatment induced a significant decrease in sperm motility compared to the control in a dose-dependent manner. We observed normal seminiferous tubules that different spermatogenetic cells embedded in an orderly sequence, mature sperm rather than germ cells presented in the lumen in the control group. There were fewer mature sperms in the lumen of seminiferous tubules from 2 mg/kg BPA group compared to control. Sloughing of germ cells was observed in the lumen of seminiferous tubules from 20 mg/kg BPA group and 200 mg/kg BPA group. In addition, 200 mg/kg BPA group reveals structure disturbance of seminiferous tubules. Reductions in the expression of testicular sertoli cell junctional proteins(Cx43, Occludin and N-cadherin) were observed by immunohistochemistry and western blotting analysis.Conclusions: The perinatal exposure of BPA leads to reductions in the expression of testicular sertoli cell junctional proteins. We infer that BPA impair spermatogenesis by altering the expression of testicular sertoli cell junctional proteins.