Effects of Lead on Learning and Memory Ability and Expression of TNF-α in Hippocampus of Mice Offspring

Objective To study the poisoning effects of lead exposure during mice pregnancy on learning and memory,the changes of tumor necrosis factor-α(TNF-α) in hippocampus of their offspring,and to find the relationship between TNF-α and neurological impairment.Methods Lead exposure was conducted through freely drinking the corresponding lead acetate solutions with dosages of 0.3,1 and 3 g/L respectively.Each group composed of 10 mice.Lead contents in blood and hippocampus of the offspring were determined 7,14 and 21 days after their birth.At postnatal 21st day the learning and memory ability and expression of TNF-α mRNA in hippocampus of all the offspring in various dosages groups were determined by Morris water maze experiment and RT-PCR.Results The difference in offspring's lead levels of blood and hippocampus were significant(P0.05).In water maze experiment,the escape latency was longer in lead-exposed groups,the longer and higher dosage exposure,the poorer learning performance(P0.05).The expression of TNF-α mRNA in the hippocampus of offspring raised higher in lead exposed groups than that of the control group(P0.01).The expression of TNF-α mRNA in offspring's hippocampus was positively correlated with the lead level of blood and hippocampus and the escape latency on the 21st day(P0.01).Conclusions The perinatal lead exposure may increase the lead level in blood and hippocampus,in turn induce the damage in the ability of learning and memory.The expression of TNF-α in hippocampus of offspring is likely to be correlated with the neurotoxicity of lead.