Involvement of prostaglandins from rheumatoid synovium in inhibition of articular cartilage metabolism.

Short term incubations of articular cartilage in media from cultures of rheumatoid synovial tissue result in marked inhibition of 3H-glycine and Na235SO4 incorporation into trichloroacetic acid (TCA) insoluble macromolecules by the cartilage segments with little effect on degradation of prelabeled cartilage matrix. This inhibition is time dependent and not observed in cartilage segments incubated in media derived from rheumatoid synovia cultured in the presence of indomethacin (a specific inhibitor of prostaglandin synthesis). In addition, no indomethacin-sensitive cartilage inhibitory activity was detectable in media from cultures of normal synovia. The ether solubility of the majority of the inhibitory activity and the indomethacin sensitivity suggest that the inhibitor(s) are prostaglandins.