人参总皂甙对HL-60细胞凋亡相关基因bax、bcl-xl表达的影响

本研究探讨人参总皂甙对凋亡相关基因表达的影响及其诱导HL-60细胞凋亡的作用机制。用人参总皂甙0、100、200、400、800及1600μg／ml作用于HL-60细胞48小时。用荧光显微镜检测HL-60细胞形态的变化，流式细胞仪、DNA凝胶电泳检测HL-60细胞凋亡，RT—PCR检测bax、bcl—xl基因表达的变化。结果表明：人参总皂甙浓度在100—400μg／ml时，HL-60细胞凋亡逐渐增加，可见典型的凋亡细胞形态和明显的DNA梯度。在该浓度范围内，bax表达逐渐增加、而bcl—xl表达逐渐减少；当人参总皂甙浓度大于400μg／ml时，出现细胞坏死．细胞凋亡下降．结论：一定浓度的人参总皂甙能诱导HL-60细胞发生凋亡，且细胞凋亡率与人参总皂甙浓度呈一定的量效依赖关系，bax、bcl—xl基因的表达变化在人参总皂甙诱导HL-60细胞凋亡可能起重要作用。

Effect of Total Saponins of Panaxginseng on bax and bcl-xl Gene Expression in HL-60 Cells

The aim of this study was to investigate the effect of the total saponins of Panaxginseng (TSPG) on cells expression of apoptosis-related genes bax and bcl-xl in HL-60 cells and its mechanism inducing apoptosis of HL-60 cells. The morphology of HL-60 cells was observed under normal and fluorescence microscopes; the percentage of apoptotic HL-60 cells was assayed by flow cytometry and the DNA ladder was observed by DNA agarose gel electrophoresis; the expression changes of bax and bcl-xl mRNAs were detected by RT-PCR after HL-60 cells were treated with TSPG at final concentrations of 0, 100, 200, 400, 800 and 1600 microg/ml for 48 hours. The results showed that the percentage of apoptotic HL-60 cells went up as the dose increased, the typical apoptotic cell morphology and the appearance of apoptotic DNA ladder could be observed when treated with 0 - 400 microg/ml TSPG for 48 hours. At the same time and same range of concentration, the expression of bax mRNA increased and the bcl-xl expression decreased gradually. When higher than 400 microg/ml of TSPG was used, cell necrosis appeared and the percentage of apoptotic HL-60 cells even decreased. It is concluded that the apoptosis or necrosis in HL-60 cells can be induced by TSPG at certain range of concentration, and the percentage of apoptosis is dose-dependent. The effect on up-regulation of bax mRNA and down-regulation of bcl-xl mRNA probably play an important role in apoptosis of HL-60 cells indnced by TSPG.