RESUMO
The antioxidant effects of near-infrared radiation (NIR) in vitro (700-200 nm) on human erythrocytes was studied as a continuation of our earlier studies. The changes of: ratio of hemolysis, electrokinetic potential, lipids peroxidation, autohemolysis, and fluidity of red cell lipid bilayer were studied for intact, irradiated, ozonated and irradiated, and ozonated erythrocytes. We revealed that, under in vitro condition, the oxidation of red cells by ozone decreased lipids' bilayer fluidity in the vicinity of the 5th carbon and increased fluidity on the 16th carbon level of hydrocarbon chains, induced autohemolysis, oxidized lipids, and changed the electrokinetic potential. However, when erythrocytes were exposed to near-infrared radiation (NIR) and later ozonated, measured parameters were the same as that for control cells kept in darkness or markedly less modified than that ozonated. In conclusion, these observations suggest protective action of NIR radiation on the erythrocyte membrane. The results support the idea that during exposition to NIR, dehydration process induces the photochemical dissociation oxyhemoglobin to deoxyhemoglobin. Deoxygenation leads to phosphorylation of cytoplasmic domain of band 3 at tyrosine 8 that strengthens its association with the spectrin network. An increased association between band 3 and the underlying skeleton elevated the cell membrane mechanical resistance that could protect them before autohemolysis. Also, weakening hydrogen bonds on the surface of erythrocyte membranes moderate the surface charge, lowering the accessibility of charged free radicals from ozone solution into cells.
