Treatment with vitamin C and metal chelators reverses lead-induced DNA damage in liver and brain tissues of albino rats

Lead toxicity resulting from occupational or environmental exposure has long been treated with chelating agents and/or antioxidants. The ameliorative effects of these chelators on the genotoxicity of lead and possible damage on the DNA are yet to be fully investigated. In this study, the efficacy of conventional chelators (namely; 2, 3-mesodimecarptosuccinic acid (DMSA), D-Penicillamine and Calcium disodium ethylene di amine tetra acetate (CaNa 2 EDTA) with vitamin C were compared in the tissues of experimental rats exposed to lead. Twenty four hours after the last treatment, animals were sacrificed under anaesthesia, the brain and the liver of the animals were then harvested, mopped dry and stored on ice. Quantitative DNA fragmentation was determined spectrophotometrically using the diphenylamine reaction. Result showed a 4-fold increase in the percentage damage observed in the brain of animals administered lead for 12 weeks, with a 2-fold increase observed in the liver over the control group. Treatment with Vitamin c and CaNa 2 EDTA for 5 days and 10 days significantly reduced the fragmentation percentage in the liver. While CaNa 2 EDTA seem to have no significant ameliorative effect in the brain tissue. Treatment with D-Penicillamine also showed significant ameliorative effect in both tissues. Ten days treatment with succimer however proved more effective than the 5 days treatment. The results of this experiment did suggest a gradual reversal in oxidative DNA damage following withdrawal from exposure and the most effective treatment observed with vitamin c in both tissues.