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

We tested the hypothesis that zinc deficient animals would be characterized by an increased sensitivity to cadmium-induced oxidative damage to the tes tes. Weanling male rats were given free access to either a control (25 mu g Zn/g) or a zinc deficient (0.5 mu g Zn/g) diet; or restricted access to th e 25 mu g Zn/g diet at a level of intake similar to that of rats fed the 0. 5 mu g 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 w ere higher in the cadmium-injected rats than in the saline-injected rats. T he extent of hemorrhages, as indicated by high hemoglobin and testes iron c oncentrations was higher in the cadmium-treated zinc deficient group than i n the cadmium-injected controls. In the zinc-deficient group, cadmium injec tion was associated with higher levels of lipid peroxidation (33% higher TE ARS content) and protein oxidation (17% lower glutamine synthetase activity ). Cadmium injection did not influence these parameters in the zinc-adequat e 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 susc eptibility of testes to cadmium-mediated free radical damage. (C) 1999 Publ ished by Elsevier Science Ireland Ltd. All rights reserved.