Gabriel B, Teissié J
Laboratoire de Pharmacologie et de Toxicologie Fondamentales du CNRS, Département III: Glycoconjugués et Biomembranes, Toulouse, France.
Eur J Biochem. 1995 Mar 15;228(3):710-8. doi: 10.1111/j.1432-1033.1995.tb20314.x.
When electropulsed by short strong electric field pulses, cells can be permeabilized transiently (electropermeabilization). The transient electroinduced membrane restructuration which supports enhanced membrane permeability is topologically well defined on the surface of the cell. Exchange of polar species only takes place on the part of the cell surface which is controlled by the field intensity. Electropermeabilization is a stress for the cell and metabolic responses associated with this stress must be studied. A key point is to discover whether this stress affects the whole cell surface or especially the permeabilized part. This was investigated by photochemical time-dependent methodology. Analysis of the photooxidation reaction of 5-(N-hexadecanoyl)-aminofluorescein, an interfacial light-sensitive fluorescent probe, inserted into the Chinese hamster ovary cell membrane showed that the rate of reaction was accelerated when the cell population was electropermeabilized. This increase in the rate constant depended on the field strength. A theoretical approach suggested that modulation of the photooxidation reaction was restricted to the electropermeabilized part of the cell surface. The difference of reactivity could be correlated with an activator effect of oxygen-reactive species generated by an electro-induced oxidative jump and suggested that these species were localized in the permeabilized part of the plasma membrane. Using fluorescence digitized videomicroscopy imaging on a single cell, such spatial heterogeneity of the photooxidation reaction was indeed directly observed when the cell was electropermeabilized. There was heterogeneous compartmentation of the membrane reaction into two independent domains with specific reactivity. The direct observation is that long-lived electropermeabilization only affects a restricted part of the pulsed cell surface, from both a structural and a metabolic point of view.
当受到短而强的电场脉冲电脉冲作用时，细胞可被瞬时通透化（电穿孔）。支持增强膜通透性的瞬时电诱导膜重构在细胞表面的拓扑结构上是明确的。极性物质的交换仅发生在受场强控制的细胞表面部分。电穿孔对细胞来说是一种应激，必须研究与这种应激相关的代谢反应。关键在于发现这种应激是影响整个细胞表面还是特别影响通透化的部分。这是通过光化学时间依赖性方法进行研究的。对插入中国仓鼠卵巢细胞膜的界面光敏荧光探针5-（N-十六烷酰基）-氨基荧光素的光氧化反应分析表明，当细胞群体进行电穿孔时，反应速率加快。速率常数的这种增加取决于场强。一种理论方法表明，光氧化反应的调节仅限于细胞表面的电穿孔部分。反应性的差异可能与电诱导氧化跃迁产生的氧反应性物种的激活作用相关，并表明这些物种定位于质膜的通透化部分。在单个细胞上使用荧光数字化视频显微镜成像，当细胞进行电穿孔时，确实直接观察到了光氧化反应的这种空间异质性。膜反应存在异质性分隔，分为具有特定反应性的两个独立区域。直接观察结果是，从结构和代谢角度来看，长时间的电穿孔仅影响脉冲细胞表面的有限部分。
