Sub-chronic exposure to arsenic and dichlorvos on erythrocyte antioxidant defense systems and lipid peroxidation in rats.

The effect of combined exposure to arsenic (25 ppm in drinking water) and dichlorvos (2.5 mg kg1, orally) for 56 days on biochemical variables, indicative of lipid peroxidation, antioxidant enzyme system and AChE activity in erythrocytes of rats, were examined. While arsenic caused a significant increase in AChE, DDVP produced marked depletion. Combined exposure to arsenic and DDVP produced no additional decrease in AChE activity, which was comparable to DDVP. Arsenic and DDVP also increased the levels of reactive oxygen species (ROS) and thiobarbituric acid reactive substances (TBARS), suggesting free radical generation. Interestingly, glutathione linked enzymes (GSH, GPx, GST and GR) significantly increased on arsenic and DDVP exposure. SOD activity also increased significantly in the individually exposed groups, while catalase activity remained unchanged. Blood arsenic level increased significantly on coexposure to arsenic alone and with DDVP exposed group. However, arsenic content in co-exposed group depleted marginally as compared to arsenic alone group, indicating possible arsenic redistribution. It might be concluded from the study that the combined exposure to arsenic and DDVP may lead to synergistic effects on certain biochemical indicators of oxidative stress like ROS, GSH and SOD, suggesting a more pronounced induction of lipid peroxidation in erythrocytes.