Abstract:Hydrated and dehydrated red cell samples were prepared from normal human red cells using the antibiotic nystatin. Furthermore, a series of red cell samples exposed to elevated temperature (20-50°C, 10 min) were prepared. The osmotic fragility and deformability of these red cells were then measured, using the coil planet centrifuge system and the capillary tube centrifugal technique, respectively. The osmotic fragility of nystatin-treated red cells decreased and the deformability increased as dehydration of red… Show more
“…RBCs from α II β I mice show significantly less resistance to hemolysis with 50% lysis at 150 mOsm/kg in contrast to 50% lysis at 130 mOsm/kg of RBCs from WT mice. Resistance to hemolysis is primarily defined by the cell surface area/volume ratio (cell sphericity) ( 29 , 30 ), and we conclude that increased osmotic fragility arises from the increased sphericity of α II β I cells, consistent with their decreased cell surface area. Figure 2 Effect of modified α II β I on membrane stability.…”
Spectrin tetramers of the membranes of enucleated mammalian erythrocytes play a critical role in red blood cell survival in circulation. One of the spectrins, aI, emerged in mammals with enucleated red cells after duplication of the ancestral a-spectrin gene common to all animals. The neofunctionalized aI-spectrin has moderate affinity for bI-spectrin, whereas aIIspectrin, expressed in nonerythroid cells, retains ancestral characteristics and has a 10-fold higher affinity for bI-spectrin. It has been hypothesized that this adaptation allows for rapid make and break of tetramers to accommodate membrane deformation. We have tested this hypothesis by generating mice with high-affinity spectrin tetramers formed by exchanging the site of tetramer formation in aI-spectrin (segments R0 and R1) for that of aII-spectrin. Erythrocytes with aIIbI presented normal hematologic parameters yet showed increased thermostability, and their membranes were significantly less deformable; under low shear forces, they displayed tumbling behavior rather than tank treading. The membrane skeleton is more stable with aIIbI and shows significantly less remodeling under deformation than red cell membranes of wild-type mice. These data demonstrate that spectrin tetramers undergo remodeling in intact erythrocytes and that this is required for the normal deformability of the erythrocyte membrane. We conclude that aI-spectrin represents evolutionary optimization of tetramer formation: neither higher-affinity tetramers (as shown here) nor lower affinity (as seen in hemolytic disease) can support the membrane properties required for effective tissue oxygenation in circulation.
“…RBCs from α II β I mice show significantly less resistance to hemolysis with 50% lysis at 150 mOsm/kg in contrast to 50% lysis at 130 mOsm/kg of RBCs from WT mice. Resistance to hemolysis is primarily defined by the cell surface area/volume ratio (cell sphericity) ( 29 , 30 ), and we conclude that increased osmotic fragility arises from the increased sphericity of α II β I cells, consistent with their decreased cell surface area. Figure 2 Effect of modified α II β I on membrane stability.…”
Spectrin tetramers of the membranes of enucleated mammalian erythrocytes play a critical role in red blood cell survival in circulation. One of the spectrins, aI, emerged in mammals with enucleated red cells after duplication of the ancestral a-spectrin gene common to all animals. The neofunctionalized aI-spectrin has moderate affinity for bI-spectrin, whereas aIIspectrin, expressed in nonerythroid cells, retains ancestral characteristics and has a 10-fold higher affinity for bI-spectrin. It has been hypothesized that this adaptation allows for rapid make and break of tetramers to accommodate membrane deformation. We have tested this hypothesis by generating mice with high-affinity spectrin tetramers formed by exchanging the site of tetramer formation in aI-spectrin (segments R0 and R1) for that of aII-spectrin. Erythrocytes with aIIbI presented normal hematologic parameters yet showed increased thermostability, and their membranes were significantly less deformable; under low shear forces, they displayed tumbling behavior rather than tank treading. The membrane skeleton is more stable with aIIbI and shows significantly less remodeling under deformation than red cell membranes of wild-type mice. These data demonstrate that spectrin tetramers undergo remodeling in intact erythrocytes and that this is required for the normal deformability of the erythrocyte membrane. We conclude that aI-spectrin represents evolutionary optimization of tetramer formation: neither higher-affinity tetramers (as shown here) nor lower affinity (as seen in hemolytic disease) can support the membrane properties required for effective tissue oxygenation in circulation.
“…Antibiotics like adriamycin [13], mefanamic acid [14], and nystatin [15] have been reported to alter the erythrocyte cell membrane, thereby increasing fragility and hemolysis. Erythromycin causes cardiac toxicity [16] as well.…”
Ciprofloxacin, Erythromycin and Norfloxacin are potent anti-microbials. These antibiotics, besides affecting bacteria, also exert toxic effects on mammalian cells. The present work was undertaken to study the effect of these antibiotics on the osmotic fragility profile of erythrocytes and the protective role played by vitamin supplementation, which exerts a stabilizing effect on the erythrocytes making them more resistant to lysis under hypotonic stress. The protective effect of β-carotene and L-ascorbic acid was significant (p < 0.01) at 0.1 mM and 0.01 mM concentrations. No significant effect was observed at lower concentrations. The free radical scavenging activity and effect of these vitamins on membrane fluidity and permeability may explain the protective role against the damage induced by the antibiotics on the erythrocytes membrane.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
