ALUMINUM(III) INDUCES ALTERATIONS ON THE PHYSICAL STATE OF THE ERYTHROCYTIC MEMBRANE - AN ESR EVALUATION

The action of aluminum [Al(III)] as Al(acac)(3) on erythrocytes causes biophysical effects such as osmotic fragility and echino-acanthocytes formation [1]. In this paper, we present these effects in terms of va riation of membrane fluidity, together with findings regarding conform ational modifications of membrane proteins consequent to Al(III) expos ure, as well as the effects on the mobility of the membrane protein bo und sialic acid. To this end, we utilized ESR measurements of rabbits and humans erythrocytic ghosts after probing or labeling with suitable stable radicals used as spin probes or labels. Our results show that the lipophilic, hydrolytically stable toxicant Al(acac)(3) causes a re markable reduction of membrane fluidity in rabbit erythrocytes, an app reciable structural compacting effect on cytoskeletal and transmembran e proteins, as well as a reduction of rotational mobility of cell-surf ace sialic acid of human erythrocytes. (C) 1997 Elsevier Science Inc.