Alpha-tocopherol may protect hepatocytes against oxidative damage induced by endurance training in growing organisms

Abstract

Background. Training-induced oxidative stress can be reduced by α-tocopherol. Adequate intake of α-tocopherol could have health benefits for previously untrained young subjects. Objectives. The aim of this study was to determine the effects of training and different doses of α-tocopherol on exercise-induced oxidative stress in rat livers. Material and Methods. Young male Wistar rats (n = 40) were randomly divided into eight groups (undergoing training and not undergoing training, given orally administered α-tocopherol doses of 0, 0.5, 1.0 and 4.0 mg). Every day for 10 consecutive days, the rats in the training groups ran for 15 min on a treadmill at 20 m/min to induce oxidative stress. Hepatic oxidative stress was evaluated based on the liver concentrations of 8-hydroxy-2′-deoxyguanosine (8-OHdG) and thiobarbituric acid reactive substances (TBARS). Results. The liver concentrations of α-tocopherol were significantly influenced by α-tocopherol doses (p < 0.001) and physical exercise (p < 0.001). The liver concentrations of α-tocopherol increased in response to the highest dose (4 mg/d) of α-tocopherol in the non-training groups. In the training groups, the liver concentrations of α-tocopherol were independent of the dose. The levels of TBARS, a marker of lipid peroxidation, were lowest in the training and non-training rats administered 4.0 mg of α-tocopherol. Physical exercise and α-tocopherol doses significantly influenced TBARS concentrations (p = 0.004, p < 0.05). Conclusions. The results of this study indicate that running training causes lipids peroxidation and reduces α-tocopherol levels in the liver, but it does not contribute to DNA damage. Increased liver concentrations of α-tocopherol were found to exert a protective effect against oxidative damage induced by endurance training. An adequate intake of α-tocopherol is important for previously untrained young subjects.