Influence of oxygen tension on the viscoelastic behavior of red blood cells
in sickle cell disease
GB Nash, CS Johnson and HJ Meiselman
Although the rheological behavior of sickle cell suspensions and of
hemoglobin S solutions is known to be strongly dependent on oxygen tension
(PO2), little data exist concerning the influence of PO2 on the
viscoelasticity of individual HbSS RBC. We have used micropipette
aspiration techniques to test the deformation response of both HbSS and
control HbAA RBC over a wide range of PO2 at 23 degrees C. Sickled,
spiculed HbSS cells were present for PO2 approximately less than 35 mm Hg;
for a number of these cells, the deformation response was essentially
elastic and an effective membrane rigidity (EMR) was calculated. EMR
increased with decreasing PO2 and was approximately 5 to 50 times higher
than the equivalent rigidity of oxygenated HbSS RBC. In addition, the rate
of membrane deformation was very slow for sickled cells; the half-time for
the deformation process increased as PO2 was lowered and was about two
orders of magnitude longer than the equivalent time for normal RBC. Other
sickled cells exhibited plastic deformation when subjected to comparable
deforming forces and experienced irreversible membrane deformation and
budding. At all PO2 levels tested, some HbSS RBC remained as discocytes;
these cells had normal membrane elasticity and membrane viscosity.
Furthermore, changes in PO2 did not affect the membrane properties of HbAA
RBC. Thus, gross abnormalities in the deformation response of HbSS RBC were
only detected after morphological sickling had occurred. These
abnormalities most likely arose from changes in the cytoplasmic HbS
viscoelasticity and, if present in vivo, would be expected to impair the
flow of HbSS cells in the microcirculation.
Volume 67,
Issue 1,
pp. 110-118,
01/01/1986
Copyright © 1986 by The American Society of Hematology
