Effect of cryopreservation on umbilical blood cells and its mechanism / 中南大学学报(医学版)

ABSTRACT

Objective:To evaluate the effect of cryopreservation on clonogenic ability and apoptosis rate of mono-nuclear cells and CD34+cells in umbilical blood (UB), and to choose the index to present the freezing injury and optimize the cryopreservation of UB. Methods:hTe mono-nuclear cells (MNC) and CD34+cells were separated from UB and frozen.Atfer 30 days, they were thawed in warm water. Clonogenic capacity and clonogenic recovery before and atfer the cryopreservation was compared. We also used Annexin V-FITC-PI to investigate the apoptosis rate of the cells before and atfer the cryopreservation of these 2 types of cells. Results:hTe number of colony forming unit-granulocyte/monocyte (CFU-GMs) was not changed atfer freezing and thawing in both MNCs and CD34+cells, while the number of colony forming unit-granulocyte, erythrocyte, monocyte and megakaryocyte (CFU-GEMM) was obviously reduced after freezing in CD34+cells. The 2 types of cryopreserved cells had certain degree of apoptosis before the cryopreservation. MNC-type cryopreservation increased the cells apoptosis a little, while CD34+-type cryopreservation increased more. Conclusion:hTe cells have certain degree of apoptosis before the cryopreservation. hTe freezing and thawing procedure does affect the early stage progenitor cells-CFU-GEMM in the CD34+-type cryopreserved cells in UB. hTe damage may be induced by the cell apoptosis.