Effects of leukotriene B4 on interleukin-32, interferon-γ and chemokines in rats with rheumatoid arthritis

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 E2, 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.

Effect of quercetin on E-NTPDase/E-ADA activities and cytokine secretion of complete Freund adjuvant-induced arthritic rats

The effect of quercetin was assessed in rats induced with complete Freund adjuvant (CFA). Arthritis scores, paw oedema, latency, activities of myeloperoxidase (MPO), ectonucleoside triphosphate diphosphohydrolase (E-NTPDase), and ectoadenosine deaminase (E-ADA) in lymphocytes were determined. Furthermore, nucleotide and nucleoside levels as well as the secretion of pro- and anti-inflammatory cytokines were evaluated. Animals were treated with saline and quercetin in doses of 5, 25, and 50 mg/kg for 45 days. The result revealed that quercetin (50 mg/kg) reduced arthritis score and paw oedema, and increased the latency in the thermal hyperalgesia test. Histopathological analysis showed that all the doses of quercetin reduced infiltration of inflammatory cells. MPO activity was increased in the arthritis group; however, quercetin reduced this activity. E-NTPDase activity was increased in lymphocytes of arthritis rats, and treatment with quercetin reversed this increase. However, E-ADA activity was reduced in the arthritis group, and treatment with quercetin modulated the activity of this enzyme in arthritis rat groups. Serum adenosine levels were increased in arthritis, and the levels were lowered with quercetin treatment. Quercetin treatment in arthritis groups decreased the elevated levels of cytokines in the arthritis control group. Thus, quercetin demonstrated an anti-inflammatory effect, and this flavonoid may be a promising natural compound for the treatment of arthritis. SIGNIFICANCE OF THE STUDY: Quercetin may represent a potential therapeutic compound in the treatment of rheumatoid arthritis. Findings from this study indicate that quercetin suppresses swelling and attenuates the underlying inflammatory responses. This is the first report where quercetin was shown to modulate the immune response to arthritis via attenuation of the purinergic system (E-NTPDase and E-ADA activities) and the levels of IFN-gamma and IL-4. Thus, this work is relevant to basic research and may be translated into clinical practice.