Effects of Pb2+ on human erythrocyte membrane and molecular models.

Lead has no biological function; however, low, and particularly, high levels of exposure have a number of negative consequence for human death. Despite the number of reportes about lead toxicity, very little information has been obtained regarding its effects on cell membranes. For this reason, the structural effects of lead on the human erythrocyte membrane was investigated. This aim was attained by making lead ions interact with intact erythrocytes, isolated unsealed erythrocyte membrane (IUM) and molecular models. The latter consisted of bilayer of dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE), representing phospholipid classes located in the outer and inner monolayer of the human erythrocyte memebrane. The results, obtaine by electronmicroscopy, fluorescence spectroscopy and X-ray diffraction, indicated that (a) lead particles adhered to external and internal surfaces of the humanerythrocyte membrane; (b) lead ions disturbed the lamellar organization of IUM and DMPC large unilamellar vesicles (LUV) and (c) induced considerable molecular disorder in both lipid multilayers, the effects being much more pronounced in DMPC.