Effects of Cytochalasin B on Osmotic Fragility and Deformability of Human Erythrocytes

Abstract

The presence of cytochalasin B is associated with an increase in the osmotic fragility of human erythrocytes as determined by measuring the extent of hemolysis in solutions of various osmolarities. Erythrocytes exposed to cytochalasin and subsequently washed displayed the same osmotic fragility as controls. Cytochalasin similarly increased deformability as indicated by measurement of pressure differences required to draw single cells into a micropipette of 2.0–2.5 μm diameter. The required pressure, reduced in the presence of cytochalasin, was the same as for controls after the cells treated with cytochalasin were washed.The reversible increases in osmotic fragility and deformability are interpreted as indicative of a reduction in tensile strength of the plasma membrane, perhaps associated with a loss of microfilaments.