Lipid peroxide level and antioxidant defense in experimental lead neurotoxicity in rats

An experiment was carried out with 48 IVRI 2CQ rats to study the post- expo sure effects of lead on the selected parameters indicative of oxidative dam age, and on the thiol contents in the brain. Rats (24) were given a daily d ose Ca I mg lead/ 2 ml of distilled water/ kg body weight for 30 day throug h an intraperitoneal route. Rats (24) receiving sterile normal saline solut ion served as negative controls. The intraperitoneal injections were withdr awn and 6 rats from each group were sacrificed at the end of the exposure ( day 0) and thereafter on days 3, 7 and 10. The activities of antioxidant en zymes, such as superoxide dismutase and catalase, the levels of lipid perox ides and thiol groups were estimated in brain homogenate. Many fold rise in brain lead concentration at the end of the lead exposure rats was associat ed with increase in the lipid peroxides (LPO) level by 24.5% and catalase a ctivity by 67%, as compared to that of control value, A significantly (P < 0.05) higher lipid peroxides level was recorded on days 3 and 10 and the ac tivity of catalase was on day 3 of withdrawal of lead. A significant decrea se in the protein bound thiol groups (P-SH) and increase in non- protein bo und thiol groups (NP-SH) in the brain was observed at the end of the lead-e xposure. It is concluded that a withdrawal period of 10 days was not suffic ient to reduce the brain lead concentration to normal and subchronic exposu re to lead increased NP-SH and LPO level, suggesting lead-related oxidative stress in brain.