Anti-inflammatory and anti-arthritic effects of taraxasterol on adjuvant-induced arthritis in rats.

Abstract Ethnopharmacological relevance Taraxasterol was isolated from the traditional Chinese medicinal herb Taraxacum which has been frequently used as a remedy for inflammatory diseases. In the present study, we determined the in vivo anti-arthritic effect of taraxasterol on arthritis induced by Freund's complete adjuvant (FCA) in rats. Materials and methods Rats were immunized with FCA by intradermal injection into the right hind metatarsal footpad, and were orally treated daily with taraxasterol at 2, 4 and 8 mg/kg from day 2–28 after immunization. Paw swelling, arthritis index, body weight, spleen index and thymus index were evaluated. The levels of TNF-α, IL-1β, PGE 2 , OPG and RANKL in sera were measured using ELISA. Histopathological changes in joint tissues were examined using hematoxylin and eosin (H&E). Results Taraxasterol significantly suppressed paw swelling and arthritis index, attenuated body weight loss, decreased the spleen index and thymus index induced by FCA. Furthermore, taraxasterol significantly inhibited the overproduction of serum TNF-α, IL-1β, PGE 2 and RANKL, and increased serum OPG production in FCA-induced rats. Histopathological examination indicated that taraxasterol attenuated synovial hyperplasia, bone and cartilage damage, and inflammatory cell infiltration. Conclusions These results suggest that taraxasterol has the potential protective effect against FCA-induced arthritis in rats.