[Ginsenoside Rbl attenuates beta-amyloid peptide25-35 -induced tau hyperphosphorylation in cortical neurons].

Aim: To explore the effect and the possible mechanism of ginsenoside Rb1 on beta-amyloid peptide (beta-AP)(25-35) -induced tau protein hyperphosphorylation in cortical neurons.

Methods: Western blotting and immunocytochemical staining were used to detect tau phosphorylation level, total tau and glycogen synthase kinase-3beta (GSK-3beta) in cortical neurons.

Results: After exposure to beta-AP(25-35) (20 micromol x L(-1)) for 12 h, the levels of tau protein phosphorylation in the sites of Ser 396, Ser 199/202, Thr 231 and total tau were raised. Meanwhile, the expression of GSK-3beta also increased. Pretreatment with ginsenoside Rbl or lithium chloride, a specific inhibitor of GSK-3beta, markedly reduced beta-AP(25-35)-induced tau hyperphosphorylation and the expression of GSK-3beta.

Conclusion: Ginsenoside Rb1 can attenuate beta AP(25-35)-induced tau protein hyperphosphorylation in cortical neurons by inhibiting the expression of GSK-3beta.