We hypothesized that the results of red blood cell mechanical stability test show interspecies differences. The comparative investigations were performed on blood samples obtained from rats, beagle dogs, pigs and healthy volunteers. Mechanical stress was applied in nine combinations: 30, 60 or 100 Pa shear stress for 100, 200 or 300 seconds. Generally, rat erythrocytes showed the highest capability of resistance. With the applied combinations of mechanical stress pig erythrocytes were the most sensitive. On human erythrocytes 60 Pa for 200 s was the minimum combination to result significant deformability deterioration. By increasing the magnitude and duration of the applied mechanical stress we experienced escalating deformability impairment in all species. 100 Pa shear stress for 300 seconds on human erythrocytes showed the largest deformability impairment. The mechanical stability test results were also dependent on osmolality. At hypoosmolar range (200 mOsmol/kg) the mechanical stress improved EI data mostly in rat and porcine blood. At higher osmolality (500 mOsmol/kg), the test did not show detectable difference, while in 250-300 mOsmol/kg range the differences were well observable. In summary, erythrocytes' capability of resistance against mechanical stress shows interspecies differences depending on the magnitude and duration of the applied stress, and on the osmolality.
Keywords: Red blood cell deformability; comparative hemorheology; mechanical stability; membrane stability; osmotic gradient ektacytometry.