Extracts of Arisaema rhizomatum C.E.C. Fischer attenuate inflammatory response on collagen-induced arthritis in BALB/c mice

Abstract

Arisaema rhizomatum C.E.C. Fischer (ARCF), called as "Xuelijian", a local herb just growing in China, has been used as a traditional ethnic Chinese medicine for long because of its remarkable activity to alleviate pain and inflammation for patients suffering from rheumatism among the people with weak side-effect. However, rare study on the anti-arthritic activity of ARCF has been reported in vivo. The aim of this study is to investigate the protective effect of the herb on collagen-induced arthritis in mice and explore the potential immunological mechanisms. CIA was induced in male BALB/c mice by been subcutaneously injected type II bovine collagen (CII) for twice. The combined MeOH extract (ME) of ARCF rhizome was successively partitioned into four fractions with petroleum ether (PE), ethyl acetate (EE), n-butyl alcohol (n-BE) and water (WE). After the second collagen immunization, mice were administered orally with different doses of ME, EE and n-BE (ME 130, 261, 522 mg kg(-1); EE 10.2, 20.4, 40.8 mg kg(-1); n-BE 52, 104, 208 mg kg(-1)) every other day for 3 weeks. The progression of edema of paws and knee joints was inspected by using a vernier calliper every 3 days from the 10th day after the first injection to the end of the experiment. The spleen index was measured and the knee joint destruction was observed by pathological sections. Levels of inflammatory cytokines including tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), interleukin-6 (IL-6), interleukin-33 (IL-33 or IL-1F11) and rheumatoid factor (RF) in serum were measured by ELISA. Administration of ME, EE and n-BE significantly suppressed paws and joints swelling and reduced the spleen indexes. Pathological examination demonstrated that ARCF effectively protected anklebone and cartilage from being eroded versus vehicle-treated mice. Moreover, the serum levels of inflammatory cytokines TNF-α, IL-1β, IL-6, IL-33 and RF were markedly lowered in ARCF treated groups compared with the control group (p<0.05). Our studies demonstrate that administration of ARCF is obviously suppressed the progression of CIA. The anti-arthritic effectiveness of ARCF will make the herb a strong candidate for further clinical trials on RA patients.