Bisphenol A Impairs Mature Sperm Functions by a CatSper-Relevant Mechanism

Bisphenol A (BPA), an endocrine-disrupting chemical, is widely used in the manufacture of daily necessities. Previous studies showed that BPA could impair spermatogenesis. However, its effects on mature spermatozoa are not well known. We aimed to investigate the in vivo and in vitro toxicity of BPA on mature mouse spermatozoa. Different doses of BPA (0, 10, 50, and 250 μg·kg(-1)·d(-1)) were administrated orally to C57BL/6 mice for 8 weeks. Subsequently, the sperm viability, motility, acrosome reaction (AR) ratio together with the expression/current levels of the sperm-specific Ca(2+ )channel (CatSper) and K(+ )channel (KSper) were examined. These parameters were also evaluated after applying BPA directly to normal mouse sperm to appraise the toxicity of BPA to mature sperm in vitro Significant decreases in sperm motility and AR were found in BPA administrated mice, possibly resulting from a BPA caused CatSper down-regulation which was supported by both western blot and patch clamping results. Moreover, direct application of BPA to spermatozoa inhibited CatSper transiently and also caused significant reductions in sperm total motility and AR ratio. In conclusion, both in vivo administration and in vitro application of BPA impair mature sperm functions by a CatSper-relevant mechanism.