Cartilage-associated collagenolytic activity in rabbits with antigen-induced chronic synovitis.

Rabbit articular cartilage fragments from knees with normal and antigen-induced chronic synovitis were assayed for active and latent collagenolytic activity. Significant levels of latent collagenolytic activity, as measured by hydroxyproline release, were associated with cartilage from chronic synovitis knee cartilage but not from normal knee cartilage. Neither normal nor chornic synovitis knee cartilage contained demonstrable levels of spontaneously active cartilage-associated collagenolytic activity. Cartilage-associated latent collagenolytic activity was demonstrated only after activation with either trypsin or p-aminophenylmercuric acetate and was inhibited by EDTA (10(-2)M) and 1,10-phenanthroline (10(-3) M). Cartilage-associated latent collagenolytic activity was demonstrated after incubation of activated cartilage at 37 degrees C but not 4 degrees C. The activity could not be removed or diminished by extensive prewashing of these cartilage fragments. Treatment of rabbits undergoing development of antigen-induced chronic synovitis, with methylprednisolone (1 mg/kg/day), significantly suppressed the level of cartilage-associated collagenolytic activity in antigen-challenged knees. The measurement of cartilage-associated collagenolytic activity may be useful for the evaluation of potential antirheumatic drugs.