铅对仔鼠海马蛋白激酶C和钙调蛋白表达的影响

目的 研究慢性铅染毒对不同发育时期仔鼠海马蛋白激酶C(PKC)、钙调蛋白(CaM)表达的影响.方法 孕鼠随机分为蒸馏水对照组、0.2%醋酸铅和1.0%醋酸铅组,从怀孕第0灭起开始通过自由饮水染毒.幼鼠出生后,先通过哺乳接触铅,断乳后则自行饮用与其母鼠浓度相同的含铅水.分别于出生后8、50 d处死仔鼠,原子吸收光谱法测定脑铅含量,Western-blotting法观察各组仔鼠海马PKC、CaM的蛋白表达情况.结果 同一发育时期的染铅组仔鼠脑铅含量明显高于对照组,差异有统计学意义(P＜0.01).同一剂量染铅组出生后50 d仔鼠脑铅含最明显高于出生后8 d,差异有统计学意义(P＜0.01).不同发育时期的染铅组仔鼠海马的PKC、CaM的蛋白表达均相应地下降,与对照组相比,差异有统计学意义(P＜0.05).结论 仔鼠海马PKC、CaM的蛋白表达降低可能是铅致仔鼠学习记忆功能损害的分子机制之一.

Effects of lead exposure on protein kinase C and caimodulin expression in hippocampus of baby-rats

ObJective To observe the effect of chronic lead contaminant on protein expression of protein kinase (PKC) and calmodulin (CAM) in hippocampus of baby-rats.Methods The Wistar preg-nant rats were randomly divided into 3 groups fed with distilled water and lead-contained water (0.2% and 1.0% lead actate) respectively.The lead exposure period ranged from the 0 day of pregnancy to the offspring weaned.Then the baby-rats were fed with lead water the same as their mothers.Pups were killed at postnatal day 8 and 50 respectively.Atomic absorption spectrometry was used to determine lead content of rats' brain.Western-blotting was used to observe protein expression of PKC and CaM in hippocampus of baby-rats.Results The brain lead content of test groups was much higher than that of the control group in the same growth period (P＜0.01).The content of brain lead in rats of postnatal day 50 was significantly higher than that of rats of postnatal day 8 (P＜0.01).Compared with control group,PKC and CaM protein expressions of chronic lead exposure baby-rats in the hippocampus were downtrend (P＜0.05).Conclusion The decrease of PKC and CaM protein expression level in hippocampus might be one of the molecular mechanisms of lead induced impairment of learning and memory.