Erythrocyte deformability in aging

Blood viscosity and the deformability and other properties of erythrocytes were compared among 60-, 150-, 320- and 710-day-old rats. Blood viscosity was remarkably higher in the 320- and 710-day old rats than in those 60- and 150 days' old. Measurement by the capillary centrifugal method showed that the deformability of erythrocytes is significantly decreased with age. The increase in blood viscosity with aging could be attributed to the decrease in erythrocyte deformation. Osmotic fragility and the number of higher density erythrocytes also increase with age. The negative surface charge in erythrocytes obtained from old rats was higher than in those from younger rats.