Oxidative stress in the brain of reproductive male rats during aging

Reproduction alters the male physiology. We performed a comprehensive study to examine oxidative stress in the brains of male rats with (experienced) or without (naïve) reproductive activity during aging. Oxidative stress was assessed by measuring the activity of catalase, glutathione peroxidase, superoxide dismutase, glutathione S-transferase, aconitase, and aconitase reactivated, and by measuring lipid peroxidation, protein carbonylation, nitrite and nitrate levels, vitamin C levels, and glutathione (total, reduced, oxidized forms) levels in brain tissue, as well as testosterone and estradiol levels in serum. Reproductively active animals exhibited increased testosterone levels and aconitase activity, suggesting an increased metabolism. Increased antioxidant enzyme activities and increased levels of antioxidant compounds were observed, yet damage to biomolecules was also observed in experienced rats. During aging changes in oxidative stress were observed. We found higher activities of antioxidant enzymes, higher amounts of antioxidants, and more damage at six months of age among experienced animals than among naïve animals. Similar antioxidant activities and levels, and damage were found between the groups at twenty-four months of age. These results add comprehensive data regarding changes in oxidative stress during aging, and suggest an explanation for the costs of reproduction.