Background: Heparinised blood was exposed to osmotic lysis in hypotonic buffered saline to evaluate erythrocyte membrane stability. When K3 EDTA blood was used, it added more to the ionic content of blood than heparin. The influence of suspending media's ionic strength on the osmotic stability of Sahel goat erythrocytes was investigated by replacing the ionic saline with non-ionic saccharide (sucrose or glucose) and assessing the effect of using EDTA blood instead of heparinised blood.
Results: The erythrocyte osmotic fragility curve in saline was hyperbolic even when the ionic concentration was reduced by 50% with saccharides. Haemolysis was higher with EDTA than heparinised blood at saline concentrations of 90 and 150-180 mosmol/L. The fragility curve was sigmoidal and shifted to the left when saline was completely substituted with a saccharide. The non-ionic saccharides increased erythrocyte osmotic resistance linearly (r=0.88; p<0.02) from median to minimal hyposmolarities (150-300 mosmol/L) and reduced the osmolyte concentration at median fragility by 36%. No effect occurred at <30-120 mosmol/L and >90% fragility; and saccharide concentrations were almost non-lytic at comparable saline concentrations evoking <10% haemolysis. Fragilities were neither affected by period (30-60 min) of incubation nor the type of saccharide used.
Conclusions: In this study, the variation in osmotic stability of caprine erythrocytes was linked to ionic strength of the suspending extracellular media which seemed to exert an influence through transmembrane ion fluxes and regulatory volume changes in erythrocytes.