Mugnano J A, Wang T, Layne J R, DeVries A L, Lee R E
Department of Zoology, Miami University, Oxford, Ohio 45056, USA.
Am J Physiol. 1995 Aug;269(2 Pt 2):R474-9. doi: 10.1152/ajpregu.1995.269.2.R474.
Despite recent reports that antifreeze glycoproteins (AFGPs) protect mammalian cells during low-temperature preservation, T. Wang, Q. Zhu, X. Yang, J. R. Layne, and A. L. DeVries (Cryobiology 31: 185-192, 1994) reported that AFGPs failed to protect rat hearts during freezing. Rather, the presence of AFGPs exacerbated cardiac damage after freezing. This study examined the effects of freezing (-4 degrees C) in the presence of AFGPs at the cellular level with the use of cryomicroscopy. Large, blunt ice crystals formed in the solutions without AFGPs and excluded most cardiomyocytes from the plane of ice formation. After thawing, cells appeared similar in morphology to unfrozen cells. Ice in 0.5 mg/ml AFGP solution was more dendritic and prismatic than ice formed in the absence of AFGPs. On thawing, many cells exhibited spontaneous contraction, resulting in cell death. Spicular ice formed rapidly in the 10 mg/ml AFGP solution. These needlelike ice crystals appeared to penetrate the cardiomyocytes, resulting in intracellular freezing followed by cell lysis. These AFGP-induced changes in ice crystal structure may account for the injury observed in whole heart and cardiomyocyte experiments.
尽管最近有报道称抗冻糖蛋白（AFGPs）在低温保存过程中可保护哺乳动物细胞，但T. Wang、Q. Zhu、X. Yang、J. R. Layne和A. L. DeVries（《低温生物学》31: 185 - 192, 1994）报道，AFGPs在冷冻过程中未能保护大鼠心脏。相反，AFGPs的存在加剧了冷冻后心脏的损伤。本研究使用低温显微镜在细胞水平上研究了在AFGPs存在下冷冻（-4℃）的影响。在没有AFGPs的溶液中形成了大而钝的冰晶，将大多数心肌细胞排除在冰形成平面之外。解冻后，细胞形态与未冷冻的细胞相似。0.5 mg/ml AFGP溶液中的冰比没有AFGPs时形成的冰更呈树枝状和棱柱状。解冻时，许多细胞表现出自发收缩，导致细胞死亡。在10 mg/ml AFGP溶液中迅速形成针状冰。这些针状冰晶似乎穿透了心肌细胞，导致细胞内结冰，随后细胞裂解。这些AFGPs诱导的冰晶结构变化可能解释了在全心脏和心肌细胞实验中观察到的损伤。
