本文研究了硒酸软骨多糖（CA-Se）对K562人慢性髓源白血病细胞线粒体膜电位的影响，及对K562细胞的凋亡诱导作用。采用MTT比色法测定CA-Se对K562细胞的增殖抑制作用；Hoechst 33342/PI染色后于显微镜下观察细胞的形态变化；罗丹明-123染色后用流式细胞仪检测细胞线粒体膜电位的变化；采用免疫荧光法检测caspase-9蛋白表达水平，并用RT-PCR检测其基因的表达。结果表明：CA-Se可显著抑制K562细胞的增殖，且具有浓度依赖性和时间依赖性；经CA-Se作用后，细胞形态发生明显改变，细胞体积变小，细胞膜变得不规则，染色质固缩；对照组与CA-Se处理组的线粒体膜电位分别为96.10%和78.07%，膜电位下降；CA-Se处理后，K562细胞中caspase-9蛋白表达显著增加，其基因表达水平显著上升。说明硒酸软骨多糖可通过降低细胞线粒体膜电位，上调凋亡起始酶caspase-9的基因表达，激活caspase-9蛋白来诱导K562细胞凋亡。

The effect of selenic acid cartilage polysaccharide (CA-Se) on the mitochondrial membrane potential of K562 human chronic myeloid leukemia cells and on the induction of apoptosis of K562 cells were studied. The inhibitory effect of CA-Se on the proliferation of K562 cells was studied using the MTT (3,-(4,5-dimethylthiazol-2-y))-2,5-diphenyl tetrazolium bromide) colorimetric assay, while the changes in the morphological characteristics after Hoechst 33342/PI staining were observed under a microscope. The changes in the mitochondrial membrane potential (ΔΨm) after rhodamine-123 staining were assessed by flow cytometry (FCM), and the protein and gene expressions of caspase-9 were analyzed by immunofluorescence and real-time polymerase chain reaction (RT-PCR), respectively. The results showed that the proliferation of K562 cells was significantly inhibited by CA-Se in a dose- and time-dependent manner. After CA-Se treatment, the morphological characteristics of cells were dramatically changed, and a reduction in cell volume, irregularities in cell membranes, and chromatin condensation were observed. The ΔΨm values reduced after CA-Se treatment from 96.10% (the control) to 78.07% (CA-Se treatment). The protein and gene expressions of caspase-9 both increased significantly. All the results indicated that CA-Se can induce apoptosis of K562 cells by reducing the ΔΨm, upregulating the expression of the caspase-9 (initiator caspase) gene, and activating caspase-9 protein.

国家自然科学基金资助项目（31271975）