胞内冰形成机理研究进展

Review of the Mechanism of Intracellular Ice Formation

在生物样本的低温保存过程中,胞内冰是造成细胞损伤的主要因素之一。影响胞内冰形成的因素包括降温速率、细胞对水分的渗透能力、细胞膜完整性、胞外冰及低温保护剂等。本文详细讨论并分析了目前有关胞内冰形成机制的主要理论:孔理论、SCN理论、VCN理论以及细胞膜受损理论,总结了胞内冰最新的研究进展。提出利用水通道阻断剂或基因敲除的方法来研究水通道蛋白和胞内冰形成的关系,指明胞内冰形成机制及今后的研究方向。

One of the important challenges in developing successful cryopreservation protocols for biological samples relies on avoiding the freezing damage imposed by the intracellular ice formation（ IIF）. Experimental studies have shown that the formation of a traceable quantity of IIF is lethal. This complex phenomenon is affected by various factors including the cooling rate,water transport,cell membrane integrity,extracellular ice,and cryoprotectant. The main goal of this work is to review the four classical intracellular ice formation theories that have been previously proposed： 1） external ice grows through pores in the cell membrane and catalyzes the IIF,2） external ice causes a conformational change in the cell membrane,transforming it into an effective heterogeneous form and causing IIF,3） the IIF is catalyzed heterogeneously through intracellular structures or homogeneously,and 4） the IIF is a result of plasma membrane damage. The latest experimental observations support the idea that the contact between the external ice and cell membrane leads directly or indirectly to the formation of intracellular ice. Aquaporins are likely a key factor affecting the IIF. The use of an aquaporin inhibitor and a gene knockout to study the IIF is also proposed in this article.