Intense muscle contraction induced by physical exercise increases the production of reactive oxygen species, which causes oxidative stress in several organs, such as the liver and the heart. Physical training may increase antioxidative defenses and decrease oxidative stress. However, it is not clear what training frequency improves oxidative stress parameters. This study evaluated the effect of training two and three times a week on oxidative stress biomarkers in the liver and the heart. Eighteen young male mice (CF1) weighing 30 to 35 g were divided into three groups (n=6): no training (NT); twice a week training (T2); and three times a week training (T3). The training program lasted eight weeks, and the animals were killed 48 hours after the last training session. The liver and the heart were removed and stored at -70o C. The following analyses were conducted: thiobarbituric acid reactive substances, protein carbonylation, total thiol content, superoxide dismutase, catalase and glutathione peroxidase. Oxidative damage was reduced only in the T3 group, and there was an increase in total thiol content, supeoxidase dismutase and catalase in T3 when compared with the NT group. Glutathione peroxidase was not significantly different between groups. Only training three times a week seemed to reduce oxidative stress and increase the efficiency of the antioxidant system in mice.
Antioxidant enzymes; Oxidative damage; Physical exercise; Training frequency
