The hypotonic hemolysis and the protective action of lysophosphatidylcholine

Lysophosphatidylcholine (LPC) protected against hypotonic hemolysis during rapid swelling of erythrocytes in spherocytic concentrations without any increase in the maximal cell volume. The total prelytic potassium release was increased, but the prelytic potassium release per cell was the same or decreased in the presence of LPC. The comparison of measured and calculated cell volume increase suggested that the prelytic potassium release must have been connected with a considerable sodium influx suggesting serious damage of the cell membrane already during swelling in the absence of LPC. Gradual swelling shifted hemolysis to more dilute solutions and LPC did not further increase the shift. We suggest that LPC protects the erythrocytes against hypotonic hemolysis during rapid swelling via a prevention of the initial membrane damage through altering the interaction between lipid bilayer and membrane cytoskeleton in the same way as occurs during incubation in a medium with low ionic strength.