Lead(Pb~(2+)) impairs ability of learning and memory and effects expression of CTGF in hippocampus in mice

Objective To find the effect of lead on learning,memory and the expression of CTGF mRNA and protein in rats for further revealing neurotoxic mechanism of lead.Methods Pregnant mice(10 for ecah group)were exposed to low(0.3 g/L),moderate(1 g/L) and high-level(3 g/L) Pb acetate in deionized drinking water from the first day of gestation to 21th postnatal day(PND).The lead concentration in blood and hippocampus at the 7th,14th,21th day of neonatal mice pups was determined with graphite furnace atomic absorption spectrometry.The ability of learning and memory and the expression of connective tissue growth factor(CTGF) mRNA and protein in hippocampus of different pup groups at the 21th day were measured with Water Morris Maze,RT-PCR and immunohistochemistry assay.Results The lead concentration in lead exposure group was higher than that of control group(P0.05).The change of the lead level in blood and hippocampus showed a regular pattern.In Water Morris Maze test,the mean incubation period in control group,low,moderate,high lead exposure group were 39.13±6.12,43.22±9.86,50.85±12.35,50.85±12.35 seconds,respectively.The relative expression level of CTGF mRNA in control group,low,moderate,and high lead exposure group were 0.354±0.603,0.945±0.522,1.223±0.279,1.612±0.136,and the gray scale of CTGF in hippocampus of pups were 126.10±32.11,186.31±36.17,220.94±31.27,286.21±31.24,respectively.The low lead exposure group showed no statistically significance compared with the control group(P0.05).However,there were statistical differences in moderate and high lead exposure groups(P0.05,P0.01).The expression of CTGF mRNA and protein was stronger in lead exposure groups than in control group(P0.05).Conclusion Pb acetate exposure in pregnant mice results in lead accumulation in the body of rat pup,and affects study and memory function of pup mice.The neurotoxicity of Pb may result from the lead-induced high expression of CTGF mRNA and protein.