Ilya Zavodnik, Leu Zavodnik, Jolanta Kujawa, Jan Talar, Maria Bryszewska, Małgorzata Łukowicz, Iwona Pyszczek

Ilya Zavodnik, Leu Zavodnik, Jolanta Kujawa, Jan Talar, Maria Bryszewska, Małgorzata Łukowicz, Iwona Pyszczek – Membrane and cellular effects of red laser radiation on human erythrocytes sensitized with Zn-phthalocyanine. Fizjoterapia Polska 2002; 2(2); 145-153

Abstract
Background. There is increasing interest in photosensitizing dyes, used as effectors in photodynamic therapy and photosterilization of biological fluids. The plasma membrane of the cell appears to be the principal site of photodamage. The photohemolytic activity of the sensitizer can be used as a parameter of the dye’s photodynamic toxicity. The aim of the present study is to further characterize the mechanism(s) of cell damage caused by exposure to red laser (670 nm) emission in human erythrocytes sensitized by Zn-phthalocyanine, and to evaluate the role of different cell components in erythrocyte photostability. Material and methods. We measured the effect of various erythrocyte treatments on cell damage induced by laser irradiation: „light” and post-irradiated „dark” hemolysis, cellular glutathione oxidation, membrane lipid peroxidation, and membrane protein oxidation. Results. Laser irradiation of red blood cells sensitized by Zn-phthalocyanine caused the oxidation of membranous protein tryptophan and cysteine residues, fluidization of the membrane lipid bilayer, and lipid peroxidation. The rate of „light” hemolysis significantly increased with increasing pH from 6.8 to 8.5, and after cell membrane perturbations by alcohols or in the presence of dithiotreitol, which is thought to reduce thiol groups oxidized by photosensitization. Conclusions. Membrane lipid peroxidation, the thiol groups of membrane proteins, and intracellular glutathione oxidation do not participate in hemolysis induced by red light. Membrane band 3 proteins play a significant role in erythrocyte photostability.

Key words:
photosensitizing dyes, photohemolysis, photodynamic toxicity

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