[Protective effects of puerarin against 1-methyl-4-phenylpyridinium-induced mitochondrial apoptotic death in differentiated SH-SY5Y cells].

It is well known that puerarin possesses protective activity on neurodegenerative diseases. However, the exact path way involved in the protective effect of puerarin on MPP+ -induced cell death is unclear. In this study, we focused on mitochondria im pairment in the apoptotic process of MPP+ -elicited SH-SY5Y cells and detected the protection of puerarin. As evidenced by Trypan blue assay, the cell viability was significantly decreased by 1 mmol x L(-1) MPP+, but reversed by different concentrations puerarin pre treatment. Flow cytometer analysis revealed that MPP+ -induced SH-SY5Y cells apoptosis and arrested the cells in G2/M phase, where as puerarin pretreatment concentration dependently reversed the apoptosis ratio. In addition to the apoptosis ratio, 50.0 micromol x L(-1) puerarin pretreatment even altered the MPP+ -induced G2/M phase arrest. JC-1 assay suggested that MPP+ significantly opened MMP of the SH-SYSY cells; pretreatment with puerarin attenuated the deterioration of the MMP. Both ELISA and Western blotting showed that puerarin prevented the release of cytochrome c from the mitochondrial interior to the cystol elicited by MPP+. DNA ladder showed that typical DNA ladder was present in the MPP+ -induced SH-SY5Y cells. Additionally, MPP+ enhanced caspase-9 and caspase-3 ac tivity, respectively, while not caspase-8. However,the enhancement was concentration dependently blocked by puerarin pretreatment. Taken together, puerarin can modulate mitochondrial membrane potential and inhibit the cytochrome c releasing-caspase cascade to pre vent MPP+ -induced cell injury.