TNF and rheumatoid arthritis: The effects of triptolide on cartilage TNF-α, IL-6, COX-2 and NF-κB are unclear; thus the present study investigates the effects of triptolide on cartilage cytokines in the rat CIA model, which is a widely used animal model of inflammatory polyarthritis with similarities to RA, and primarily mediated by an autoimmune response [15-18].