The aim of this study was to investigate the protective effect of vitamin C towards hyperhomocysteinemia (hHcy) induced oxidative DNA damage using the comet assay. The increase in plasma homocysteine levels is an important risk factor for vascular and cardiovascular diseases through free radical production. This study was also conducted to investigate the histopathological changes in the thoracic aorta and the oxidant/antioxidant status in heart, liver and kidney tissues. Twenty-four adult male Wistar rats were divided as control, hHcy and hHcy+vitamin C group. Chronic hHcy was induced by oral administration of l-methionine (1g/kg/day) for 28 days. Vitamin C was given 150mg/kg/day within the specified days. DNA damage was measured by use of the comet assay in lymphocytes. Levels of malondialdehyde (MDA) and glutathione (GSH) as well as catalase (CAT) and superoxide dismutase (SOD) activities were determined in heart, liver and renal tissues. Results show that l-methionine administration significantly increased % Tail DNA and Mean Tail Moment in hHcy group as compared with other groups. Vitamin C treatment significantly decreased the high MDA levels and increased activity of antioxidant enzymes in tissues. Aortic diameter and thickness of aortic elastic laminae were significantly lower in hHcy+vitamin C group. Comet assay can be used for the assessment of primary DNA damage caused by hHcy. Histopathological findings showed that vitamin C may have a preventive effect in alleviating the negative effects of hHcy. Vitamin C might be useful in the prevention of endothelial dysfunction caused by hHcy.
Keywords: Comet assay; Hyperhomocysteinemia; Lymphocyt; Oxidative stress; Rats; Vitamin C.
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