ABSTRACT:

Purpose: To investigate the anti-arthritic activity of the water extract of Rhizoma Arisaematis (WERA) using collagen II (CII)-induced arthritis (CIA) rat model.
Methods: CIA was induced in male Sprague-Dawley rat by intra-dermal injection of bovine collagen type II (C II) in Freund’s complete adjuvant (cFA). The rats were treated daily for 21 consecutive days with WERA at doses of 100, 200, and 400 mg/kg. Methotrexate (MTX) was used as positive control, and administered at a dose of 3 mg/kg intraperitoneally in two-weekly cycles for 3 weeks. Severity of arthritis was evaluated by arthritic scores, including paw swelling, arthritic score, body weight, thymus index and spleen index. The levels of IL-1β, IL-6, IL-10 and TNF-α in serum were also measured.
Results: The results revealed that WERA significantly inhibited paw edema (p-value < 0.01), decreased arthritis scores (p-value < 0.01) and spleen index (p-value < 0.05), and alleviated the weight loss of CIA rats. Furthermore, the pro-inflammatory cytokines of TNF-α (19.3%, 60.5% and 73.9%, respectively), IL- 1β (7.9%, 41.1% and 52.7%, respectively) and IL-6 (26.6%, 48.0% and 72.2%, respectively) were remarkably attenuated in serum of all WERA-treated rats, however, IL-10 (72.4% and 39.1%, respectively) was markedly increased at doses of 200 and 400 mg/kg of WERA.
Conclusion: The results demonstrate that WERA exerts therapeutic effects in collagen—induced arthritis of rats by decreasing the levels of TNF-α, IL-1β, IL-6 and IL-10 in serum, and therefore may be an effective candidate drug for the treatment of human rheumatoid arthritis.