柚皮素诱导K562细胞凋亡与Caspase-3／Caspase-8酶活性及FAS／FASL蛋白表达的关系

本研究旨在探讨柚皮素（naringenin）在体外诱导K562细胞凋亡及其相关机制。采用体外培养K562细胞，用不同浓度的柚皮素处理；用MTT法测定细胞增殖抑制率；流式细胞仪检测柚皮素作用后细胞凋亡率；透射电子显微镜观察柚皮素对K562细胞形态学的影响；caspase分光光度计法检测柚皮素作用后细胞内caspase-3和csa—pase-8活性的改变；细胞免疫化学染色检测柚皮素作用后细胞内FAS和FASL的表达。结果表明：柚皮素对K562细胞具有增殖抑制作用，并呈浓度和时间依赖性（P〈0．05）；在柚皮素作用下，出现典型亚G1峰，细胞凋亡率随柚皮素浓度的增高而增高（P〈0．05）；电子显微镜下细胞形态呈现凋亡征象；随着柚皮素浓度的增高，细胞内caspase-3和caspase-8酶活性增高（P〈0．05），FAS表达上升，FASL表达下降（P〈0．05）。结论：柚皮素在体外对K562细胞有诱导凋亡作用，而提高FAS的表达，降低FASL的表达，诱导caspase-3和caspase-8活化，可能是其作用机制。

Relation of Apoptosis of K562 Cells Induced by Naringenin In Vitro to Enzyme Activity Changes of Caspase-3 and Caspase-8 and Expression of FAS/FASL Proteins

The objective of this study was to investigate the apoptosis-inducing effect and underlying mechanism of naringenin (NGEN) on K562 cells in vitro. The inhibition of NGEN on K562 cells was evaluated by means of MTT assay so as to observe the cytotoxicity of NGEN; The morphological changes of the cells treated by NGEN were observed by transmission electron microscope; cell apoptosis rate influenced by NGEN was assessed by flow cytometry; the enzyme activity changes of caspase-3 and caspase-8 in the process of NGEN-induced K562 apoptosis were detected by Caspase Colorimetric Assay Kit; immunohistochemistry technique was used to detect FAS, FASL protein expression in K562 cells. The results showed that the growth of cells was inhibited by NGEN in dose-and time-dependent manners (p<0.05); NGEN-induced K562 cells apoptosis and sub-G1 peak was observed; some typically early and final phase changes of cell apoptosis were revealed under transmission electron microscope; the enzyme activity of caspase-3 and caspase-8 and the expression of FAS remarkably increased, meanwhile the expression of FASL was down-regulated (p<0.05). It is concluded that NGEN exerts anti-cancer effect by inducing K562 cell apoptosis, and the regulation of the expression of FAS and FASL. The caspase-3 and caspase-8 co-pathway brings about one of the mechanisms.