A theoretical model of intracellular devitrification.
A theoretical model of intracellular devitrification.
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DOI：
10.1006/cryo.2001.2318
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发表时间：
2001-05
期刊：
影响因子：
2.7
通讯作者：
J. Karlsson
中科院分区：
文献类型：
--
作者：
J. Karlsson
在通过冷冻或玻璃化冷冻保存的细胞的加温期间，细胞内溶液的脱玻璃化可引起显著损害。鉴于以前的理论研究失透没有考虑细胞脱水对细胞内冰形成的影响，提出了一个新的模型，该模型耦合膜限制的水传输方程，经典的成核理论和扩散限制的晶体生长理论。该模型被用来探讨细胞脱水在甘油存在下冷冻的人角质形成细胞失透中的作用。数值模拟表明，在冷却过程中的水运输影响随后的细胞内冰的形成在变暖，正确地预测观察到的临界升温速率随冷却速率的增加而增加。然而，对于细胞的膜运输活化能小于约50 kJ/mol，脱玻作用也受到细胞脱水在升温过程中，导致逆转的冷却速率和临界升温速率之间的关系。因此，对于低升温速率（对于角质形成细胞小于10 ° C/min），在升温期间形成的细胞内冰晶的大小和总体积分数随着升温速率的降低而降低，并且临界升温速率随着冷却速率的增加而降低。水的运输细胞内成核和晶体生长的动力学的影响进行了阐明，通过比较模拟的细胞变暖与模拟的失透在H（2）O-NaCl-甘油液滴的恒定大小和组成。这些研究表明，细胞内成核速率对细胞脱水的敏感性低于晶体生长速率。所提出的理论方法可用于设计和优化冻融方案。
Devitrification of the intracellular solution can cause significant damage during warming of cells cryopreserved by freezing or vitrification. Whereas previous theoretical investigations of devitrification have not considered the effect of cell dehydration on intracellular ice formation, a new model which couples membrane-limited water transport equations, classical nucleation theory, and diffusion-limited crystal growth theory is presented. The model was used to explore the role of cell dehydration in devitrification of human keratinocytes frozen in the presence of glycerol. Numerical simulations demonstrated that water transport during cooling affects subsequent intracellular ice formation during warming, correctly predicting observations that critical warming rate increases with increasing cooling rate. However, for cells with a membrane transport activation energy less than approximately 50 kJ/mol, devitrification was also affected by cell dehydration during warming, leading to a reversal of the relationship between cooling rate and critical warming rate. Thus, for low warming rates (less than 10 degrees C/min for keratinocytes), the size and total volume fraction of intracellular ice crystals forming during warming decreased with decreasing warming rate, and the critical warming rate decreased with increasing cooling rate. The effects of water transport on the kinetics of intracellular nucleation and crystal growth were elucidated by comparison of simulations of cell warming with simulations of devitrification in H(2)O-NaCl-glycerol droplets of constant size and composition. These studies showed that the rate of intracellular nucleation was less sensitive to cell dehydration than was the crystal growth rate. The theoretical methods presented may be of use for the design and optimization of freeze-thaw protocols.