Objective To investigate lead-induced changes of synaptic structure in
hippocampal CA_1 area,and the antagonistic effects
of zinc.Methods Wistar rats were exposed to lead or lead-zine crom dirinking 6.15 mmol/L lead acetate solution or the solution containing 3.10 mmol/L zinc sulphate respectively,for 40 days.Serum and
hippocampal lead content in rats were measured with atomic absorption method;The changes of
subcellular structure of hippocampal CA_1 area were studied with transmission electron microscope and morphometry method.Results Compared with the control and lead-zinc group,the serum and hippocampal lead content of lead-exposed rat was significantly increased (P<0.05);the number of the rough endoplasmic reticulum and mitochondria were decreased,there were a lot of vacuoles in them; the synaptic ratio of synapse containing over 50 vesiculae was decreased (P<0.01),while the constituent ratio of synapse containing less the 10 vesiculae was increased (P<0.01);the membrane area of the presynapses and postsynapses were significantly decreased (P<0.01),but no significant changes were found between the cntrol and lead-zinc groups.Conclusion The effects of lead on the changes of subcellular structure in hippcompal CA_1 area,zinc might play an important role in preventing lead-induced damages.