黄芪总黄酮对辐射肝癌细胞的促凋亡作用

目的从细胞和蛋白水平研究黄芪总黄酮（total flavonoids of astragalus，TFA）对辐射肝癌细胞的促凋亡作用。方法以对数生长期的HepG－2肝癌细胞为实验对象，克隆形成实验检测细胞的辐射敏感性；流式细胞技术分析细胞凋亡率；Westernblot技术分析凋亡相关蛋白Fas、Bcl－2、Bax的表达。结果细胞克隆形成实验结果显示，TFA给药照射组能够明显抑制HepG－2细胞增殖，作用强于单纯TFA给药组和单纯照射组。流式分析结果也提示，经6Gv1射线一次性照射6、24h和48h后，TFA预处理组肝癌细胞HepG－2的细胞凋亡率分别为（11．6±2．2）％、（17．3±1．5）％和（20．1±2．8）％，单纯照射组HepG－2的细胞凋亡率分别为（6．±2．3）％、（9.3±3．5）％和（15．8±2．1）％。Westernblot分析结果提示，在肝癌细胞HepG－2中，TFA预处理照射组促凋亡蛋白Fas和Bax的表达量显著高于单纯照射组和对照组；凋亡抑制蛋白Bcl－2的表达量正好与此相反，TFA预处理照射组Bcl－2的表达量明显低于单纯照射组和对照组。结论TFA对肝癌细胞不仅没有辐射保护作用，而且能够增强辐射对肝癌细胞的毒性作用。

Effects of total flavonoids of astragalus on promotive apoptosis of radiated hepatoma cells

Objective To explore the pro-apoptotic effects of total flavonoids of astagalus(TFA) on radiated hepatoma cells in the cell and protein levels.Methods With the growing period of logarithm HepG-2 liver cancer cells for experimental object,the cell clone formation test was used to measure the cellular radiosensitivity;the apoptosis rates of different groups were determined by flow cytometer assay;the expression of apoptosis related gene such as Fas,Bcl-2 and Bax were detected by western blotting.Results The cell clone formation rate showed that the combined treatment group with TFA and radiation had greater inhibition on cell proliferation of HepG-2 than the group of TFA pretreatment or γ-ray treatment only.The data from flow cytometry showed that the apoptosis rates of HepG-2 at 6,24 h and 48 h post-irradiation by 6 Gy γ-ray were respectively(11.6±2.2)%,(17.3±1.5)% and(20.1±2.8)% in the TFA pretreatment group and were(6.9±2.3)%,(9.3±3.5)%,and(15.8±2.1)% respectively in the direct radiation group.Western blot analysis displayed that the expressions of apoptosis promoting proteins such as Fas and Bax in the hepatoma cell HepG-2 were significantly higher in the TFA pretreatment group than that in the direct radiation group.On the other hand,the expressions of apoptosis inhibiting protein such as Bcl-2 was significantly lower in the TFA pretreatment group than that in the direct radiation group or control group respectively.Conclusion TFA has not the radiation protection but can enhance the radiation toxicity on the hepatoma cell.