title: Melatonin protects against lipid peroxidation and membrane rigidity in erythrocytes from patients undergoing cardiopulmonary bypass surgery.
abstract: The first aim of this study was to test whether there are changes in erythrocyte lipid peroxidation products and membrane fluidity during cardiac surgery involving cardiopulmonary bypass. Secondly, in vitro tests were performed to examine whether melatonin alters induced lipid peroxidation and reduced membrane fluidity in erythrocytes from these patients. Fifteen patients undergoing cardiac surgery involving cardiopulmonary bypass (CPB) were selected. Five blood samples were taken at different times during surgery for analysis of thiobarbituric acid reactive substances (TBARS) content and membrane fluidity of the erythrocytes. TBARS are an index of the level of lipid peroxidation. The results revealed an increase in TBARS levels and a parallel decrease in erythrocyte membrane fluidity (increased membrane rigidity) after the onset of CPB with respect to the reference sample. Likewise, in vitro induction of lipid peroxidation in the erythrocyte samples from CPB patients followed a similar pattern. The changes in TBARS levels and membrane fluidity were suppressed by pre-incubation of erythrocytes with melatonin prior to the induction (by 70 microm Fe2+ + 250 microm ascorbate) of lipid peroxidation in a concentration-dependent manner. The results constitute a persuasive argument for the use of melatonin for preventive and therapeutic purposes during CPB.
authors.affiliation: Department of Physiology, Institute of Nutrition and Food Technology, University of Granada, Granada, Spain.
authors.forename: Julio J
authors.initials: JJ
authors.lastname: Ochoa
authors.forename: María J
authors.initials: MJ
authors.lastname: Vílchez
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Palacios
authors.forename: Joaquín J
authors.initials: JJ
authors.lastname: García
authors.forename: Russel J
authors.initials: RJ
authors.lastname: Reiter
authors.forename: Antonio
authors.initials: A
authors.lastname: Muñoz-Hoyos
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D002462:Cell Membrane / Q000187:drug effects; D001026:Coronary Artery Bypass; D004912:Erythrocytes / Q000187:drug effects*; D006801:Humans; D015227:Lipid Peroxidation / Q000187:drug effects*; D008550:Melatonin / Q000494:pharmacology*; D008560:Membrane Fluidity / Q000187:drug effects*; D008875:Middle Aged
chemical_list: D000975:Antioxidants; D008550:Melatonin