ABSTRACT
The chondrocyte in articular cartilage is responsible for the homeostasis of the surrounding intercellular matrix. In order to understand the changes in the bioactivity of the cartilage cell in rheumatoid arthritis, this chapter discusses the immune response and the immune processes and cytokines involved, in the synovial membrane in this disease; the effects of these cytokines on the chondrocyte; and the role of the chondrocyte in the production of cytokines. It describes the effects of cytokines on cartilage expiants and in in vivo models of joint inflammation; and presents the observations made in articular cartilage from patients with rheumatoid arthritis. Living chondrocytes secrete the enzymes. IL-1, for instance, has no capacity to stimulate glycosaminoglycan (GAG) release from or inhibit GAG synthesis by dead cartilage and inhibitors of protein synthesis, or suppress cytokine-stimulated cartilage matrix resorption. Proteoglycan synthesis is altered in vivo in rheumatoid articular cartilage.
