Oxidative stress on mitochondrial antioxidant defense system in the aging process:: Role of DL-α-lipoic acid and L-carnitine

Background: Oxidative damage is hypothesized to accumulate throughout the lifetime of an organism, eventually giving rise to aging. The mitochondria may be the primary cellular source and target of endogenous ROS as they are produced as a normal byproduct of the electron transport system. Methods: Male albino Wistar rats were used in this study. The animals were divided into 6 groups, each group consisting of 6 animals. Groups I, III, and V were young, middle-aged and aged control rats and Groups II, IV, and VI were treated with carnitine (300 mg/kg bw) and DL-alpha-lipoic, acid (150 mg/kg bw), respectively. After the treatment period, the animals were sacrificed and the heart and skeletal muscle were removed for analysis. Result: There was a significant reduction in the levels of antioxidants in both middle-aged and aged rats whereas the thiobarbituric acid reactive substances were found to be increased. Co-supplementation of carnitine and lipoic acid improved the antioxidant status and brought down the levels of TBARS. Conclusion: Co-supplementation of lipoic acid with carnitine has a beneficial effect in reversing the age-related abnormalities seen in aging. This effect was associated with the decrease in free radical production and rise in antioxidant levels by carnitine and lipoic acid, thereby lowering oxidative stress. (c) 2005 Elsevier B.V All rights reserved.