AJP - Regulatory, Integrative and Comparative Physiology, Vol 269, Issue 2 474-R479, Copyright © 1995 by American Physiological Society
Antifreeze glycoproteins promote intracellular freezing of rat cardiomyocytes at high subzero temperatures
J. A. Mugnano, T. Wang, J. R. Layne Jr, A. L. DeVries and R. E. Lee Jr
Department of Zoology, Miami University, Oxford, Ohio 45056, USA.
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.
