Oxidative stress in testes of rats subjected to chronic iron intoxication and alpha-tocopherol supplementation.

Oxidative stress parameters were evaluated in rat testes after chronic iron intoxication and vitamin E supplementation. Male Wistar rats were fed during 6 weeks with the following diets: C = rat chow; I = C + 25 mg carbonyl-iron/g diet; A = C + 0.2 mg alpha-tocopheryl acetate/g diet; and the combination of I and A (IA). After the treatment, no changes in final body weight, testis weight and protein content were observed. Total iron content in testes from the I group was 33% higher compared to the C group (216 +/- 10 nmol/g of tissue). The content of alpha-tocopherol (alphaT) was 2.5-fold higher in the A and IA groups compared to the C group (12.8 +/- 0.7 nmol/g tissue). The content of ubiquinol-9 (13.0 +/- 1.7 nmol/g tissue) and ubiquinol-10 (3.3 +/- 0.5 nmol/g tissue) was similar among the groups. Superoxide dismutase activity was 13 and 16% lower in the A and IA groups with respect to the C group (12.9 +/- 0.7 U/mg protein). Catalase activity was 26 and 33% lower in the I and IA groups than in the C (0.19 +/- 0.01 pmol/mg protein) and A (0.21 +/- 0.01 pmol/mg protein) groups, respectively. Glutathione peroxidase was 24 and 23% higher in the IA group than in the C (11.4 +/- 0.3 mU/mg protein) and I (11.5 +/- 1.0 mU/mg protein) groups, respectively. The testes content of 2-thiobarbituric acid-reactive substances (TBARS) and protein-associated carbonyl groups were 37 and 16% higher, respectively, in the I group than in the C group. These increased in TBARS and carbonyls, were not observed in the IA group. No diet-associated changes were observed in the steady state levels of 8-oxo-2'-deoxyguanosine in testes DNA (4.2 +/- 0.2 residue/10(5) dG). The present data suggest that this model of chronic iron overload produced a mild oxidative damage in rat testes that was partially prevented by alphaT supplementation.