The Apoptosis Of Cord Blood Hematopoietic Cells Induced By Growth Factors Withdrawal And Effect Of Ginsenosides Rg1 And Rb1

Objective: To investigate the characterization of cord blood heraatopoietic cells during apoptosis induced by growth factors withdrawal and effect of ginsenosides Rgl and Rbl. Methods: Human cord blood CD34+ stem cells were purified and obtained sterilely. CD34+ cells (5 X lO⁴/ml) were expanded with StemSpan橲FEM serum-free medium containing cytokines TPO(50μg/L) and SCF(50μg/L) for 7 days. Then cells were isolated and incubated by growth factors deprivation for 1 day and 3 day. The experimental groups were respectively pretreated by Rgl (2.5mg/L 5mg/L l0mg/L) or Rbl ( 5mg/L l0mg/L) of different concentrations. Flow cytometry analysis was used to determine the purity of fresh CD34+ cells. During apoptosis, FITc-Annexin-V FCM analysis and Caspase-3 Colorimetric Assay were respectively used to determine cell apoptotic rate and relative expression of Caspase-3 protein. Results: The purity of MACS isolated CD34+ cells was (98. 28?. 62)%. The total number of 7-day-incubated cells with TPO and SCF was expanded up to 24.5-fold; The cell apoptotic rate was upregulated from (2. 69?. 43) % to (24. 79?. 80) % after growth factors deprivation for 1 day. Rgl andRbl pretreated groups reduced the cell apoptotic rate. After growth factors deprivation for 1 day and 3 day, relative expression of Caspase-3 protein was upregulated about 1-fold. During some concentrations of Rgl and Rbl pretreated, relative expression of Caspase-3 reduced. Conclusion: These results demonstrate that apoptosis of cord blood hematopoieticcells can be induced by loss of survival growth factors. During apoptosis, Caspase-3 is invoved in apoptosis but may not the only mechanism invoved.