Erythrocyte deformability and its hemorheological consideration

The suspension of hardened erythrocytes (red blood cells) differs from the suspension of normal erythrocytes with respect to their rheological behavior. The deformability of normal and hardened erythrocytes (obtained by heating blood at 49°C or by incubating erythrocytes in a solution of hydrogen peroxide) was measured with a slit diffractometer and erythrocyte suspension viscosity was measured with a rotational viscometer. We found that when erythrocytes were heated at 49°C, with much less deformability than normal erythrocytes, their suspension viscosity was almost the same as the normal blood viscosity at high shear rates, whereas when erythrocytes were incubated in a solution of hydrogen peroxide, with an intermediate decrease of deformability, their suspension viscosity was greatly increased. The present study concluded that not all rigid cells cause an increase in blood viscosity at high shear rates, and therefore that decreased cell deformability is not always a good indicator of high-shear blood viscosity.