目的　研究半胱天冬酶 3在国产氨肽酶N抑制剂Bestatin(商品名百士欣 ,BS)诱导人白血病细胞凋亡过程中的变化及其意义。方法　用光学显微镜观察细胞形态结构的改变 ,通过DNA片段原位末端标记法及流式细胞术 (FCM)检测细胞凋亡。用发色底物法检测细胞半胱天冬酶 3活性。Rhodamin(Rh) 12 3染色后 ,采用FCM检测细胞线粒体跨膜电位。结果　典型的细胞形态改变、DNA片段化、DNA末端原位标记及FCM结果 ,均证实BS能诱导HL 6 0细胞凋亡。凋亡率与药物剂量和作用时间呈依赖关系。BS诱导细胞凋亡过程中 ,半胱天冬酶 3活性明显升高 ,而AC DEVD CHO能抑制BS诱导的细胞凋亡。经BS处理的HL 6 0细胞出现线粒体跨膜电位 (ΔΨm)下降。结论　BS通过激活半胱天冬酶 3而诱导白血病细胞凋亡。 Objective To study the changes and significance of caspase 3 in the apoptosis of human leukemia cells induced by the bestatin of aminopeptidase N (BSS). Methods The morphological changes of cells were observed with optical microscope. Apoptosis was detected by DNA in situ end labeling and flow cytometry (FCM). The activity of cell caspase 3 was assayed by chromogenic substrate method. Rhodamin (Rh) 12 3 staining, cell mitochondrial transmembrane potential was detected by FCM. Results Typical cell morphological changes, DNA fragmentation, DNA terminal in situ labeling and FCM results all confirmed that BS could induce HL-60 cell apoptosis. The rate of apoptosis is dependent on the dose and duration of action. During the induction of apoptosis by BS, caspase 3 activity was significantly increased, while AC DEVD CHO inhibited BS-induced apoptosis. The mitochondrial transmembrane potential (ΔΨm) decreased in BS-treated HL 60 cells. Conclusion BS induces apoptosis of leukemic cells by activating caspase-3.