Bone marrow stromal stem cells lack of specific surface marker and their identification challenges scholars all the time.OBJECTIVE:
To explore the culture condition for clonal isolation of human bone marrow stromal stem cells (BMSCs) and identify their surface markers and differentiation potentials.METHODS:
Human bone marrow was taken and BMSCs were isolated using density gradient centrifugation. Clone-like cells were selected by single cell limiting dilution. The surface antigens of the cloned BMSCs were analyzed by flow cytometry and immunocytochemistry. Multi-differentiation capacities were evaluated by inducing BMSCs into osteoblasts, chondrocytes and cadiocytes. RT-PCR and immunocytochemistry were applied to detect the three mutli-differentiations.RESULTS AND CONCLUSION:
Single cell-derived BMSCs could be expanded to passage 28 in vitro which still maintaued active proliferation ability. The expanded BMSCs expressed CD29, CD44, CD106, but not CD14, CD34, CD45, HLA-DR. They could be induced to differentiate into osteoblasts, chondrocytes and cadiocytes. These findings suggest that cloned BMSCs can maintain the phenotypes of stem cells during in vitro culture.