BACKGROUND:
Performing high intensity or exhaustive exercise can lead to muscle damage such as injuries, chronic fatigue and overtraining, partly due to the high synthesis of reactive oxygen species. The α-lipoic acid (ALA) and its reduced form, dihydrolipoic acid, act as potent antioxidant and eliminate free radicals. Although this response depends on the type of exercise and supplementation, animal and human studies have shown the benefits of antioxidant supplementation on the recovery of damages caused by exhaustive exercise, either by restoring antioxidant levels or by decreasing the damage.
OBJECTIVE:
We evaluated the effect of ALA supplementation on muscular biomarkers of oxidative stress following exhaustive exercise of trained mice.
METHODS:
Sixty mice were trained to swim for 6 weeks. On the last week, half of the animals were supplemented daily with 100 mg/kg of oral gavage of ALA in soy oil as a vehicle. The other half received just the vehicle. On the last day 20 animals from each group were submitted to an exhaustion protocol with 10% overweight attached to tail. Animals were euthanized on 3 moments: basal, just after the exhaustive protocol (0 h) and, 4 h after the exhaustive protocol. The gastrocnemius muscle was promptly excised and homogenized. The homogenates were used to estimate oxidative stress biomarkers.
RESULTS:
There was a simultaneous decrease of non-protein thiols and vitamin E after 4 h of exhaustive exercise in the ALA group (p<0.05) compared to the control group, suggesting the consumption of these compounds in the process of lipid peroxidation. Interestingly, there was an increase of nitrate and nitrite in ALA group (p<0.05) and a decrease in the control (p<0.05) compared to basal moment, possibly by activation of endothelial nitric oxide synthase. The total antioxidant capacity remained unchanged in the ALA group.
CONCLUSION:
The supplementation with ALA resulted in a protection against oxidative stress caused by exhaustive exercise.
KEYWORDS:
Alpha-Lipoic acid; Antioxidants; Oxidative stress; Exercise
