Towhidi Leila, Kotnik Tadej, Pucihar Gorazd, Firoozabadi S M P, Mozdarani Hossein, Miklavcic Damijan
Department of Medical Physics, Tarbiat Modares University, Tehran, Iran.
Electromagn Biol Med. 2008;27(4):372-85. doi: 10.1080/15368370802394644.
We present a study of the variability of the minimal transmembrane voltage resulting in detectable electroporation of the plasma membrane of spherical and irregularly shaped CHO cells (we denote this voltage by ITVc). Electroporation was detected by monitoring the influx of Ca(2+), and the transmembrane voltage was computed on a 3D finite-elements model of each cell constructed from its cross-section images. We found that ITVc was highly variable, particularly in irregularly shaped cells, where it ranged from 512-1028 mV. We show that this range is much too large to be an artifact due to numerical errors and experimental inaccuracies, implying that for cells of the same type and exposed to the same number of pulses with the same duration, the value of ITVc can differ considerably from one cell to another. We also observed that larger cells are in many cases characterized by a higher ITVc than a smaller one. This is in qualitative agreement with the reports that higher membrane curvature facilitates electroporation, but quantitative considerations suggest that the observed variability of ITVc cannot be attributed entirely to the differences in membrane curvature.
我们展示了一项关于最小跨膜电压变异性的研究，该电压会导致球形和不规则形状的中国仓鼠卵巢（CHO）细胞的质膜发生可检测到的电穿孔（我们将此电压记为ITVc）。通过监测Ca(2+)的流入来检测电穿孔，并根据从每个细胞的横截面图像构建的三维有限元模型计算跨膜电压。我们发现ITVc高度可变，特别是在不规则形状的细胞中，其范围为512 - 1028 mV。我们表明，由于数值误差和实验不准确性，这个范围太大以至于不可能是假象，这意味着对于相同类型且暴露于相同数量、相同持续时间脉冲的细胞，ITVc的值在不同细胞之间可能有很大差异。我们还观察到，在许多情况下，较大的细胞比较小的细胞具有更高的ITVc。这在定性上与更高的膜曲率促进电穿孔的报道一致，但定量分析表明，观察到的ITVc变异性不能完全归因于膜曲率的差异。
