RÉSUMÉ
Objective To observe the effect of Puerarin on the level of tau phosphorylation in the olfactory bulb of Alzheimer's disease rat brain, and explore the underlying molecular mechanism.Methods ① Twenty-two male SD rats were randomly divided into the normal control group, model control group and Puerain-treated group.The levels of tau-1, PS396 and tau-5 in the olfactory bulb were detected by Western blotting.② Twenty male SD rats were randomly divided into model control group, low-dose Puerarin (40 mg·kg-1·d-1), medium-dose puerarin (80 mg·kg-1·d-1) and high-dose puerarin (160 mg·kg-1·d-1) groups.The levels of tau-1 and PS396 phosphorylation in the olfactory bulb were detected by Western blotting.③ The level of GSK-3β phosphorylation in the olfactory bulb of the normal control group, model control group A and puerain-treated group was detected by Western blotting.Results ① It was shown by Western blotting that the relative expression of tau-1 was significantly decreased in the olfactory bulb of the model group A(0.49±0.07)rat brain compared with the normal control group(0.85±0.03)(P<0.01), and the level of tau-1 was obviously higher in the puerarin-treated group(0.58±0.03)compared with that of the model group A(P<0.05).The differences of the levels of tau-5 and PS396 in the olfactory bulb were insignificant among the 3 groups.②Compared with the model group B, the expression of tau-1 in the olfactory bulb was significantly enhanced in the low-, medium-and high-dose of puerarin group: (0.39±0.09)vs(0.69±0.11),(0.55±0.11),(0.70±0.04);and the level of PS396 was significantly decreased in the olfactory bulb of low-dose puerarin group(0.36±0.07) compared with the model group B(0.55±0.05)(P<0.01).③Compared with the normal control group(0.96±0.07), the ratio of pS9-GSK-3β/tGSK-3β was obviously decreased in the olfactory bulb of the model group A(0.51±0.12),while that was significantly increased in the puerarin group(0.62±0.03) compared with the model group A(P<0.01).Conclusion Puerarin can attenuate AD-like tau hyperphosphorylation in the olfactory bulb of Alzheimer's disease rat brains, and decreased activity of GSK-3β might be involved in the effects of puerarin on tau hyperphosphorylation.