Expression Of Stromal Cell-derived Factor-1 After Articular Cartilage Injury And Its Significance

OBJECTIVE:To establish Rabbit BMSC isolation, purified, cultured, amplified, labeled method in vitro.METHODS:BMSCs were isolated by combining density gradient centrifugation with plastic adherence, and then labeled by BrdU, at the same time, by the MTT observe the activity the cells labeled.MAIN OUTCOME MEASURES:Trypan blue demonstrated cytoactive after the density gradient centrifugation; Morphological observations were performed with phase contrast microscope; growth curves of the cells were drawn by cytometry method; cell phenotype and generation cycle were detected by flow cytometry.RESULTS:Results Trypan blue exclusion demonstrated>99% viability; Higher purity of Rabbit BMSCs could be achieved by the density gradient centrifugation. The positive expression rates of cell phenotypes were various as followings respectively:CD90,99.24%; CD45,0.03%; CD34,1.37%. The growth curve of Rabbit BMSCs was "S" shape. The Rabbit BMSCs nucleus show green fluor under fluorescence microscope after labeled by the BrdU. It showed that no significant toxicity on cells after BrdU labeling. The most appropriate time for BrdU labeling Rabbit BMSCs is 48 hours, the most appropriate concentration is 10μg/mL.CONCLUSION:Higher purity of Rabbit BMSCs can be isolated and cultured by combining density gradient centrifugation with adherence. Labeling Rabbit BMSCs with BrdU is a simple efficient labeled method, and the Labeling rate is high and cytotoxicity is little. OBJECTIVE:To investigate the possible mechanism of chemoattracting MSCs to the focal osteochondral lesions, and to afford the theoretical and experimental proof to regulate and control of MSCs unidirectional migrate to the local lesions of Articular cartilage injury. Methods:Models with injury of Articular cartilage injury were induced in rabbit. Focal osteochondral lesions were collected 2,5,7,10,14 and 28day after injury. Methods ELISA to detect the expression of SDF-1 protein and migration assay to observe by counting migrated cells and by calculating the mobility to show the difference of MSCs migration under the conditions with or without the existence of SDF-1, which was extracted from the Articular cartilage tissues and cells by lysis buffer. BrdU-labeled MSCs were injected intravenously into rabbits of control group, experimental group.Anti-CXC chemokine receptor 4 (Anti-CXCR4) antibodies were used for blocking studiesResults:SDF-1 expression increases in the early phase Articular cartilage injury and remains at a high level for two weeks, which may play an important role in chemoattracting MSCs to the focal osteochondral lesions. SDF-1 is one of chemotaxis factors which attract MSCs to home to focal osteochondral lesions. Higher expression of SDF-1 is the possible mechasism of bone marrow stem cells homing to focal osteochondral lesions.Conclusion:Through regulating the pivot of SDF-1/CXCR4, which may be responsible for the chemotaxis and congregation of MSCs, This phenomenon will be significant in the therapeutical research of acute Articular cartilage injury.