Cadmium inhibits mouse sperm motility through inducing tyrosine phosphorylation in a specific subset of proteins

Cadmium (Cd) has been reported to impair male fertility, primarily by disrupting sperm motility, but the underlying molecular mechanism remains unclear. Here we investigated the effects of Cd on sperm motility, tyrosine phosphorylation, AMP-activated protein kinase (AMPK) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity, and ATP levels in vitro. Our results demonstrated that Cd inhibited sperm motility, GAPDH activity, AMPK activity and ATP production, and induced tyrosine phosphorylation of 55-57 KDa proteins. Importantly, all the parameters affected by Cd were restored to normal levels when incubated with 10 μM Cd in the presence of 30 μM ethylene diamine tetraacetic acid (EDTA). Interestingly, changes of tyrosine phosphorylation levels of 55-57 KDa proteins are completely contrary to that of other parameters. These results suggest that Cd-induced tyrosine phosphorylation of 55-57 KDa proteins might act as an engine to block intracellular energy metabolism and thus decrease sperm motility.