Abstract

Cryoprotective agents (CPAs) used to protect erythrocytes during freezing can affect the structural and functional parameters of the membrane, which have an impact on cell viability. The purpose of the study was to examine the effect of glycerol and PEG on the externalization of phosphatidylserine (PS) on the surface of erythrocytes, as well as to determine the role of Ca²⁺ ions and ATP-dependent processes in the regulation of transmembrane lipid asymmetry in the presence of these CPAs. It was found that the glycerol effect on erythrocytes does not lead to PS externalization. Maintaining the activity of scramblases and flipases in erythrocytes in the presence of glycerol at the level of control parameters allows them to respond similar to native cells to an increase in [Ca²⁺]_in caused by the ionophore A23187 and blocking of ATPase reactions caused by vanadate. The PEG effect contributes to the disruption of the PS distribution in the membrane due to changes in the activity of lipid translocases. However, activation of scramblases and/or inhibition of flipases under the PEG effect does not reach maximum values, as evidenced by an increase in the amount of erythrocytes with externalized PS under cell loading with Ca²⁺ by ionophore and inhibition of ATP-dependent reactions by vanadate. The effect of PEG on the lipid asymmetry of erythrocyte membranes is apparently mediated by its impact on the Ca²⁺ level in the cells. Disturbance of the structural parameters of the membrane due to the PS redistribution in the PEG presence, that distinguish it from the glycerol effect, can cause instability of cryopreserved erythrocytes under physiological conditions in vitro.

中文翻译：

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甘油和聚乙二醇存在下人红细胞膜脂质不对称分布的调控

摘要

冷冻过程中用于保护红细胞的冷冻保护剂（CPA）会影响膜的结构和功能参数，从而影响细胞活力。该研究的目的是检验甘油和PEG对红细胞表面磷脂酰丝氨酸（PS）外在化的影响，以及确定Ca ²⁺离子和ATP依赖性过程在跨膜调节中的作用。这些CPA存在时脂质不对称。已发现甘油对红细胞的作用不会导致PS外部化。在甘油存在的情况下，在控制参数水平上将红细胞中的scramblases和flipase的活性维持在允许的水平，这使它们对[Ca ²⁺ ]增加的反应类似于天然细胞。_在所造成的离子载体A23187和由钒ATP酶反应的阻断。由于脂质转座酶活性的变化，PEG作用有助于破坏膜中PS的分布。但是，PEG效应下的scramblases激活和/或对转移酶的抑制作用没有达到最大值，这是由离子载体在Ca ²⁺加载细胞的情况下具有外在PS的红细胞数量增加以及对ATP依赖性反应的抑制所证明的。钒酸盐 PEG对红细胞膜脂质不对称性的影响显然是由其对Ca ^2+的影响所介导的单元格中的水平。由于PEG存在时PS的重新分布而导致的膜结构参数紊乱（将其与甘油效应区分开来）会在体外生理条件下引起冷冻保存的红细胞不稳定。