Objective To explore the effect of chronic aluminum exposure on cognitive ability and expression of β-APP gene in mice.
Methods The high, middle and low dose groups were established by the gavages which the dosage of AlCl3 in the fodder were 120, 12 and 1.2 mg/kg respectively. The control group was foddered regularly. Three months later, the spatial learning and memory ability were evaluated by step through test(STT), step down test(SDT), and morris water maze(MWM), while gene expression of β-APP by RT-PCR(reverse transcription-polymerase chain reaction).
Results Compared with the control group, the latent period of SDT of high and middle dose groups was significantly decreased(P < 0.05), the error number of SDT of high and middle dose groups was significantly increased(P < 0.05).The latent period of STT of high dose group was significantly decreased(P < 0.05)and the error number significantly increased(P < 0.05). In MWM the latent periods of different dose groups were significantly and constantly extended corresponding with doses of AlCl3(P < 0.05), numbers of traversing flat in high and middle dose groups were significantly decreased(P < 0.05). The expressions of β-APP gene in high and middle dose groups were significantly enhanced compared with the control group. There were dose-response relationships between aluminum exposure and the latent period of SDT(r=-0.725, P < 0.05), of STT(r=-0.765, P < 0.01), and of MWM(r=0.097, P < 0.05). There were dose-response relationships between aluminum exposure and the error number of SDT(r=0.565, P < 0.01), and of STT(r=0.509, P < 0.05). Statistical analysis showed that positive correlations existed between aluminum exposure and expression of β-APP mRNA(rs=0.743, P < 0.05).
Conclusion The exposure to aluminum could result in the dysfunction of the ability of spatial learning and memory of mice and the over-expression of β-APP gene. It might be one of the most important pathogenic mechanisms.
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