Effect of cysteine, methionine, ascorbic acid and thiamine on arsenic-induced oxidative stress and biochemical alterations in rats

Oxidative stress due to enhanced production of free radicals has been incriminated as one of the several mechanisms involved in arsenic-induced toxic effects in different organs. In the present study, ameliorative potential of certain amino acids like cysteine, methionine and vitamins like ascorbic acid and thiamine on some of the parameters indicative of oxidative stress in liver, kidney and blood and of hepatic and renal infliction was investigated in arsenic exposed rats. Rats were given 0 ppm (group I healthy controls) or 10 ppm arsenic in drinking water ad lib for a period of 12 weeks. During oral exposure to arsenic rats of different groups received daily oral dose of placebo, cysteine, methionine, ascorbic acid or thiamine at 25 mg/kg body weight. After the end of the experimental period, animals were sacrificed under light anesthesia and blood, liver and kidney were collected. Samples were processed for estimation of arsenic, biochemical parameters indicative of oxidative stress and hepatic and renal function. Arsenic exposure resulted in significantly (P < 0.05) higher accumulation of arsenic in blood, liver and kidney. It was associated with significant (P < 0.05) rise in lipid peroxide level and decrease in superoxide dismutase and catalase activities in liver and kidneys. However, alterations in biochemical parameters did not reach statistical (P > 0.05) significance. Treatment with vitamins and amino acids resulted in reversal of oxidative stress with significant (P < 0.05) decline in tissue arsenic burden. All the treatment produced tissue specific changes in lipid peroxide level, antioxidant enzyme activities and tissue arsenic burden.