Zolla L, Lupidi G, Marcheggiani M, Falcioni G, Brunori M
Department of Cell Biology, University of Camerino, Italy.
Biochim Biophys Acta. 1990 May 9;1024(1):5-9. doi: 10.1016/0005-2736(90)90202-y.
Moderate osmotic shocks of human erythrocytes by hypotonic dialysis (0.06 mosmol/kg) induce cell swelling and formation of pores, without causing apparent lysis. Using 125I-labeled macromolecules of different molecular weight and net charge, we followed the kinetics and efficiency of their encapsulation into erythrocytes. After a 20-30 min period of cell dialysis, macromolecules of up to 50 kDa begin diffusing into the swollen cells by a process which can be described by a first-order two-compartment kinetics. Adsorption to the external cell surface was insignificant, while adsorption to the inner membrane surface was substantial (15-20%) only for positively charged proteins, at physiological pH. After resealing, pores of a 12-14 kDa cut-off might remain open allowing some release of entrapped material (20-30%), depending on the final cytocrit, while the remaining might be associated with inner membrane or cytosolic components. Although the method of hypotonic dialysis is known to affect minimally the biophysical and immunological properties of red blood cell membranes, the interaction of encapsulated material with cell constituents would need to be further assessed when considering red cells as macromolecular carriers.
通过低渗透析（0.06 毫渗摩尔/千克）对人红细胞进行适度的渗透冲击会诱导细胞肿胀并形成孔，但不会导致明显的裂解。我们使用不同分子量和净电荷的 125I 标记的大分子，追踪它们被包封到红细胞中的动力学和效率。在细胞透析 20 - 30 分钟后，高达 50 kDa 的大分子开始通过一个可用一级双室动力学描述的过程扩散到肿胀的细胞中。在生理 pH 条件下，对细胞外表面的吸附微不足道，而仅对带正电荷的蛋白质而言，对内膜表面的吸附相当可观（15 - 20%）。重新封闭后，取决于最终的血细胞比容，截留分子量为 12 - 14 kDa 的孔可能会保持开放，从而允许一些被包封物质释放（20 - 30%），而其余的可能与内膜或胞质成分相关。尽管已知低渗透析方法对红细胞膜的生物物理和免疫学性质影响极小，但在将红细胞视为大分子载体时，包封物质与细胞成分的相互作用仍需进一步评估。
