A possible role of cold-induced ionic stress in cold-induced cell death.

ABSTRACT

Analysis of experimental results and published data within the framework of the suggested mathematical model of ion-osmotic homeostasis revealed the dependence of a variety of cell parameters on temperature. It was shown that the cold-induced drastic increase in the basal concentration of cytoplasmic Ca was determined, on the one hand, by the suppression of transport processes responsible for Ca removal from the cytoplasm, and, on the other hand, by the increase of calcium fluxes, both from the outer medium and from cell organelles. The cold-induced variation in the ratio of permeabilities for Na and K ions was found, which can be due to the activation of different calcium- and potential-dependent channels or by formation of membrane defects. Besides the flow of calcium ions through appropriate selective channels, its delivery into the cytosol through membrane defects actively induced by cell cooling can not be excluded. Formation of nonselective transmembrane channels was promoted by lipid peroxidation and proteolysis induced by an increase in the basal concentration of calcium. The new approaches to protecting the cell from cold injury are discussed.