Resumen de Effects of [alpha]-lipoic Acid on mtDNA Damage after Isolated Muscle Contractions.
Mark C. Fogarty, Giuseppe Devito, Gareth W. Davison, Ciara M. Hughes, George W. Burke, Conor Mcclean, John C. Brown, Jane McEneny, David Brown
AB Introduction: Although pharmacological antioxidants have previously been investigated for a prophylactic effect against exercise oxidative stress, it is not known if [alpha]-lipoic acid supplementation can protect against DNA damage after high-intensity isolated quadriceps exercise. This randomized controlled investigation was designed to test the hypothesis that 14 d of [alpha]-lipoic acid supplementation can attenuate exercise-induced oxidative stress. Methods: Twelve (n = 12) apparently healthy male participants (age = 28 +/- 10 yr, stature = 177 +/- 12 cm and body mass = 81 +/- 15 kg) were randomly assigned to receive either a daily supplement of 1000 mg of [alpha]-lipoic acid (2 x 500-mg tablets) for 14 d (n = 6) or receive no supplement (n = 6) in a double-blinded experimental approach. Blood and muscle biopsy tissue samples were taken at rest and after the completion of 100 isolated and continuous maximal knee extension (minimum force = 200 N, speed of contraction = 60[degrees][middle dot]s-1). Results: Exercise increased mitochondrial 8-hydroxy-2-deoxyguanosine (8-OHdG) concentration in both groups (P < 0.05 vs rest) with a concomitant decrease in total antioxidant capacity (P < 0.05 vs rest). There was a marked increase in blood total antioxidant capacity after oral [alpha]-lipoic acid supplementation (P < 0.05 vs nonsupplemented), whereas DNA damage (Comet assay and 8-OHdG), lipid peroxidation, and hydrogen peroxide increased after exercise in the nonsupplemented group only (P < 0.05 vs supplemented). Exercise increased protein oxidation in both groups (P < 0.05 vs rest). Conclusions: These findings suggest that short-term [alpha]-lipoic acid supplementation can selectively protect DNA (but not in muscle mitochondria) and lipids against exercise-induced oxidative stress
