Purpose: To investigate the extent of γ-irradiation-induced oxidative membrane damage and antioxidant activity of quercetin in long-term, cold stored (4°C) acid-citrate-dextrose- preserved human red blood cells (RBC).
Materials and methods: The extracellular activity of lactate dehydrogenase (LDH) was measured to assess RBC membrane integrity. Lipid peroxidation and reduced glutathione (GSH) levels were quantified by thiobarbituric acid-reactive substances (TBARS) and Ellman's reagent, respectively.
Results: During storage of non-irradiated RBC (up 21 days) the LDH activity in the supernatant increased with time. In contrast to a low dose of ionizing radiation (30 Gy), irradiation at higher, but still clinically relevant doses, of 40-50 Gy resulted in elevation of the post-storage extracellular LDH activity. Quercetin (2-50 μM) dissolved in dimethyl sulfoxide (DMSO) significantly increased the LDH release in the irradiated and non-irradiated RBC, reflecting an increase of RBC membrane permeability. In the presence of ethanol as a solvent quercetin protected RBC against storage-induced oxidative damage - it inhibited the LDH release, GSH depletion, and lipid peroxidation.
Conclusion: The level of protection offered by quercetin against the radiation- and storage-induced oxidative damage to RBC does not seem to be sufficient to warrant its application as an additive for conservation purposes. The findings indicate that the solvent can modulate a response of RBC to water-insoluble antioxidants changing their properties from anti-oxidative to pro-oxidative.
Keywords: Red blood cell; oxidative damage; quercetin; transfusion; γ-irradiation/storage.