Antioxidant Role of α-lipoic Acid in Lead Toxicity
The assumption of oxidative stress as a mechanism in lead toxicity suggests that antioxidants might play a role in the treatment of lead poisoning. The present study was designed to investigate the efficacy of lipoic acid (LA) in rebalancing the increased prooxidant/antioxidant ratio in lead-exposed Chinese hamster ovary (CHO) cells and Fischer 344 rats. Furthermore, LA's ability to decrease lead levels in the blood and tissues of lead-treated rats was examined. LA administration resulted in a significant improvement in the thiol capacity of cells via increasing glutathione levels and reducing malondialdehyde levels in the lead-exposed cells and animals, indicating a strong antioxidant shift on lead-induced oxidative stress. Furthermore, administration of LA after lead treatment significantly decreased catalase and red blood cell glucose-6-phosphate dehydrogenase activity. In vitro administration of LA to cultures of CHO cells significantly increased cell survival, that was inhibited by lead treatment in a concentration-dependent manner. Administration of LA was not effective in decreasing blood or tissue lead levels compared to a well-known chelator, succimer, that was able to reduce them to control levels. Hence, LA seems to be a good candidate for therapeutic intervention of lead poisoning, in combination with a chelator, rather than as a sole agent.
H. Özgünes et al., "Antioxidant Role of α-lipoic Acid in Lead Toxicity," Free Radical Biology and Medicine, vol. 27, no. 1 - 2, pp. 75-81, Elsevier, Jul 1999.
The definitive version is available at http://dx.doi.org/10.1016/S0891-5849(99)00036-2
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