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

Objective. To determine whether tenascin is present in normal and dise ased human cartilage. Methods. Immunohistochemical and biochemical ass ays with a monoclonal antibody against all tenascin isoforms (BC-4) we re used. Results. Cartilage samples from osteoarthritis and rheumatoid arthritis patients contained increased amounts of tenascin compared w ith the levels in normal cartilage. Human fetal cartilage was also fou nd to contain tenascin. In normal cartilage explants treated with inte rleukin-1 beta, tenascin was present in pericellular areas of all laye rs. Immunolocalization studies revealed that tenascin was most abundan t in the superficial layers of osteoarthritic cartilage. Western blot analysis performed from dissociative extracts of diseased cartilage co nfirmed the presence of subunits of the native molecule. Conclusion. T enascin is increased in arthritic cartilage and is weakly expressed in normal cartilage.