Effect of Lead Exposure on Gene Expressions of Neuron Nitric Oxide Synthase in Hippocampus of Rat

Objective To investigate the effect of lead on the protein and gene expressions of neuron nitric oxide synthase(nNOS)in hippocampus of rat.Methods 12 Wistar rats were exposed to lead by drinking 0 2% lead acetate solution for three months.Study the changes of nNOS positive neuronal numbers and mRNA content in nNOS in hippocampus of rat by immunohistochemical and semi quantitative reverse transcription polymerase chain reaction(RT PCR) method.Results Compared with the control group,the number of nNOS positive neurons in CA 1 area and dentate gyrus of lead exposed rats(46 67±9 04 and 30 53±7 08 respectively)were significantly decreased than the control rats(60 67±13 48 and 57 07±11 14,P0 05 respectively); the numbers of nNOS positive neurons in CA 3 area of lead exposed rats showed no obvious difference with those of control rats.In comparison with control group(0 454±0 045), the nNOS mRNA content of hippocampus(0 071±0 025)decreased notably(P0 01).Conclusions These results suggest that the expression reduction of nNOS positive neuron in hippocampus might be related to the effect of lead on learning and memory.