The experimental study for the repair of the osteochondral defect by Mesenchymal stem cells using cell sorter

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Over the past decade, a large number of studies on treatment with mesenchymal stem cells(MSCs) have been conducted. Most clinical reports, especially those from dermatologists, have described bone marrow-adherent cells (BMACs) as MSCs. BMACs are generally separated using Dexter's method or the Percoll gradient method, and are cultured with human serum, fetal bovine serum and cytokines to increase the number of stem cells. Subsequently, they are transplanted to patients' bones, articular cartilage or tendious tissue. During the last 10 years it has been reported that few MSCs can be harvested from bone marrow cells ; for example, only four MSCs were obtained from 10^6-10^7 bone marrow cells. Moreover, unsuccessful cases of BMAC transplantation have been reported recently. The failure in these cases was attributed to the methods of culture and sampling or a lack of chemotactic factors, but the issue of whether real MSCs were transplanted was given little attention. There have been no stu … More dies of whether the number of MSCs increases in BMAC cultures and the heterogeneity of BMACs has not yet been analyzed by examining cell-surface markers. Therefore, clinicians might have previously transplanted many more fibroblasts or other cells than actual stem cells. Cultured bore marrow cells (BMACs) have been commonly used in bone and cartilage regeneration therapy. Here we isolated mesenchymal stem cells (MSC) from BMACs by fluorescence activated cell sorter (FACS) directly according to cell surface maker patterns. This MSC population had a high potential to differentiate into osteoblasts, chondrocytes and lipocytes, while the residual cells in BMACs (non-MSC population) differentiate into only two lineages, osteoblasts and lipocytes. Generally, homogeneous chondrogenic defferentiation never happens when cells are not cultured through pellet cultures. However, purified MSCs could produce cartilage-like matrix through monolayer dish culture. The percentage of these multipotential cells was less than 5% in cultured BMACs. MSCs proliferated up to 17-fold in 3-4 weeks after separation from floating cells and did not increase thereafter. Based on our results, when effective tissue repair of the cartilage is required, we must consider the way on their effective use of isolated MSCs using FACS. Less