A comparison of the effect of methyl-?-cyclodextrin on the osmotic fragility of ovine, bovine and human erythrocytes

Abstract

Cyclodextrins are used extensively in food, cosmetic, drug and chemical industries to increase aqueous solubility and stability, and reduce or eliminate the unpleasant taste and smell of many products. Experiments were conducted to examine the effect of a pre-haemolytic dose of methyl ?-cyclodextrin (MBCD) on the osmotic fragility of erythrocytes collected from sheep, cattle and humans. Heparinised blood collected from these three species were analysed within 3 h of collection. Erythrocyte suspensions were mixed with MBCD to give concentrations of 2 mM, 4 mM or 6 mM cyclodextrin. The mixtures were incubated for 30 min at 37°C and centrifuged. The osmotic fragility of re-suspended erythrocytes was measured. The incubation of MBCD with the erythrocyte suspensions induced a dose-dependent increase in the osmotic fragility of erythrocytes obtained from all three species. The beginning of haemolysis in control groups of sheep, cattle and humans occurred at 0.85%, 0.70% and 0.55% NaCl, respectively. However, haemolysis in the MBCD-treated groups began earlier than this in all the three species studied. The osmotic fragility of erythrocytes was significantly higher at NaCl concentrations of 0.70% (P > 0.01), 0.75% (P > 0.001) and 0.80% (P > 0.001) in sheep; 0.55% (P > 0.01), 0.60% (P > 0.001) and 0.65% (P > 0.01) in cattle; and 0.40% (P > 0.01), 0.45% (P > 0.001) and 0.50% (P > 0.01) in humans than in the controls. In conclusion, these results indicate that a pre-haemolytic dose of MBCD may also induce membrane disruption which elicits removal of membrane components from erythrocytes.