DIFFERENTIAL-EFFECTS OF SULFATE AND SULFOBUTYL ETHER OF BETA-CYCLODEXTRIN ON ERYTHROCYTE-MEMBRANES IN-VITRO

The hemolytic activity of beta-cyclodextrin (beta-CyD) on rabbit eryth rocytes was reduced by the introduction of negatively-charged groups o nto the hydroxyls of beta-CyD; the membrane disrupting abilities decre ased in the order of beta-CyD > 2-hydroxypropyl-beta-CyD (HP-beta-CyD) > sulfobutyl-beta-CyD (SB-beta-CyD) >> beta-CyD sulfate (S-beta-CyD). Under pre-hemolytic concentrations, both beta-CyD and SB-beta-CYD indu ced shape changes of membrane invagination on the erythrocytes. In sha rp contrast, S-beta-CyD showed biphasic effect on the shape of the ery throcytes; i.e. the crenation at relatively low concentrations and the invagination at higher concentrations. The S-beta-CyD-induced membran e crenation arose from a direct action on the membranes rather than ce ll metabolism-mediated effects. Unlike beta-CyD, S-beta-CyD was found to bind to the erythrocytes and may be confined to the outer surface o f the membrane bilayer, which may expand the exterior layer relative t o the cytoplasmic half, thereby inducing the cells to crenate. On the other hand, the membrane invagination mediated by the three beta-CyDs was initiated by extracting specific membrane lipids from the cells, d epending upon their inclusion abilities, subsequently leading to the l ysis of the cells. These results indicate that SB-beta-CyD and S-beta- CYD interact with the erythrocyte membranes in a differential manner a nd possess lower membrane disrupting abilities than the parent beta-Cy D and HP-beta-CyD.