Effects of Lead on the Learning and Memory Ability and Expression of TGF-β1 in Hippocampus of Mice Offspring

Objective To find the effects of lead exposure during mice pregnancy on the learning and memory ability and the expression of TGF-β1 mRNA and protein in hippocampus of their offspring,and to provide scientific criteria for further revealing neurotoxicity mechanism of lead.Methods Lead exposure was conducted through freely drinking the corresponding lead acetate solutions with dosages of 0.3,1 and 3g/L respectively.Each group composed of 10 mice.7,14 and 21 days after their birth,the lead contents in blood and hippocampus of the offspring were determined.At postnatal 21st day the expression of TGF-β1 mRNA and protein in hippocampus of all the offspring in various dosages groups were determined by RT-PCR and immunohistochemistry assay.Results The lead contents in blood and hippocampus of various lead exposed groups were significantly higher than those of the control group (P0.05).The lead levels in blood and hippocampus changed accordingly to the days of growth.In Water Morris Maze experiment,the result of low dosage group was not significantly different from that of the control group(P0.05),however,the results of medium and high dosages groups were significantly different from those of the control group(P0.05,P0.01).The expression of TGF-β1 mRNA and protein was stronger in lead exposed groups than that of the control group(P0.05).Conclusions Maternal lead exposure may induce the accumulation of lead in the offspring,in turn inducing the damage in the ability of learning and memory of the offspring.The neurotoxicity of lead may be induced by the expression of TGF-β1 mRNA and protein so as to change the conduction paths of some signals resulted in nerve damages.