Effect of lead on erythrocytic antioxidant defence, lipid peroxide level and thiol groups in calves

Fifteen crossbred male calves were exposed to lead fur a period of 25 days orally at the dose rate of 7.5 mg of lead acetate as 0.75 per cent solution kg(-1) body weight to study its effect on erythrocytic antioxidant defense , lipid peroxide level and thiol groups. Five calves were given no treatmen t and served as unexposed controls. Blood samples were collected before exp osure to lead and thereafter at weekly intervals tie. on day 7, 14, 21 and 28). Erythrocyte haemolysate (10 per cent) was prepared and analysed for li pid peroxide level, activity of Superoxide dismutase (SOD) and catalase. To tal, protein-bound and non protein-bound thiol groups were also measured. E xposure to lead significantly (P < 0.05) reduced the erythrocytic SOD activ ity by day 7 and it remained lower until day 21 followed by a marginal incr ease on day 28. Catalase activity declined after an initial compensatory ri se on day 7. Erythrocytic Lipid peroxide level was recorded to be significa ntly (P < 0.05) higher by day 21 and 28 of exposure. Total, protein-bound a nd non protein bound -SH content of erythrocytes declined. It was concluded that oral exposure of lead reduced the erythrocytic thiol content and anti oxidant defence indicating possible role of free radicals in pathogenesis o f lead toxicity. (C) 2000 Harcourt Publishers Limited.