Pegg D E
Medical Cryobiology Unit, Department of Biology, University of York, York, United Kingdom.
Semin Reprod Med. 2002 Feb;20(1):5-13. doi: 10.1055/s-2002-23515.
The ability of glycerol to protect cells from freezing injury was discovered accidentally. The subsequent development of cryopreservation techniques has had a huge impact in many fields, most notably in reproductive medicine. Freezing injury has been shown to have two components, direct damage from the ice crystals and secondary damage caused by the increase in concentration of solutes as progressively more ice is formed. Intracellular freezing is generally lethal but can be avoided by sufficiently slow cooling, and under usual conditions solute damage dominates. However, extracellular ice plays a major role in tissues. Cryoprotectants act primarily by reducing the amount of ice that is formed at any given subzero temperature. If sufficient cryoprotectant could be introduced, freezing would be avoided altogether and a glassy or vitreous state could be produced, but osmotic and toxic damage caused by the high concentrations of cryoprotectant that are required then become critical problems. The transport of cryoprotectants into and out of cells and tissues is sufficiently well understood to make optimization by calculation a practical possibility but direct experiment remains crucial to the development of other aspects of the cryopreservation process.
甘油保护细胞免受冷冻损伤的能力是偶然发现的。随后冷冻保存技术的发展在许多领域产生了巨大影响，最显著的是在生殖医学领域。冷冻损伤已被证明有两个组成部分，冰晶造成的直接损伤以及随着越来越多的冰形成，溶质浓度增加所导致的继发性损伤。细胞内结冰通常是致命的，但可以通过足够缓慢的冷却来避免，在通常情况下，溶质损伤占主导。然而，细胞外结冰在组织中起主要作用。冷冻保护剂主要通过减少在任何给定的零下温度下形成的冰量来发挥作用。如果能够引入足够的冷冻保护剂，就可以完全避免结冰，并产生玻璃态或玻璃化状态，但所需的高浓度冷冻保护剂所引起的渗透和毒性损伤就会成为关键问题。冷冻保护剂进出细胞和组织的运输已得到充分了解，使得通过计算进行优化成为一种实际可能，但直接实验对于冷冻保存过程其他方面的发展仍然至关重要。
