Prostate apoptosis response-4 involved in the protective effect of salvianolic acid B against amyloid beta peptide-induced damage in PC12 cells.

To observe the effect of salvianolic acid-B (SalB) against the cytoxicity of amyloid beta peptide (A-beta)(25-35) to PC12 cells, the cells were incubated with A-beta, and the cytoxicity was investigated by MTT, flow cytometry and a cell free apoptotic system. The expression of prostate apoptotic response-4 (Par-4) was detected by Western blot. Aged A-beta 10 micromol/L significantly inhibited the MTT reduction of PC12 cells, SalB1 micromol/L inhibited the toxicity induced by A-beta. In flow cytometric analysis, PC12 cells treated with A-beta exhibited degraded DNA content characteristic of apoptosis cells (1.53% vs 19.9%). PC12 cells pretreated with SalB (10 nmol/L, 100 nmol/L, 1 micromol/L) manifested relatively low proportion of apoptosis (15.7%, 13.5%, 11.8%, respectively). SalB (10 nmol/L - 1 micromol/L) when added at the beginning of the cell free apoptotic reaction had no apparent effect on the nuclei apoptosis. Pretreatment of PC12 cells with SalB largely prevented the increase in Par-4 expression of the cells when they were exposed to A-beta. The results suggest that Par-4 is involved in the protective effect of SalB against A-beta-induced damage in PC12 cells.