野黄芩苷对人脑胶质瘤U87细胞的增殖抑制作用及其机制

目的：探讨野黄芩苷（SCU）对人脑胶质瘤U87细胞的增殖抑制作用，并初步阐明其作用机制。方法：培养U87细胞，采用不同浓度（20、40和80 mg·L^-1） SCU处理U87细胞（野黄芩苷组），同时设空白对照组。MTT法检测各组U87细胞存活率，倒置显微镜观察U87细胞的形态表现，Annexin Ⅴ/PI双染检测各组U87细胞凋亡率，Western blotting法检测各组U87细胞中bax和bcl-2蛋白表达水平。结果：MTT法，与空白对照组比较，20、40和80 mg·L^-1SCU组细胞存活率均明显降低（P<0.01）。倒置显微镜观察，与空白对照组比较，80 mg·L^-1SCU组细胞数明显减少，细胞体积变小，细胞间距变大；细胞出现皱缩、脱落，贴壁细胞轮廓模糊。Annexin Ⅴ/PI双染，与空白对照组比较，80 mg·L^-1SCU组细胞晚期凋亡率和总凋亡率均明显升高（P<0.01）。Western blotting法，与空白对照组比较，20、40和80 mg·L^-1 SCU组U87细胞中bcl-2蛋白水平降低，80 mg·L^-1SCU组差异有统计学意义（P<0.01）；与空白对照组比较，80 mg·L^-1 SCU组U87细胞中bax/bcl-2比值升高（P<0.01）。结论：SCU通过上调U87细胞中bax/bcl-2比值诱导细胞凋亡从而抑制肿瘤细胞的生长。

Inhibitory effect of scutellarin on proliferation of human glioma U87 cells and its mechanism

Objective: To explore the inhibitory effect of scutellarin(SCU) on the proliferation of human glioma U87 cells,and to clarify its mechanism. Methods: The U87 cells were cultured and divided into blank control group and 20,40,80 mg·L^-1 SCU groups,the surival rates of U87 cells in various groups were examined by MTT assay; the morphology of U87 cells in various groups were observed by inverted microscope;the apoptotic rates of U87 cells were examined by Annexin Ⅴ/PI staining; the expression levels of bax and bcl-2 proteins in the U87 cells in various groups were detected by Western blotting method. Results: The MTT results showed that compared with blank control group,the survival rates of U87 cells in 20,40,and 80 mg·L^-1 SCU groups were decreased(P<0.01).The inverted microscope observation results showed that compared with blank control group,the number of U87 cells in 80 mg·L^-1 SCU group was significantly decreased,and the cell volume was smaller;the U87 cells were shrinkage,shedding,and the outline of adherent cells was fuzzy.The results of AnnexinⅤ/PI staining showed that the late and total apoptotic rates of U87 cells in 80 mg·L^-1 SCU group were increased compared with blank control group (P<0.01).The Western blotting results showed that compared with blank control group,the expression levels of bcl-2 protein in the U87 cells in 20,40 and 80 mg·L^-1 SCU groups were decreased,especially in 80 mg·L^-1 SCU group(P<0.01).Compared with blank control group,the ratio of bax/bcl-2 in the U87 cells in 80 mg·L^-1 SCU group was significantly increased(P<0.01). Conclusion: SCU can induce the apoptosis and suppress the tumor growth by upregulating the bax/bcl-2 ratio in the U87 cells.