Biochemical and pharmacological studies on synovium-cartilage interactions in organ culture

Traumatised normal pig synovium has been cultured with normal pig articular cartilage for 14 days. The breakdown of cartilage collagen and proteoglycan during culture was accompanied by the appearance in the culture medium of collagenase and proteoglycanase respectively which appeared to be derived from the synovium. There was good correlation between culture medium levels of collagenase and cartilage collagen breakdown, but the relationship between synovial proteoglycanase and cartilage proteoglycan breakdown was not so clear-cut. Corticosteroids consistently inhibited breakdown of cartilage collagen but not proteoglycan, and inhibited the production of the proteolytic enzymes. High concentrations of aurothiomalate (10(-3)M) inhibited collagen breakdown and partially reduced culture medium enzyme levels. Non-steroidal antiinflammatory agents such as flurbiprofen and indomethacin had no effect on the breakdown of collagen or proteoglycan and tended to increase culture medium enzyme levels. This culture system may be used to provide further information concerning the action of antirheumatic drugs.