Effects Of Lycopene Supplementation On The Oxidative Damage Induced By Exhaustive Exercise In Rats

Exhaustive exercise is known to cause oxidative stress and various kinds of cell and tissue damage through the generation of reactive oxygen species. Thus, oxidative stress had been associated with decreased physical performance, muscular fatigue, muscle damage and overtraining. Recently, many studies showed that exhaustive exercise resulted in the enhanced accumulation oxidative by-products of lipid peroxidation, decreased total antioxidant capacity, oxidative damage of cellular DNA and acute elevation nitrite/nitrate (NO_X) content. Beside, oxidative stress also induced inflammatory responses that activated neutrophils and myeloperoxidase (MPO) activity. Therefore, nutritionists suggest that antioxidant supplementation may result in a decreased oxidative damage and an improved immune function. Lycopene, a kind of red-colored carotenoids, has previously been shown to have high antioxidant activity. It can scavenge the free radical directly, improve the immune system and modulate metabolic pathways of the body. Furthermore, recent studies also found that dietary intakes of tomatoes and tomato products containing lycopene are associated with decreased risk of chronic diseases such as cancer and cardiovascular diseases in numerous recent studies. However, in the sport science study, effects of lycopene supplementation on exercise are still not clear.In the present study, we investigated the effects of lycopene supplementation at a low dose (which is equivalent to an intake of 25 mg/day in humans) and a high dose (which is equivalent to 75 mg/day in humans) on antioxidant capacity in rats during exhaustive exercise. Forty-eight adult male Sprague-Dawley (SD) rats will randomly divided into the following six groups: control (C), low-dose lycopene (CLL), high-dose lycopene (CHL), exhaustive exercise (E), exhaustive exercise with low-dose lycopene(ELL) and exhaustive exercise with high-dose lycopene (EHL) groups. After 30 days, the final results revealed that exercise group rats performed an exhaustive running test on a motorized treadmill at a final speed of 30 m/min, 10% grade, approximately 70-75% VChmax. We will determine antioxidant enzymes activities, such as glutathione peroxidase (GPX), glutathione reductase (GRD), superoxide dismutase (SOD), and catalase (CAT), antioxidant concentrations, e.g. glutathione (GSH), and malondialdehyde (MDA) levels, the marker of extent of lipid peroxidation, in blood and muscle samples. Also, we will examine xanthine oxidase (XO) and phagocytic activity of neutrophils, MPO, in muscle.Results showed that XO activities of plasma and muscle, and muscular MPO activity in group E were significantly increased compared with group C. Compared to group E, the elevations of XO and MPO activities of muscle were significantly decreased in group EHL. The MDA concentrations of plasma and muscle in group E were significantly increased by 72% and 114%, respectively, than in group C. However, this was prevented in rats treated with a low-dose or a high-dose lycopene before exercise. There was no significant difference in the GSH concentrations of erythrocytes among each group. But, exhaustive exercise resulted in a significant decrease in GSH content of muscle. Obviously, lycopene does protect muscle tissue after exhaustive exercise from oxidation.