Saikosaponin D Inhibiting Phosphorylation Level of Tau Protein in PC12 Cells Challenged to AΒ_(25-35)

Objective: To explore the effect of Saikosaponin D( SSD) on the expression and phosphorylation levels of tau protein in the PC12 cells and the related mechanisms. Methods: The PC12 cells were divided into 3 groups: control group,Aβ group and SSD group. The control group was cultured with conventional culture medium DMEM. Aβ group wascultured with DMEM containing 10 μmol / L Aβ25- 35 and SSD group cultured with DMEM culture medium containing 4μg / m L SSD + 10 μmol /L Aβ25- 35. After 24 hours in culture,cells in each group were collected. RT real- time PCR and Western blot methods were used to detect mRNA expression and protein phosphorylation level changes of tau protein in PC12 cells of each group. Results: For mRNA expression of each group,there was no significant changes( P 0. 05).Compared with control group,phosphorylation levels of tau protein in Aβ group were significantly increased( P 0. 05)while the phosphorylation level was decreased when the cells was treated with SSD. Conclusion: In PC12 cells,SSD may inhibit tau over- phosphorylation initiated by the treatment of Aβ25- 35.