Department of Biology, University of Saskatchewan, Saskatoon, SK, Canada.
Chemical, Biological & Environmental Engineering, Oregon State University, Corvallis, OR, USA.
Cryobiology. 2022 Dec;109:72-79. doi: 10.1016/j.cryobiol.2022.09.001. Epub 2022 Sep 18.
Successful cryopreservation requires the addition of cryoprotective agents (CPAs). The addition of permeating CPAs, such as glycerol, is associated with some risk to the cells and tissues. These risks are both related to the CPA themselves (CPA toxicity) and to the volume response of the cell (osmotic damage). To minimize the potential for damage during cryopreservation, mathematical models are often employed to understand the interactions between protocols and cell volume responses. In the literature, this volume response is usually captured using ideal and dilute approximations of chemical potential and osmolality, an approach that has been called into question for cells in high concentrations of CPAs. To address this, the relevance of non-ideal and non-dilute models has been explored in a number of cell types in the presence of permeating CPAs. However, it has not been explored in erythrocytes, which have a cytosolic hemoglobin content of more than 20% by volume and are cryopreserved in 40% glycerol. Because hemoglobin has been suggested to be a highly non-ideal solute, if the non-ideal and non-dilute transport model is relevant to any cells, it should be relevant to erythrocytes. Here we investigate the use, and accuracy, of both the dilute and non-dilute models in predicting cell volume changes during CPA equilibration in erythrocytes, and demonstrate that using published values for the non-ideal and non-dilute model, applied to erythrocytes, leads to model predictions inconsistent with experimental data, whereas dilute approximations align well with experimental data.
成功的冷冻保存需要添加冷冻保护剂（CPAs）。添加渗透型 CPAs，如甘油，会给细胞和组织带来一些风险。这些风险既与 CPA 本身（CPA 毒性）有关，也与细胞体积反应（渗透损伤）有关。为了最大限度地减少冷冻保存过程中的潜在损伤，通常采用数学模型来了解方案与细胞体积反应之间的相互作用。在文献中，通常使用化学势和渗透压的理想和稀溶液近似来捕获这种体积反应，这种方法已经受到高浓度 CPAs 下细胞的质疑。为了解决这个问题，在存在渗透型 CPAs 的情况下，许多细胞类型都已经探索了非理想和非稀溶液模型的相关性。然而，在红细胞中尚未进行探索，红细胞的胞质血红蛋白含量超过体积的 20%，并在 40%甘油中冷冻保存。由于血红蛋白被认为是一种高度非理想的溶质，如果非理想和非稀溶液传输模型与任何细胞相关，那么它应该与红细胞相关。在这里，我们研究了稀溶液和非稀溶液模型在预测红细胞中 CPA 平衡期间细胞体积变化中的应用和准确性，并证明，使用已发表的非理想和非稀溶液模型值应用于红细胞，会导致模型预测与实验数据不一致，而稀溶液近似值与实验数据很好地吻合。
