TENASCIN DISTRIBUTION IN ARTICULAR-CARTILAGE FROM NORMAL SUBJECTS AND FROM PATIENTS WITH OSTEOARTHRITIS AND RHEUMATOID-ARTHRITIS

Objective. To determine whether tenascin is present in normal and diseased human cartilage. Methods. Immunohistochemical and biochemical assays with a monoclonal antibody against all tenascin isoforms (BC-4) were used. Results. Cartilage samples from osteoarthritis and rheumatoid arthritis patients contained increased amounts of tenascin compared with the levels in normal cartilage. Human fetal cartilage was also found to contain tenascin. In normal cartilage explants treated with interleukin-1 beta, tenascin was present in pericellular areas of all layers. Immunolocalization studies revealed that tenascin was most abundant in the superficial layers of osteoarthritic cartilage. Western blot analysis performed from dissociative extracts of diseased cartilage confirmed the presence of subunits of the native molecule. Conclusion. Tenascin is increased in arthritic cartilage and is weakly expressed in normal cartilage.