The distribution of phospholipids across erythrocyte membrane bilayer is asymmetrical. The present study reports the effect of malonyldialdehyde (MDA), a product of fatty acid peroxidation, on the organization of phosphatidylserine (PS) and phosphatidylethanolamine (PE) in human erythrocytes using a nonpermeable bee venom phospholipase A2 and trinitrobenzene-sulfonilic acid. MDA accumulation in the erythrocytes was accomplished both by its increased endogenous generation after exposure of cells to H2O2, as well as by the treatment of erythrocytes with exogenous authentic MDA. The above treatments resulted in a significantly increased movement of PS and PE from inner bilayer to outer bilayer, which had a highly positive correlation with the concentration of MDA in the erythrocyte membranes. Antioxidants vitamin E, butylated hydroxytoluene, and butylated hydroxyanisole inhibited the effect of H2O2 treatment on erythrocyte membrane lipid organization by scavenging fatty acid peroxidation and formation of MDA. Thus, lipid peroxidation and MDA accumulation can disturb organization of PS and PE in the human erythrocyte membrane bilayer.
Antioxidants Erythrocyte Membrane