藏红花素对HL-60细胞增殖抑制和诱导凋亡作用及其机制

本研究探讨藏红花素(crocin)对人急性白血病细胞HL-60增殖抑制的影响及其促凋亡机制。测定HL-60细胞在不同浓度crocin作用后的生长曲线,用荧光显微镜观察细胞形态学变化,MTT法检测细胞的增殖情况,流式细胞术检测细胞周期分布,RT-PCR检测bcl-2、bax基因的表达。结果表明,不同浓度crocin作用后HL-60细胞生长明显受抑制,并呈现出剂量时间依赖关系。在0-5mg/ml范围内HL-60细胞凋亡率逐渐升高。当crocin浓度高于5mg/ml时,HL-60细胞凋亡率并没有升高,反而下降,表现为细胞坏死。流式细胞术检测结果显示,细胞周期被阻滞于G0/G1,且在5mg/ml时阻滞作用最明显。RT-PCR结果显示,bcl-2基因表达明显下调,bax基因表达上调。结论:crocin可诱导HL-60细胞凋亡,并对细胞周期起阻滞作用,其作用机制可能与bcl-2基因表达抑制及bax基因表达激活有关。

Proliferative Inhibition and Apoptotic Induction Effects of Crocin on Human Leukemia HL-60 Cells and Their Mechanisms

This study was to investigate the proliferative inhibition and apoptosis of human leukemia HL-60 cells induced by crocin and their possible mechanisms. The cell viability was tested by cell counting. The morphology of HL- 60 cells was observed by fluorescence microscopy. The MTT assay was used to evaluate the inhibitory effect of crocin on the growth of HL-60 ceils. Flow cytometry was used to measure the cell cycle. RT-PCR was used to detect bcl-2 and bax expression. The results indicated that the growth of HL-60 cells was inhibited remarkably in the dose and time dependent way. When the crocin concentration was higher than 5 mg/nd, the percentage of apoptotic HL-60 cells was not increased, on the contrary this percentage decreased, the cells manifested necrosis. Flow cytometry profiles revealed that ceils were blocked in G0/G1 phase, the cell proliferation was inhibited obviously at 5 mg/ml. RT-PCR detection revealed that the expression of bcl-2 was down-regulated strikingly and bax was up-regulated. It is concluded that the crocin can inhibit the proliferation of HL-60 cells effectively, and block cells in G0/G1 phase. The mechanisms by which crocin induced apoptosis in HL-60 cells may be related to the inhibition of bcl-2 and activation of bax.