ABSTRACT
OBJECTIVE: The adhesion molecule that mediate cell-cell and cell-extracellular matrix adhes.ion provides very important role in growth and differentiation of cells and tissue. VLA integrin is a prototype of adhesion molecule which participate in cell-cell and cell-extracellular matrix interacton, especially for collagen, laminin and fibronectin. The biologic functions of VLA-integrin are very diverse. Cartilage is the target tissue of various arthritides including rheumatoid arthritis and osteoarthritis and the process of homeostasis in cartilage matrix may be very important in preservation of cartilage. Although VLA integrin may participate in the process of cartilage degeneration and repair mechanism, tissue.distribution and exact role of VLA integtin in cartilage was not yet clearly defined. METHODS:Immunohistochemical analysis of VLA-integrin in cryostat section of articular cartilage was conducted using monoclonal antibody and avidin-biotin complex method. Analysis was performed in 10 rheumatoid arthritis specimens, 7 osteoarthritis specimens and 1 normal control. RESULTS: 1) Normal cartilage showed strong and diffuse stain with CD29, CD51 and moderate stain of VLA-5. Staining pattern of VLA-1 and 3 was inconstant and weak in intensity. 2) The intensity of VLA expression in articular cartilage of osteoarthritis was upregulated chiefly in CD29, CD51 and slightly in VLA-5. The positive rate of VLA-1 and 3 was similar to that of normal cartilage though the intensity was increased especially at cluster of chondrocytes. 3) VLA-integrin expression of rheumatoid arthritis cartilage was similar to that of osteoarthritis cartilage. CONCLUSION: VLA integrins functioning as fibronectin receptor such as VLA-5 and alpha, beta1 were upregulated in osteoarthritis and rheumatoid arthritis. Intensity was increased at clusters of chondrocytes. It was able to presume from above findings that VLA molecule has some role in the maintenance and repair of articular cartilage. The regulation of expression by cytokines and growth factors and exact function of VLA molecule in cartilage have to be elucidated.