Flow behaviour of rigid red blood cells in the microcirculation.
Flow behaviour of rigid (diamide treated) red blood cells (RBC) was investigated in anaesthetised rats and isolated rat mesentery, supplemented by pressure-flow curves in small bore glass tubes. It was shown that (1) Diamide treated cells, the shear modulus of which is increased, were not eliminated from the circulation of rats within an experimental time of 4 h. (2) At normal arterial pressure, an exchange of native for diamide treated red blood cells only slightly reduced RBC flow velocity in capillaries of the mesentery of anaesthetised rats. (3) Flow velocity of stiffened red blood cells was drastically reduced at low driving pressure (hypotension). Many capillaries became irreversibly clogged and flow did not resume with normalisation of the arterial blood pressure. (4) In the capillaries of the isolated mesentery, no difference in resistance to flow was observed between treated and control cells as long as steady state velocities were compared. This is in accordance with results obtained in glass tubes above wall shear stresses of 0.05 Pa. At stenoses, however, where RBC's undergo transient deformations, the passage times of treated cells were longer than those of untreated cells. From this it is concluded that not only the elastic properties but also the viscous properties of the red cell membrane are changed by diamide treatment and that the dynamic response of the red cell during transient deformations may limit the ability of the cell to negotiate the microcirculation.
D000818:Animals; D001783:Blood Flow Velocity; D003958:Diamide / Q000494:pharmacology; D004907:Erythrocyte Deformability; D004912:Erythrocytes / Q000187:drug effects; D006874:Hydrostatic Pressure; D066298:In Vitro Techniques; D008833:Microcirculation / Q000502:physiology*; D010477:Perfusion; D051381:Rats; D012039:Regional Blood Flow; D013152:Splanchnic Circulation
D003958:Diamide