Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, P.R. China.
Mol Med Rep. 2013 Jun;7(6):1938-44. doi: 10.3892/mmr.2013.1421. Epub 2013 Apr 10.
A picosecond pulsed electric field (psPEF) is a localized physical therapy for tumors that has been developed in recent years, and that may in the future be utilized as a targeted non‑invasive treatment. However, there are limited studies regarding the biological effects of psPEF on cells. Electric field amplitude and pulse number are the main parameters of psPEF that influence its biological effects. In this study, we exposed HeLa cells to a psPEF with a variety of electric field amplitudes, from 100 to 600 kV/cm, and various pulse numbers, from 1,000 to 3,000. An MTT assay was used to detect the growth inhibition, while flow cytometry was used to determine the occurrence of apoptosis and the cell cycle of the HeLa cells following treatment. The morphological changes during cell apoptosis were observed using transmission electron microscopy (TEM). The results demonstrated that the cell growth inhibition rate gradually increased, in correlation with the increasing electric field amplitude and pulse number, and achieved a plateau of maximum cell inhibition 12 h following the pulses. In addition, typical characteristics of HeLa cell apoptosis in the experimental groups were observed by TEM. The results demonstrated that the rate of apoptosis in the experimental groups was significantly elevated in comparison with the untreated group. In the treatment groups, the rate of apoptosis was greater in the higher amplitude groups than in the lower amplitude groups. The same results were obtained when the variable was the pulse number. Flow cytometric analysis indicated that the cell cycle of the HeLa cells was arrested at the G2/M phase following psPEF treatment. Overall, our results indicated that psPEF inhibited cell proliferation and induced cell apoptosis, and that these effects occurred in a dose-dependent manner. In addition, the results demonstrated that the growth of the HeLa cells was arrested at the G2/M phase following treatment. This study may provide a foundation for further in vivo experiments, and for the potential clinical application of psPEF in the treatment of cervical cancer.
皮秒脉冲电场（psPEF）是近年来发展起来的一种肿瘤局部物理治疗方法，未来可能被用作一种靶向非侵入性治疗方法。然而，关于 psPEF 对细胞的生物学效应的研究有限。电场幅度和脉冲数是影响 psPEF 生物学效应的主要参数。在这项研究中，我们用从 100 到 600 kV/cm 的各种电场幅度和从 1000 到 3000 的各种脉冲数对 HeLa 细胞进行了 psPEF 照射。MTT 检测法用于检测生长抑制率，流式细胞术用于检测 HeLa 细胞在处理后的凋亡发生和细胞周期。用透射电子显微镜（TEM）观察细胞凋亡过程中的形态变化。结果表明，细胞生长抑制率逐渐增加，与电场幅度和脉冲数的增加呈正相关，并在脉冲后 12 小时达到最大细胞抑制的平台。此外，通过 TEM 观察到实验组 HeLa 细胞凋亡的典型特征。结果表明，实验组的凋亡率明显高于未处理组。在处理组中，高幅度组的凋亡率高于低幅度组。当变量为脉冲数时，也得到了相同的结果。流式细胞术分析表明，HeLa 细胞的细胞周期在 psPEF 处理后被阻滞在 G2/M 期。总之，我们的结果表明 psPEF 抑制细胞增殖并诱导细胞凋亡，并且这些效应呈剂量依赖性。此外，结果表明 HeLa 细胞的生长在处理后被阻滞在 G2/M 期。这项研究可为进一步的体内实验以及 psPEF 在宫颈癌治疗中的潜在临床应用提供基础。
