双氢青蒿素对Raji细胞放射敏感性的影响

目的：研究双氢青蒿素（DHA）对Raji细胞放射敏感性的影响并探讨其作用机制。方法：CCK8测定DHA对Raji细胞活力的影响，流式细胞术检测细胞凋亡、胞内ROS及线粒体膜电位，Western blot检测AKT、p-AKT、Bcl-2、Bax和Cleaved-Caspase-3蛋白表达量。结果：实验分为对照组、DHA组（5 μmol/L DHA）、放射组（4 Gy γ射线）、联合放射组（5 μmol/L DHA和4 Gy γ射线），与其他3组相比，联合放射组Raji细胞的线粒体膜电位显著降低（P<0.01），胞内ROS含量和凋亡率显著升高（P<0.01）；此外，Raji细胞AKT表达量与其他3组相比无明显差异，但AKT的磷酸化受到抑制；Bcl-2表达量显著降低，而Bax、Cleaved-Caspase-3表达量显著升高。结论：DHA可能通过抑制磷酸肌醇3-激酶（PI3K-AKT）信号通路及激活了Raji细胞的线粒体凋亡途径，引起氧化应激反应，从而增加Raji细胞对放射的敏感性。

Effects of dihydroartemisinin on radiosensitivity of Raji cells

Objective: To study the effects of dihydroartemisinin (DHA) on radiation sensitivity of Raji cells, and explore its mechanisms.Methods: CCK8 was used to determine the effect of DHA on cell viability of Raji cells; apoptosis, intracellular reactive oxygen speies(ROS) and mitochondrial membrane potential of Raji cells were detected by flow cytometry; and the protein expressions of protein kinase B(AKT), phospho-rylated-protein kinase B(p-AKT), Bcl-2 and Bax were determined by Western blot.Results: The cells were randomly divided into four groups:control group, DHA(5μmol/L DHA), irradiation(IR, 4 Gy), IR+DHA group (4 Gy IR+5 μmol/L DHA). Compared with the other three groups, cells in DHA+IR group exhibited lower mitochondrial membrane potential (P<0.01). While the intracellular ROS content and apoptosis rate of Raji cells in DHA+IR group were increased significantly(P<0.01). In addition, compared with the other three groups, there was no significant difference in the expression of AKT, but the phosphorylation of AKT protein were significantly inhibited and the expression of Bcl-2 protein was markedly decreased. However, the expressions of Bax and Cleaved-Caspase-3 protein were markedly increased.Conclusion: DHA might activate the mitochondrial apoptotic signal via inhibiting phosphoinositide 3-kinase (PI3K/AKT) pathway and increase oxidative stress to enhance the radiosensitivity of Raji cells.