Human red cells under hypertonic conditions; A model system for investigating freezing damage: 1. Sodium chloride

Abstract

Human red cells were exposed to unbuffered hypertonic solutions of sodium chloride for 1 hr at 0 °C to investigate their response to conditions similar to those experienced during freezing without the added effect of dilution (thawing). Because of the detrimental effect of high g on cells in hypertonic sodium chloride, separations were done at 2000 g. Cell water was measured in weight terms using a quench-corrected calibrated tritium technique, and sodium and potassium were assayed by atomic absorption spectroscopy. Up to 1500 mosmolal, as the cell water was withdrawn, intracellular potassium was retained reaching a maximum concentration of 0.31 moles/kg water. By 2000 mosmolal (an external sodium concentration of 1.20 moles/kg water) potassium had begun to leave the cell and sodium to enter (0.26 moles/kg water). Also at 2000 mosmolal the mass of water in the cell was 0.36 of that in the isotonic cell and the intracellular hemoglobin concentration had reached 57% w/w. The membrane potential (calculated from chloride ion distribution) had reached a minimum of 19.0 mV (inside negative) and the percentage hemolysis was 3%. These results demonstrate the occurrence and extent of the cation leak in red cells in hypertonic sodium chloride together with other measurements on the state of the cells when the leak takes place.