Catabolin/interleukin-1 regulation of cartilage and chondrocyte metabolism.

Catabolin/interleukin-1 effects on metabolism were studied in bovine nasal cartilage organ culture and articular chondrocyte cell culture. Keratan sulfate (KS) and hyaluronic acid (HA) were determined by an ELISA; prostaglandin E2 by RIA, sulfated glycosaminoglycan using dimethylmethylene blue and proliferation by incorporation of tritiated thymidine. Gel filtration of untreated 4-day organ culture media indicated that large sulfated and KS-containing proteoglycans were released and eluted in the void volume. Catabolin/interleukin-1 increased release of sulfated glycosaminoglycans and these were of lower molecular weight with an altered distribution of KS. Catabolin/interleukin-1 treatment of chondrocytes caused a decrease in KS production and proliferation but an increase in HA and in prostaglanding E2 production. Alterations of the chondrocyte metabolism by catabolin/interleukin-1 causing proteoglycan matrix degradation and modulation of chondrocyte glycosaminoglycan biosynthesis and proliferation may play a role in cartilage erosion and failure to repair in arthritic diseases.