Effect of chronic aluminium exposure on protein and mRNA expression of ERKs in hippocampus of rats

  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.