Objectives: The aim of this study was to investigate the effects of both regular swimming training and vitamin E supplementation on the thioredoxin system, one of the key player in defense against oxidative stress. In order to examine the effects of regular physical exercise on the antioxidant defenses of tissues and on their susceptibility to damage induced by exercise, the activity of thioredoxin reductase (TrxR) have been determined.
Materials and Methods: Four groups of male rats were used. Two groups were trained to swim for nine weeks. One trained and one sedentary group received vitamin E supplementation for four days a week.
Results: Thiobarbituric acid-reacting substance (TBARS) levels of the trained group significantly decreased (p<0.01) in the liver and the brain. Meanwhile, both regular exercise and vitamin E supplementation caused increases (p<0.001) in TrxR activities in all tissues.
Conclusion: These results suggest that increased activity of TrxR is an important oxidative response of the thioredoxin system and plays an important protection role against protein damage. It is also likely that vitamin E depletion in oxidative stress may require recycling process of this molecule in relation to TrxR, supporting with the TrxR activities of tissues in both trained and vitamin E-supplemented group.