Exposure to Cadmium Impairs Sperm Functions by Reducing CatSper in Mice.

Cadmium (Cd), a common environmental heavy metal and endocrine disruptor, is known to exert toxic effects on the testes. However, the mechanisms accounting for its toxicity in mature spermatozoa remain unclear. Adult male C57BL/6 mice were orally administered with CdCl2 for 5 weeks at 3 mg·kg-1·day-1. Additionally, mouse spermatozoa were incubated in vitro with different doses of CdCl2 (0, 10, 50, 250 µM). Several sperm functions including the sperm motility, viability and acrosome reaction (AR) ratio were then examined. Furthermore, the current and expression levels of both the sperm-specific Ca2+ channel (CatSper) and the sperm-specific K+ channel (KSper) were evaluated by patch-clamping and western blotting, respectively. Our data showed that the motility, viability and AR of sperm exposed to cadmium significantly decreased in vivo and in vitro. Interestingly, these changes were correlated with changes in CatSper but not KSper. The findings indicate sperm dysfunction during both chronic and acute cadmium exposure as well as a specific role for CatSper in the reproductive toxicity of cadmium.