Nonmonotonic trends in electrolyte-induced injury to rapidly cooled erythrocytes.

Rapid freeze-thaw injury to erythrocytes and erythrocyte ghosts has been shown to be strongly cation dependent. For the Group I ions this dependence is nonmonotonic in nature with injury increasing in the order Li+ less than Na+ less than Cs+ less than K+. Injury can be reduced by the inclusion in the freezing media of saccharide cryoprotectants or by the substitution with less injurious cations, e.g., Mg2+ or (CH3)4N+. In contrast to the situation observed with cations injury with anions follows Hofmeister lyotropic power series with injury increasing with decreasing hydrated ionic radius. Careful choice of electrolyte species allows injury to be reduced to levels comparable to that afforded by saccharide cryoprotectants. A possible mechanism for the nonmonotonic trends in injury observed with cations is considered.