Cadmium-induced testes oxidative damage in rats can be influenced by dietary zinc intake

Abstract

We tested the hypothesis that zinc deficient animals would be characterized by an increased sensitivity to cadmium-induced oxidative damage to the testes. Weanling male rats were given free access to either a control (25 μg Zn/g) or a zinc deficient (0.5 μg Zn/g) diet; or restricted access to the 25 μg Zn/g diet at a level of intake similar to that of rats fed the 0.5 μg Zn/g diet. After 14 days on the diets, animals were injected sc with either saline or CdCl2 (2 mg Cd/kg body weight) solutions, and killed 24 h later. In the zinc-deficient group, testes weight and testes/body weight were higher in the cadmium-injected rats than in the saline-injected rats. The extent of hemorrhages, as indicated by high hemoglobin and testes iron concentrations was higher in the cadmium-treated zinc deficient group than in the cadmium-injected controls. In the zinc-deficient group, cadmium injection was associated with higher levels of lipid peroxidation (33% higher TBARS content) and protein oxidation (17% lower glutamine synthetase activity). Cadmium injection did not influence these parameters in the zinc-adequate groups. Extracellular superoxide dismutase activity was lower in the zinc-deficient group than in the zinc-sufficient groups; there was a trend (P<0.06) for a lower activity in the cadmium- versus the saline-injected rats. These results support the concept that zinc deficiency increases the susceptibility of testes to cadmium-mediated free radical damage.