Experiments have shown that both elastic and viscous components in the sackled hemoglobin solution increase in magnitude due to the polymerization when the oxygen tension decreases. However, the relative contributions of the red cell membrane and the internal hemoglobin solution to total cell rheological behavior is still unknown. A mathematical model based on previously published experimental research is newly developed to study that question. The flow of sickled red blood cells in a narrow capillary is modeled by a series of deformable circular cylinders in a rigid circular tube. Each cylinder consists of an elastic membrane filled with a viscoelastic interior. The viscoelastic interior represents the properties of sickled hemoglobin solution containing both solid and fluid phases at various oxygen tensions in an average sense. The suspending plasma is assumed to be an incompressible Newtonian fluid and it may be regarded as a pulsatile Stokes flow at given frequency and mean velocity. The calculated ratio of resistance to the flow with the deformable cell at different oxygen levels to that with rigid cell is obtained. The membrane effect is included by assuming different values of membrane rigidity. The results demonstrate that cell becomes significantly less deformable when oxygen tension (PO 2) drops below 25-30 mmHg (a critical level) if the membrane rigidity is taken as a constant representative of a normal cell. The critical level of oxygen tension shifts upward if the cell membrane increases its rigidity during sickling. The study illustrates the striking dependence of sickle cell deformability on the oxygen tension during polymerization.
|Original language||English (US)|
|Number of pages||1|
|Journal||Annals of Biomedical Engineering|
|State||Published - 1991|
All Science Journal Classification (ASJC) codes
- Biomedical Engineering