THE OSMOTIC RUPTURE HYPOTHESIS OF INTRACELLULAR FREEZING-INJURY

A hypothesis of the nature of intracellular ice formation is proposed in which the osmotically driven water efflux that occurs in cells duri ng freezing (caused by the increased osmotic pressure of the extracell ular solution in the presence of ice) is viewed as the agent responsib le for producing a rupture of the plasma membrane, thus allowing extra cellular ice to propagate into the cytoplasm. This hypothesis is devel oped into a mathematical framework and the forces that are present dur ing freezing are compared to the forces which are required to rupture membranes in circumstances unrelated to low temperatures. The theory i s then applied to systems which have been previously studied to test i mplications of the theory on the nature of intracellular ice formation . The pressure that develops during freezing due to water flux is foun d to be sufficient to cause a rupture of the plasma membrane and the t heory gives an accurate description of the phenomenology of intracellu lar ice formation.