Evaluation of involvement of testicular metallothionein gene expression in the protective effect of zinc against cadmium-induced testicular pathophysiology in rat.

To investigate the effects of exposure to Cd and Zn on testicular MT-1 and MT-2 gene expression and evaluate their involvement in Zn protection against Cd-induced testicular pathophysiology, male rats received either tap water, Cd or Cd+Zn in their drinking water for 35 days. Cd induced histopathological changes in testicular tissues were accompanied by decreased plasma testosterone level, plasma and testicular Zn concentrations, oxidative stress, and by increased MT-1 and MT-2 gene expression. Co-treatment with Cd and Zn reversed the Cd-induced decrease testosterone level and SOD activity, decreased testicular Cd accumulation and partially restored Cd-induced histological changes, lipid peroxidation, and Zn depletion. The increase of testicular MT-1 and MT-2 gene expression under Cd influence was significantly reduced in Cd+Zn group. These data suggest that Zn enhances the protection against Cd-induced testicular pathophysiology through non-MT gene expression mechanisms but essentially by preventing Cd accumulation, Zn deprivation and by ameliorating the testicular antioxidant status.