OBJECTIVETo observe the effect of chronic lead contaminant on mRNA expression of protein kinase C (PKC) and calmodulin (CaM) in hippocampus of baby rats.

METHODSThe Wistar pregnant rats were randomly divided into 3 groups fed with distilled water and lead contained water (0.2% and 1.0% lead acetate) respectively. The lead exposure period was from the 0 day of pregnancy to the day when the offspring weaned. Then the baby rats were fed with lead water the same as their mothers. The cliff avoidance reflex within postnatal day 8 and step down test at postnatal day 50 were performed. Then pups were killed at postnatal day 8 and 50 respectively. Atomic absorption spectrometry was used to determine lead content of rats' brain. RT-PCR was used to observe mRNA expression of PKC and CaM in hippocampus of baby rats.

RESULTSThe brain lead content of test groups were much higher than that of the control group. The completion rate of cliff avoidance reflex and the score of step down test of test groups were lower than those in the control group (P < 0.05). Compared with control group, PKC and CaM mRNA expression of chronic lead exposure baby rats in the hippocampus had the down trend (P < 0.05).

CONCLUSIONThe decrease of PKC and CaM mRNA expression level in hippocampus has a great link with the impairment of learning and memory induced by lead in baby rats, which might be one of the molecule mechanisms of lead induced impairment of learning and memory.