Effects of triptolide from Radix Tripterygium wilfordii (Leigongteng) on cartilage cytokines and transcription factor NF-κB: a study on induced arthritis in rats

BACKGROUND Triptolide, an active compound of Radix Tripterygium wilfordii, is immunosuppressive, cartilage protective and anti-inflammatory both in human and animal studies of various inflammatory and autoimmune diseases, including rheumatoid arthritis, but its therapeutic mechanism remains unclear. The aim of this study is to investigate the effects of triptolide on cartilage cytokines in the CIA model. METHODS Sprague Dawley rats were immunized with type II collagen and orally administered with triptolide. The arthritic scores and incidence changes of the rats were observed. The expression of TNF-alpha, IL-6, COX-2 and NF-kappaB in paw cartilage was studied with immunohistochemical staining. RESULTS Triptolide, at both high and low doses, significantly lowered the arthritic scores, delayed the onset of arthritis and lowered the arthritis incidence. Triptolide treatment at both high and low doses lowered the expression of TNF-alpha, IL-6, COX-2 and NF-kappaB in paw cartilage in arthritic rats. CONCLUSION Triptolide lowers the arthritic scores, delays the onset of collagen induced arthritis and reduces the expressions of TNF-alpha, IL-6, NF-kappaB and COX-2 in paw cartilage in arthritic rats.