LIPOPEROXIDATIVE DAMAGE ON LEAD-EXPOSURE IN RAT-BRAIN AND ITS IMPLICATIONS ON MEMBRANE-BOUND ENZYMES

We have investigated the effect of lead exposure on lipid peroxidation , a deteriorative process of the membranes, in the different regions o f the brain. Lead treatment (50 mg/kg b.wt. intragastrically) for a pe riod of eight weeks to rats resulted in a significant accumulation of lead in all the regions of brain, at maximum in hippocampus. The lipid peroxidation was accentuated following lead exposure and there was a linear correlation between the increase in lipid peroxidation and incr ease in lead levels (r = 0.75). The antioxidant capacity of the neuron al cells in terms of the activity of antioxidant enzymes superoxide di smutase, catalase and glutathione peroxidase was diminished. Lead trea tment also altered the glutathione status i.e. levels of reduced gluta thione were lowered, accompanied with the accumulation of oxidized glu tathione. Furthermore, the activity of glutathione reductase was signi ficantly lowered in lead-treated animals. The activity of membrane bou nd enzyme acetylcholinesterase was significantly inhibited following l ead exposure and there was a linear correlation between the increase i n lipid peroxidation and decrease in acetylcholinesterase activity (r = -0.83). It appears from the results that lead may exert its neurotox ic effects via peroxidative damage to the mebranes.