Objective To explore the effect of chronic aluminum exposure on learning and memory and the phosphorylation levels of tau protein in mice.
Methods Three groups of mice were fed with AlCl3 at 120.0, 12.0 and 1.2 mg/(kg& #183;d) respectively for 1 year, and one control group with normal diet. Spatial learning and memory ability were tested with Morris water maze (MWM). Brain aluminum content was determined by inductively coupled plasma mass spectrometry (ICP-MS). The expression of total tau and phosphorylated tau in Thr181, Thr231, Ser262 and Ser396 sites in brain tissues of mice were detected by Western blot.
Results Compared with the control group, the MWM latent period of high and middle dose groups was significantly prolonged (P<0.05); the number of traversing platform in high and middle dose groups were significantly decreased (P<0.05); and brain aluminum levels of all 3 exposure groups were significantly higher (P<0.05). Western blot test demonstrated that the total tau and the phosphorylation levels in Thr181, Thr231, Ser262 and Ser396 sites of all 3 exposure groups were significantly higher than those of the control group (P<0.05).
Conclusion Aluminum exposure can lead to cognitive dysfunction in mice and the overphosphorylation of tau protein, which may be one of the mechanisms of cognitive dysfunction induced by aluminum.
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