Repin N V
Department of Cryomorphology, Institute for Problems of Cryobiology and Cryomedicine of the National Academy of Sciences of the Ukraine, Kharkov, Ukraine.
Cryo Letters. 2009 Jul-Aug;30(4):250-61.
The processes, occurring at the stage of temperature exposure under two-step freezing of human and hibernating ground squirrel erythrocytes were studied by electron-microscopic method of freeze-fracturing. For human erythrocytes the time of intracellular crystal dissolution in human erythrocytes made 30 min and this value was shown to be slightly depending on temperature within -20 to -35 degree C range. Erythrocyte membrane permeability for water within negative temperature range has been estimated. It was noted that the value of water membrane permeability coefficient obtained theoretically, taking into account experimental values of time of dissolution for intracellular ice crystals and cell dehydration, is quite well consistent with the reported data and equals to about 0.5 x E-13 (cubic m)/N/sec for human erythrocytes and E-13 (cubic m)/N/sec for hibernating ground squirrel cells. Under two-step freezing a temperature arrest results in a qualitative change of water exchange process between cell and its environment, and the exposure duration may serve as the measure for cell dehydration. According to the data of NMR "paramagnetic doping" and freeze-fracturing the erythrocyte membrane of hibernating ground squirrels is more permeable for water than human one.
采用冷冻断裂电子显微镜法研究了人及冬眠地松鼠红细胞两步冷冻温度暴露阶段发生的过程。对于人红细胞，细胞内冰晶溶解时间为30分钟，且该值在-20至-35摄氏度范围内略有温度依赖性。估算了负温度范围内红细胞膜对水的通透性。值得注意的是，理论上考虑细胞内冰晶溶解时间和细胞脱水的实验值得到的水膜通透系数值与报道数据相当吻合，人红细胞约为0.5×E-13（立方米）/牛顿/秒，冬眠地松鼠细胞为E-13（立方米）/牛顿/秒。在两步冷冻过程中，温度停滞导致细胞与其环境之间水交换过程的质的变化，暴露持续时间可作为细胞脱水的度量。根据核磁共振“顺磁掺杂”和冷冻断裂数据，冬眠地松鼠的红细胞膜对水的通透性比人红细胞更高。
