Objective: To cultivate hematopoietic stem/progenitor cells (CD34(+)CD38(-)) isolated from umbilical cord blood (UCB) long for the observation of cell growth and expansion in vitro, surface marker expression, and chromosomal complements.
Methods: By flow cytometry CD34-FITC and CD38-PE labeled CD34(+) and CD38(-) stem/progenitor cells were isolated from UCB. The cells were cultivated in vitro for 6 months in a stem cell culture system with addition of six kinds of cell growth factors (IL-3, IL-6, GM-CSF, Epo, SCF, IGF-1). One month after cultivation, cultured cells were investigated for surface marker expression by flow cytometry and karyotype by G banding method.
Results: After 7-12 days cultivation, the CD34(+)CD38(-) stem/progenitor cells began proliferation. The proliferation rate and the peak proliferation duration were greater in 1 cell/well cultivation conditions than in 10 cells/well. The cells remained CD34(+)CD38(-) and their karyotypic characteristics remained unchanged.
Conclusion: CD34(+)CD38(-) stem/progenitor cells from UCB may provide a larger than original amount of stem/progenitor cells for transplantation after long-term cultivation in vitro.