| The defect and degeneration of articular cartilage are common in orthopedic field. Although artificial prothesis is the main and effective choice, high cost and complication could not be neglected. Repairing the defect of articular cartilage with tissue engineering cartilage succeeded preliminarily, but clinical application was suspended because the transplanted tissue engineering cartilage degenerated as time going. The main reason of the degeneration is that the proliferation and passage ability of chondrocyte is limited. The phenotype and activity of chondrocyte are affected, as the specific extracellular matrix (ECM) components are synthesized decreasedly during passage. There are some reports about application of alginate and growth factors to improve the synthesis of ECM, but there are some shortages, such as short biological half-lives, high price and repeatedly addition. Gene transfer, which means to induce aim gene into eukaryotic cells with special method, has following advantages: 1) the transfected cells are able to express aim gene continuously and effectively that can modulate the growth of themselves and other effective cells and to obtain specific functions. 2) the endogenous aim proteins produced by transfected cells have undergone authentic post-translational modification and therefore have improved potencies to combine with receptors on cells' surface as well as more biological activities. 3) the price of gene transfer is lower than that of purified recombinant proteins. Therefore, it is of great value to induce aim gene which could increase ECM synthesis into cells by employing gene transfer techniques. With these gene modified seed cells, the new gene modified tissue engineering cartilage could be constructed in order to repair the defect and degeneration of articular cartilage.The purposes of present study were to investigate possible reasons of articularcartilage degeneration, and to induce TGF-β1 aim gene into chondrocytes and mesenchymal stem cells respectively. The syntheses of ECM and metalloproteinases (MMPs) as well as their activities were analyzed by PC-PCR, Northern blot, Western blot and Zymography analyses. Based on the construction of gene modified seed cells for tissue engineering cartilage, the mechanism of the changes of ECM after gene transfection were investigated in order to establish experimental basis for future construction and application of gene modified tissue engineering cartilage. Part I The Expressions and Significance of Matrix Metalloproteinase-1,2,3 and their Tissue Inhibitor-1,2 in OsteoarthritisObjective To investigate the relationship between immunohistochemical expression of matrix metalloproteinase (MMPs)-1,2,3/their tissue inhibitor (TIMPs)-1,2 and the degeneration of cartilage in osteoarthritis. Method The histological changes of degenerated cartilages by haematoxyllin-eosin staining and the immunohistochemical expressions of MMPs-1,2,3 and TIMPs-1,2 were studied in 22 osteoarthritis cases. The image analysis revealed the relationship between the expressions of MMP-1,2,3, TIMP-1,2 and the degeneration of cartilage. Results The osteoarthritis cartilage underwent fibroplasia, tearing and thinning. The quantity of chondrocyte decreased. The expressions of MMP-1,3 and TIMP-1 were not observed in normal cartilage, while increased significantly in moderate osteoarthritis and decreased in end-stage osteoarthritis. The expression of TIMP-1 was not paralleled with that of MMP-1,3. Little immunostaining of MMP-2 and TIMP-2 was seen in normal cartilage, while their expressions increased in moderate osteoarthritis and decreased in end-stage osteoarthritis. In end-stage osteoarthritis, the expression of TIMP-2 was stronger than that of MMP-2. Conclusions The abnormal expressions of MMP-1,2,3 and TIMP-1,2, which resulted in degradation disorder of extracellular matrix, could induce degeneration of cartilage. Part II The influence on extarcellular matrix and metalloproteinase-1,2,3 of articu...
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