目的　探讨维生素C是否可增强三氧化二砷 (As2 O3 )联用二甲萘醌 (DMNQ)对白血病细胞株U937的促凋亡效应及其机制。方法　以As2 O3 、维生素C、DMNQ不同组合孵育细胞 ,采用流式细胞仪及电镜检测细胞凋亡 ,并设立各种对照。结果　维生素C可增加As2 O3 联用DMNQ(10 μmol/L)诱导U937细胞发生凋亡的比例 (不加和加用维生素C细胞凋亡率分别为 35 .2 4%和 6 1.2 0 % ) ;过氧化氢酶可逆转这一效应 ;维生素C对DMNQ(2 0 μmol/L)单独诱导U937细胞凋亡无影响。 结论　维生素C在As2 O3 存在的情况下 ,通过活性氧依赖的途径 ,促进U937细胞凋亡 Objective To investigate whether vitamin C can enhance the pro-apoptotic effect of As2O3 and meconazole (DMNQ) on leukemia cell line U937 and its mechanism. Methods The cells were incubated with different combinations of As 2 O 3, vitamin C and DMNQ. Apoptosis was detected by flow cytometry and electron microscopy, and various controls were set up. Results Vitamin C increased the apoptosis rate of U937 cells induced by As2 O3 combined with DMNQ (10 μmol / L) (35.24% and 62.2% respectively). Catalase could reverse this effect; Vitamin C had no effect on the apoptosis of U937 cells induced by DMNQ alone (20 μmol / L). Conclusion Vitamin C promotes the apoptosis of U937 cells in the presence of As2 O3 through a ROS-dependent pathway