【摘要】 背景:目前已有报道证实,电脉冲能诱导癌细胞发生凋亡。目的:测试在不同参数电脉冲处理下人肝癌细胞的凋亡效应以及线粒体跨膜电位变化。设计、时间及地点:对照观察实验,于2007-03/2008-03在重庆大学生物流变科学与技术教育部重点实验室、电气工程学院输配电装备及系统安全与新技术国家重点实验室完成。材料:SMMC-7721人肝癌细胞与HL-7702正常人肝细胞均购自中国典型培养物保藏中心。方法:采用场强、脉宽分别为200V/cm,1.8μs;250V/cm,1.8μs;600V/cm,120ns的电脉冲分别处理人正常肝细胞与肝癌细胞1min,用流式细胞术及DNALadder检测2种细胞的凋亡情况;用激光共聚焦显微镜对处理后的细胞线粒体跨膜电位变化进行实时观测。主要观察指标:不同参数电场下SMMC-7721细胞的凋亡率,SMMC-7721在不同参数电场下刺激10min的线粒体跨膜电位变化。结果:场强200V/cm及250V/cm,脉冲1.8μs的电场可以诱导肝癌细胞凋亡;120ns,600V/cm的电场未明显诱导癌细胞凋亡。DNALadder进一步证实了电脉冲诱导的细胞凋亡效应,但是120ns,600V/cm的电脉冲处理下的癌细胞却呈现出更多的DNA片段。对线粒体跨膜电位变化实时观测结果表明,电脉冲的处理降低了癌细胞线粒体跨膜电位,120ns,600V/cm的电场比1.8μs,200V/cm及250V/cm的电场更能有效的降低线粒体跨膜电位(67.09%,23.71%,28.44%)。结论:细胞的凋亡效应和线粒体跨膜电位的变化依赖于脉宽和场强等电场参数。窄脉冲对胞内结构的作用较宽脉冲更明显,而线粒体跨膜电位的降低并不能直接说明细胞发生了凋亡效应。更多还原

【Abstract】 BACKGROUND: Previous reports revealed that electric pulses can induce apoptosis in cancer cells. OBJECTIVE: To observe the effects of different pulses on the apoptosis and mitochondrial transmembrane potential of human cancer cells, in addition, to investigate the apoptosis effects of electric pulse. DESIGN, TIME AND SETTING: A controlled and observational experiment was performed at the Key Laboratory of Biorheological Science and Technology and State Key Laboratory of Power Transmission Equipment & System Security and New Technology, Ministry of Education between March 2007 and March 2008. MATERIALS: Human hepatoma cell SMMC-7721 and normal human liver cell HL-7702 was purchased from China Center for Type Culture Collection. METHODS: SMMC-7721 and HL-7702 were stimulated with electric pulse (200 V/cm, 1.8 μs; 250 V/cm, 1.8 μs; 600 V/cm, 120 ns, respectively) for 1 minute, flow cytometry and DNA ladder were used to determine the apoptosis of cells, meanwhile, real-time changes of mitochondrial transmembrane potential were investigated by confocal microscopy when cells exposed to electric fields. MAIN OUTCOME MEASURES: The apoptosis rate of SMMC-7721 cells and changes of mitochondrial transmembrane potential of SMMC-772 after 10 minutes stimulation was investigated when cells exposed to different electric fields. RESULTS: The 1.8 μs, 200 V/cm and 250 V/cm electric fields could induce cells apoptosis, while 120 ns, 600 V/cm pulses didn’t have significant apoptotic effect on cells. Cells apoptosis was confirmed by DNA ladder. When cells were treated with pulses in 600 V/cm, 120 ns, and the cleavage of DNA was different from the cells treated with 1.8 μs pulses. More low-molecular-weight DNA fragments were extracted in this cell group. And the electric stimulation decreased mitochondrial transmembrane potential. Interestingly, the mitochondrial transmembrane potential decreased more significantly in cells that were exposed to the 120 ns, 600 V/cm electric fields (67.09%) compared to the cells in 1.8 μs, 200 V/cm and 250 V/cm (23.71% and 28.44% respectively). CONCLUSION: Electric pulses can induce cell apoptosis and decrease the mitochondrial transmembrane potential, which depending on the duration and electric intensity of electric pulses. Moreover, shorter pulses have more effect on intracellular structure. However, the change of mitochondrial transmembrane potential is not directly related to cell apoptosis.更多还原