Isolation Of Bone Marrow Mesenchymal Stem Cells In Adults By Immunomagnetic Selection

Objective To isolate and purify homogeneous adult bone marrow mesenchymal stem cells(BMSCs) quickly by immunomagnetic selection.Methods Human mononuclear cells(MNCs) were isolated by density centrifugation with Percoll gradient from adult bone marrow sample, and cultured and proliferated in L-DMEM. The MNCs fell into 2 groups. Routine plastic adherence culture was performed in one group, and the other group was further screened for Stro-1~+ cells by immunomagnetic selection technique. The 2 groups were assessed for their morphologic and biologic characteristics. The cell surface phenotype and cell cycle distributing were investigated by flow cytometry. The morphological features were observed through phase contrast microscope. The proliferative ability and growth state were detected with cell adhension rate curve, growth curve, fold increase curve. Osteogenic induction was conducted on the two groups of cells, their osteogenic ability were studied with alkaline phosphatase(ALP) staining, von-kossa staining of calcified nodules and energy dispersive X-ray analysis(EDXA).Result Bone marrow mesenchymal stem cells were obtained from adult bone marrow by immunomagnetic selection. To compare with the BMSCs collected by plastic adherence, the cells we isolated by immunomagnetic selection technique grew better in unique clone without round cells mingled, and had the character of higher cell adhension rate. The cells we isolated by immunomagnetic selection were capable of proliferating to 10~6-10~7 cells. The immunomagnetic selection technique had little effect on cell cycle. The cells selected by the immunomagnetic selection had the ability of differentiating to osteogenic cells by cultured with remineralization solution.Conclusion Immunomagnetic selection of bone marrow Stro-1~+ cells makes it possible to obtain highly purified and active human adult bone marrow mesenchymal stem cells.