铝对大鼠海马ERK蛋白及mRNA表达影响
Effect of chronic aluminium exposure on protein and mRNA expression of ERKs in hippocampus of rats
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摘要:目的 研究慢性铝中毒对大鼠海马细胞外信号调节蛋白激酶(ERK)蛋白及mRNA表达水平的变化, 探讨铝中毒对学习记忆机制的影响。方法 选择断乳后Wistar大鼠, 用不同浓度AlCl3的水饲养3个月。测量大鼠海马长时程增强(LTP), 用改良的Takai法测定丝裂原活化蛋白激酶(MAPK)活性的变化, 蛋白印迹(Western blotting)方法检测ERK1/2的蛋白含量, RT-PCR方法检测ERK2的mRNA表达。结果 (1) 各染铝组MAPK活性降低且与对照组比较差异有统计学意义(P < 0.05);(2)ERK1/2蛋白表达的比较: ①ERK2在大鼠海马中的蛋白含量高于ERK1;②染铝组ERK1/2非磷酸水平与对照组比较均有所下降(P < 0.05), 但染铝组之间差异无统计学意义(P > 0.05);③染铝组ERK1/2磷酸化水平与对照组的比较均有下降(P < 0.05), 染铝组之间的差异有统计学意义(P < 0.05)。(3)染铝组ERK2的mRNA表达与对照组比较明显降低, 但染铝组之间差异无统计学意义(P > 0.05)。结论 慢性铝中毒不仅影响大鼠海马中ERK2的mRNA表达水平, 同时也影响ERK1/2的蛋白表达水平的降低, 造成有丝分裂原活化蛋白激酶(MAPK)活性的下降, 损害LTP的形成, 从而影响学习记忆功能下降。Abstract:Objective To study the changes of Extracellular Signal Regulated Kinase(ERK)content and its mRNA expression level that caused by chronic-aluminium exposure, which can alter the amplitude value of long-term potentiation (LTP), to go deep into the mechanism of learning and memory.Methods The ablactated Wistar rats were used to establish the chronic-aluminium exposed models by the gavage of AlCl3 of different concentrations in the drinking water and LTP in hippocampus of rats was measured.The mitogen-activiated protein kinase(MAPK)activity was determined by modified Takai Method.ERK1/2 content of hippocampus and the mRNA expression level of ERK2 were determined by Western Blot and RT-PCR methods individually.Results (1) The MAPK activity of AlCl3 exposed groups was obviously lower than that of control groups(P < 0.05).(2)The content of ER K1/2 in the hippocampus of AlCl3-exposed groups fell down comparing with that of control groups but there was no statistic difference between the AlCl3-exposed groups(P > 0.05).(3)The amount of ERK2 was higher than that of ERK1 in the nervous system and the expression of ERK2 protein of aluminium exposed groups showed a downwards tendency comparing with that of control groups(P < 0.05).(4)ER K1/2 phosphorylation level of aluminium exposed groups obviously decreased comparing with that of control group(P < 0.05).(5)The mRNA expression of ERK2 of AlCl3-exposed groups fell down comparing with that of control groups but there was no statistic difference between the AlCl3-exposed groups(P > 0.05).Conclusion Chronic aluminum exposure can affect not only the mRNA expression of ERK2 but also the expression of ERK1/2 protein and its phosphorylation level, in hence, can reduce the activity of MAPK, damaging the formation of LTP and consequently impairing the ability of learning and memory.
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