THE GENERATION OF REACTIVE OXYGEN SPECIES BY CORD BLOOD NUCLEATED CELLS DURING CRYOPRESERVATION

The generation of reactive oxygen species in different populations of nucleated cells during cord blood cryopreservation was studied. Using cytometry with the 2′,7′-dichlorodihydrofluorescein diacetate dye we assessed the integral content of reactive oxygen species in various populations (lymphocytes, monocytes, granulocytes) of cord blood nucleated cells, depending on the method of isolation, treatment with cryoprotectant and freezing. Furthermore the activity of antioxidant enzymes prior to and after cryopreservation while the cells were loaded with exogenous reactive oxygen species, which source was hydrogen peroxide, was assessed. The results obtained showed that the isolation and cryopreservation of cord blood nucleated cells according to proposed method, which included the isolation of cells in polyglucinum and freezing with 5% DMSO did not result in a significant increase in level of intracellular reactive oxygen species. In addition the activity of antioxidant enzymes to exogenous hydrogen peroxide inactivation in cryopreserved cell was maintained at the level close to that in the native cord blood. Among all the populations of cord blood nucleated cells the granulocytes were the least resistant to cryopreservation effects.