冬凌草甲素诱导人脑胶质瘤U251细胞的凋亡及其机制

目的 研究冬凌草甲素对人脑胶质瘤U251细胞体外生长抑制及诱导凋亡的作用及其机制。方法 MTT法检测冬凌草甲素对U251细胞的生长抑制作用；倒置显微镜法和荧光显微镜Annexin V-FITC/PI双染色法观察细胞的形态学变化；流式细胞仪Annexin V FITC/PI双染色法检测细胞凋亡率；Realtime PCR法检测冬凌草甲素作用U251细胞后的bcl 2、bax及caspase-3基因表达水平的变化。结果 冬凌草甲素对U251细胞有明显的生长抑制作用（P<0.05），呈明显的时间和浓度效应关系。冬凌草甲素作用U251细胞24h后出现明显的细胞凋亡形态学改变。随着冬凌草甲素作用浓度增加，凋亡和坏死细胞数均增加，浓度越高，诱导细胞凋亡的作用越明显（P均 <0.05）。随着冬凌草甲素作用时间延长，U251细胞的bax和caspase-3基因的表达逐渐增强，bcl-2基因的表达逐渐减弱（P均<0.05）。结论 冬凌草甲素能诱导人脑胶质瘤U251细胞凋亡，其凋亡机理可能与bax和caspase 3基因表达的上调，bcl-2基因表达的下调相关。

Effects of oridonin on the progress of apoptosis in human glioma U251 cells and its mechanisms

Objective    To investigate apoptosis-induction effects of oridonin on human glioma U251 cells and its mechanisms in vitro. Methods    MTT method was used to investigate the inhibitory effects of oridonin on U251 cells. Cellular morphologic changes were observed by means of phase contrast microscopy and fluorescence microscopy with Annexin V-FITC/PI staining. Apoptosis-induction effects were evaluated by flow cytometry. Expression of bcl-2, bax and caspase-3 was evaluated by Realtime PCR. Results    Oridonin could inhibit the growth of U251 cells significantly in a time-and dose-dependent manner. Marked morphological changes of cell apoptosis were observed 24h later after the cells were exposed to oridonin. The apoptosis-induction  effects of oridonin were in a dose-dependent manner（P<0.05）. Along with the process of apoptosis，bcl-2 expression was down-regulated and bax,caspase-3 expressions were up-regulated concurrently（P<0.05）.Conclusion    Oridonin can inhibit cell growth by inducing apoptosis in U251 cells via down-regulating the expression of bcl-2 and up-regulating that of bax and caspase-3.