Anti-inflammatory activity of different isolated sites of Chloranthus serratus in complete Freund's adjuvant-induced arthritic rats

Chloranthus serratus is a traditional Chinese medicine for treating arthritis and bruises. The aim of the present study was to investigate the anti-arthritic activities and possible associated mechanisms of different isolated sites of Chloranthus serratus (DISC) in adjuvant-induced arthritis (AA) rats. The therapeutic effects of the extracts were assessed through changes in body weights, swelling rates, arthritis indexes (AI) and organ indexes. The levels of nitric oxide (NO), malondialdehyde and superoxide dismutase were determined using one-step method, TBA method and hydroxylamine method, respectively; the levels of TNF-α, IL-1β, IL-6, prostaglandin E(2), macrophage inhibitor factor-1, VEGF, immunoglobulin (Ig) G, IgM and IFN-γ in serum were determined using ELISA. Pathological changes and positive expression of VEGF in the ankle joints were investigated using hematoxylin-eosin staining and immunohistochemical staining, respectively. DISC treatment increased the weight gains and thymus indexes, and decreased the swelling rates, spleen indexes and AI in AA rats. The water isolated site (WA) and ethyl acetate isolated site (EA) significantly reversed complete Freund's adjuvant (CFA)-induced changes in the levels of NO, IL-6, TNF-α, IgG and IFN-γ, while the n-butanol isolated site (NB) only reversed the changes in IL-6 and IgG contents. Some changes in the chloroform isolated site group showed the same trend as those in the model group. The extracts relieved synovial hyperplasia, inflammatory cell infiltration and articular surface defects, and reduced the positive expression rate of VEGF in the synovial tissues of the AA rats to varying degrees. The WA exhibited the most marked effects, followed by the EA and NB, indicating that WA had optimal therapeutic effects on CFA-induced arthritic rats, which may be mediated by the oxidative stress and inhibition of inflammatory factors. C. serratus may serve as a potential candidate for the treatment of rheumatoid arthritis.