Fig. 7

Effect of curcumin on collagen-induced arthritis (CIA) is mediated by the cholinergic receptors. Rats were intradermally injected with type II collagen (CII) to induce CIA. Curcumin (Cur, 100 mg/kg) and leflunomide (Lef, 2 mg/kg) were orally given daily 2 weeks. Mecamylamine hydrochloride (Mec, 1 mg/kg) and hexamethonium chloride (Hex, 4 mg/kg) were intraperitoneally injected 10 min before Cur administration. Blood was collected 1 h after treatment on day 28, and the cytokines in serum were assessed by ELISA. a Body weight changes, arthritis index scores, and hind paw swelling. b Representative hematoxylin and eosin (H&E)-stained sections of ankles (original magnification ×100), representative morphology photographs and radiographs of hind paws of CIA rats. Arrows indicate areas of bone destruction. c Histological scores of ankle joint sections. d The levels of cytokines (TNF-α, IL-1β, IL-6, and IL-17A) in serum were assessed by ELISA. Data were shown as means ± S.E.M. for each group (n = 6). ^##p < 0.01 vs. normal group; *p < 0.05, **p < 0.01 vs. model group; ^$p < 0.05, ^$$p < 0.01 vs. Cur group