中频交变电流抑制肿瘤细胞的体外增殖

目的:初步探究新型物理治疗技术中频交变电流对肿瘤细胞和正常细胞体外存活率的影响;设置不同实验参数(频率、电流、时间),观察影响效果;针对实验结果,分析中频交变电流抑制肿瘤细胞体外增殖的可能机制。方法:将对数生长期的细胞悬液接种于24孔培养板,贴壁后(24 h)施加不同参数的中频电流刺激,噻唑蓝(MTT)法检测细胞存活率;以人乳腺癌细胞MCF-7为例,观察中频交变电流对细胞生存环境温度和pH的影响,Annexin V-FITC/PI双染法流式细胞术定量检测细胞凋亡/死亡情况,扫描电子显微镜和透射电子显微镜观察细胞结构变化。结果:中频交变电流能降低肿瘤细胞的体外存活率,诱导其凋亡,但不影响正常细胞(L929)存活率;MCF-7细胞体外实验最适参数是100 kHz,50 mA,每天30 min;电刺激后MCF-7细胞表面微绒毛减少,细胞线粒体肿胀,有多泡体及溶酶体形成。结论:中频交变电流能抑制肿瘤细胞增殖,但不影响正常细胞(L929);抑制效果和电刺激的频率、电流和时间有关;抑制机制可能是中频交变电流能够诱导细胞凋亡,影响细胞膜表面蛋白功能,但不影响细胞生存环境。中频交变电流抑制肿瘤体外增殖为实体瘤等增生性疾病的治疗提供了新的思路。

Inhibiting Tumor Cells with Alternating Micro-current at Intermediate Frequency in Vitro

Objective： The aim of the present study is to investigate the inhibitory efficacy of alternating current at intermediate frequency （ACIF） on tumor cells and normal cells in vitro. Influencing effect of different parameters （frequency, electric current, duration） was observed. Then the possible mechanism of ACIF inhibition on tumor cell proliferation in vitro was analyzed based on the result of the experiments. Methods： The cells in logarithmic growth phase were planted in 24-well plates. ACIF of different parameters was applied after cells attachment. The survival rates to cells were determined by methyl thiazolyl tetrazolium （MTT） method. In human breast cancer cells （MCF-7）, for example, effect of ACIF on temperature and pH of cell survival environment was observed. Apoptosis or death grates of MCF-7 cells were evaluated by Annexin V-FITC and PI double labeled flow cytometry. Scanning electron microscopy and transmission electron microscopy were applied to examine the changes in morphology and structural of MCF-7 cells, in order to evaluate cells apoptosis. Results： ACIF could decrease survival rates of tumor cells and induce apoptosis, but does not affect normal cells （L929） survival. The optimum stimulation parameters for MCF-7 cells are 100 kHz, 50 mA, lasting 30 min every day. Results of scanning electron microscopy and transmission electron microscopy showed that MCF-7 cells after treatment were damaged seriously, including reduction of microvilli, mitochondrial swelling, multi-vesicle body and lysosome. Conclusion： ACIF can inhibit tumor cell proliferation, but not normal cells. The effects are consistent with the frequency, electric current and duration. ACIF may act in two possible modes： inducing apoptosis and affecting function of membrane proteins. And this conclusion provides a new way for proliferative diseases.