Storey K B
Institute of Biochemistry, Carleton University, Ottawa, Ont., Canada.
Biochem Cell Biol. 1990 Apr;68(4):687-98. doi: 10.1139/o90-100.
For a wide variety of animals, winter survival in cold climates includes the ability to tolerate ice formation in extracellular body fluids. Among terrestrially hibernating vertebrates, freeze tolerance has been documented for five amphibian and two reptile species. These species may survive for days or weeks in a frozen state with no breathing and no heart beat, and with up to 65% of total body water as extracellular ice. The biochemical mechanisms involved in natural freeze tolerance include (i) the regulation of extracellular ice formation by proteinaceous ice nucleators in body fluids, (ii) the accumulation of high concentrations of low molecular weight carbohydrates as cryoprotectants to regulate cell volume reduction during freezing and stabilize macromolecular structure, and (iii) a well-developed ischemia tolerance that supports the survival of individual organs while frozen. The present article focuses on recent advances in our understanding of the biochemistry of natural freeze tolerance in lower vertebrates and the application of these studies to the improvement of cryopreservation technology for transplantable mammalian organs.
对于各种各样的动物来说，在寒冷气候中度过冬天的能力包括耐受细胞外体液中形成冰的能力。在陆地冬眠的脊椎动物中，已经有记录表明五种两栖动物和两种爬行动物具有耐冻能力。这些物种可以在冰冻状态下存活数天或数周，没有呼吸和心跳，全身多达65%的水分以细胞外冰的形式存在。自然耐冻所涉及的生化机制包括：（i）通过体液中的蛋白质类冰核剂调节细胞外冰的形成；（ii）积累高浓度的低分子量碳水化合物作为冷冻保护剂，以调节冷冻过程中的细胞体积减小并稳定大分子结构；（iii）发达的缺血耐受性，以支持单个器官在冷冻时存活。本文重点介绍了我们对低等脊椎动物自然耐冻生物化学的最新认识进展，以及这些研究在改进可移植哺乳动物器官冷冻保存技术方面的应用。
