The cell death of C6 astrocytoma cells induced by oridonin and its mechanism.

Many studies have shown that oridonin, a compound purified from Rabdosia rubescens, was able to suppress proliferation and induce apoptosis in many cell types. In this study, In order to investigate the proliferation suppression and apoptosis-inducing effect of oridonin on Rat C6 astrocytoma cells, we treated C6 cells with different concentrations of oridonin for various time intervals. Oridonin concentration-time viability curve were used to test the effect of oridonin on the C6 cells. The distribution of cell cycle and percentage of apoptosis cells was analyzed by flow cytometry. The protein expression of Bax, Bcl-2, and caspase-3 in the C6 cells was detected by western blot analysis. The results of viability curve demonstrated that oridonin induced suppression of proliferation in a concentration- and time-dependent manner. Hochest 33258 staining and flow cytometry revealed that oridonin induced apoptosis and arrested the entry into G2/M phase of C6 cells. According to the results of Western blot, oridonin down-regulated Bcl-2, up-regulated Bax protein, and activated caspase-3 in the oridonin-treated C6 cells. All together, our results suggested that oridonin can cause the suppression of proliferation in C6 astrocytoma cells and the cell death induced by oridonin might be associated with mitochondria- mediated apoptosis by activating caspase-3.