中文摘要：

为研究陡脉冲电场的诱导凋亡作用,以体外人肝癌细胞SMMC-7721为实验对象,采用Annexin V-FITC/PI双染色并利用流式细胞术检测磷脂酰丝氨酸（PS）外翻,采用琼脂糖凝胶电泳检测DNA降解片段化。实验发现,陡脉冲电场能有效（P〈0.05）地使PS外翻,并且微秒级陡脉冲（μsSPEF）比纳秒级陡脉冲（nsSPEF）更有效（P〈0.05）;陡脉冲电场能使DNA降解片段化,且nsSPEF比μsSPEF更有效。实验结果表明,陡脉冲电场能有效诱导体外人肝癌细胞凋亡,其机理与陡脉冲电场非热效应及其频谱特性有关。μsSPEF主要作用于细胞膜,而可能通过外源性通路诱导细胞凋亡;nsSPEF主要作用于细胞核和线粒体等胞内细胞器,可能通过内源性通路诱导细胞凋亡。实验结果为陡脉冲电场杀伤肿瘤细胞的机制和参数选择提供了依据。

英文摘要：

The purpose of this study is to investigate the effects of steep pulsed electric fields （SPEF） on the apoptosis of human liver cancer cell SMMC-7721 in vitro. We studied phosphatidylserine （PS） externalization using flow cytometry （SMMC-7721 stained with Annexin V-FITC/PI ） and DNA fragmentation assay by agarose gel electrophoresis. Three groups of experiment were performed ： control group, μsSPEF treated group （ SPEF with electric field intensity of 200V/cm and duration of 1.3 μs） and nsSPEF treated group （SPEF with electric field intensity of 600 V/cm and duration of 100 ns）. The experiment results by flow cytometry showed that SPEF was effective （ P 〈 0.05） to induce PS translocation and μsSPEF was more effective （ P 〈 0.05） than that of nsSPEF. On the contrary, nsSPEF induced DNA fragmentation more notably than that of μsSPEF. These experiment results showed that SPEF was effective to induce apoptosis of human liver cancer cell SMMC-7721 in vitro. It was a result of nonthermal effects of SPEF and its frequency spectrum characteristics,μsSPEF and nsSPEF contained different frequency components, which would selectively target different parts of cell. t~sSPEF mainly acted on plasma membrane and activated the extrinsic apoptosis pathway, which might induce PS externalization effectively. On the other hand, nsSPEF permeated plasma membrane and mainly affected intracellular organelle and activating the intrinsic apoptosis pathway, which might induce DNA fragmentation markedly.