脉冲电场对人红细胞膜结构影响的冷冻断裂研究

对外加脉冲电场处理的人红血球冷冻断裂和蚀刻的复型观察中发现在强电场(3KV/cm)作用下,细胞周围有颗粒状和纤维状结构。结合SDS电泳分析证明了它们是由于在电场作用下,红血球膜的带3蛋白和膜骨架蛋白(血影蛋白)脱出的结果。在强电场作用下,由于膜蛋白和膜骨架蛋白的脱出造成了对细胞膜的损伤,使细胞膜稳定性降低,细胞易变形和形成伪足。由于膜蛋白的脱出,多余的自由脂质进入细胞质内而形成泡状结构。外电场改变了蛋白-蛋白以及蛋白-脂分子间的作用可能是电穿孔的主要机理。本文还对当前公认的冷冻断裂中所观察到的膜中间颗粒的来源提出了疑问,并提出了它们还可能与冰晶有关。而冰晶的形成又与膜的亲水与疏水性有关。

FREEZE-FRACTURING STUDIES ON HUMAN ERYTHROCYTE MEMBRANES EFFECTED BY EXTERNAL PULSED ELECTRICAL FIELD

Electron microscopic observations made on the freeze-fracturing replica of plasma membranes of human erythrocytes exposed to external pulsed electrical field have shown that under experimental conditions, some particles and fibers appear around the cells pulsed by higher intensities than 3 KV/cm. Electrophoretical analysis for the cell suspensions has proved that some of these particles and fibers are membrane proteins and membrane skeleton proteins escaped from cells. On account of this, the stability of cell membrane decreases and the cells are easy to change their shapes and to form pseudopodium like st- ructures and protein free membrane lipids tend to form vesicular structure in cytop-lasma. The changes of protein-protein interactions and protein-lipid interactions caused by electrical field are considered as the dominating mechanism of cell membrane electroporation. An argument about intra-membrane particles (IMPS) and other possibilities of the contributions to IMPS, for instance, ice crystals formation which related to membrane hydrophilic or hy-drophobic properties were discussed in this paper.