alternation in erythrocyte enzyme antioxidant activity during blood storage

background: blood is permanently exposed to oxidation stress and therefore has a high antioxidants capacity. many different factors increasing the demand for the antioxidant capacity can be observed in the stored blood of donors. consequently, damage to erythrocytes by free radicals may occur. so it is useful to control the alternation of anti-oxidant enzymes in stored blood at different days of storage. the aim of the present study was to determine the alternation of erythrocyte superoxide dismutase and glutathione peroxidase enzyme activities in stored blood. material and methods: blood samples were obtained from 67 donors with average age of 26 years. samples were collected in cpda-1 anticoagulation solution. erythrocyte superoxide dismutase and glutathione peroxidase enzyme activities were determined using kei satoh method and kits from randox. the measurements were performed at the days 1, 7, 14, 21, 28 and 35 of storage. the blood bags were stored after each sampling at 4◦c. data were analyzed using analytical variance statistical test and spss version16 software. results: the erythrocyte levels of erythrocyte superoxide dismutase and glutathione peroxidase enzyme activities decreased significantly at the day 14th (p<0.001) of storage compared to day 1. conclusion: our results suggest that during blood storage, antioxidant defense in erythrocytes were depleting gradually depending on the day of storage. based on our finding a 14 days period can be considered a safe storage limit for transfusion in relation to oxidative stress on the rbcs in storage medium. key words: red blood cell, oxidative damage, antioxidant enzymes, blood storage.