Oxidant Defense Systems in Testes from Zinc-Deficient Rats

Abstract

Previous studies have demonstrated that zinc deficiency can be associated with high rates of oxidative damage to testes lipids, proteins, and DNA in male rats. In the present work, different aspects of the oxidant defense system (enzymes and lipidsoluble antioxidant substances) were characterized in the testes of control and zinc-deficient rats. Seventeen-day-old males were given free access to either a control (25 μg Zn/g) or a zinc-deficient (0.5 μg Zn/g) diet, or the 25 μg Zn/g diet at a level of food intake similar to that of zinc-deficient rats. Animals were sacrificed 14 days after the initiation of the diet. The activities of copper-zinc superoxide dismutase (CuZn SOD) and glutathione reductase (GRed) were significantly higher (34% and 23%, respectively) in testes from the zinc-deficient animals than in those of the ad libitum controls. In testes, the activities of manganese superoxide dismutase (Mn SOD) and glutathione peroxidase (GPx), and the concentration of α-tocopherol and ubiquinol-9 and −10 were similar among the groups. However, the ratio of reduced/total concentration of both ubiquinols was higher in the zinc-deficient and restrict-fed animals than in the ad libitum controls. Testes homogenates from the zinc-deficient rats showed a low susceptibility to Fe (II)-induced oxidation, which could be explained in part by a lower peroxidation index, mainly due to the decreased testicular content of the fatty acid 20:4 observed in these animals. In summary, both undernutrition and zinc deficiency can cause an oxidative stress situation in testes, for which cells tend to compensate by increasing select components of the oxidant defense system.