Cyclooxygenase activity in chondrocytes from osteoarthritic and healthy cartilage

Objectives. To compare prostaglandin production and cyclooxygenase activity in high-density primary cultures of chondrocytes from patients with osteoa rthritis and from healthy controls. Methods. Chondrocytes harvested from op erative specimens obtained during hip or knee arthroplasty were cultured at a very high density for 48 h. Cyclooxygenase activity was evaluated based on prostaglandin E-2 levels (radioimmunological assay) after addition of ar achidonic acid. The chondrocytes were cultured with and without IL-1 beta a nd TNF alpha. Results. Prostaglandin E-2 production and cyclooxygenase acti vity were significantly higher in cultures of chondrocytes from osteoarthri tic than from healthy joints. Adding IL-1 beta to the osteoarthritic chondr ocyte cultures further increased the high cyclooxygenase activity, whereas adding TNF alpha alone had no effect. Conclusion. Cultured chondrocytes fro m osteoarthritic joints showed increased prostaglandin E-2 production and c yclooxygenase activity.