Inhibition by Retinoic Acid of Collagenase Production in Rheumatoid Synovial Cells

IN rheumatoid arthritis, synovial cells produce many mediators of inflammation in response to stimuli generated within the inflamed joint. Collagenase and prostaglandin E2 are two of these mediators. Both are thought to contribute to the destructive lesions seen in this disease. Collagenase may be the rate-limiting enzyme in the degradation of collagen, which is the principal structural protein of cartilage, tendon, ligaments, and bone1 2 3; and prostaglandin E2 accounts for most of the bone-resorbing activity of rheumatoid tissue.4 Monolayer cultures of rheumatoid synovial cells synthesize and secrete large amounts of collagenase and prostaglandin E2 into culture medium. . . .