Effect of melatonin on collagen-induced arthritis in mice

AIM To investigate the effect of melatonin on collagen-induced arthritis (CIA). METHODS The model of mice CIA was prepared and the change of secondary paw-swelling and the mean scores of arthritis were observed. The level of PGE was assayed by spectrophotometer; Meanwhile, 3H-TdR incorporation was used to detect ConA-and LPS-induced splenocytes proliferation and the production of interleukin (IL)-1 and IL-2. Hepatic pathological examination was performed by Hematoxylin-eosin (HE) stain method. RESULTS Treatment of ig melatonin(10,100, 1 000 μg·kg -1) significantly decreased inflammation of the arthritis. The increased ConA-induced splenocytes proliferation ,PGE, IL-1 and IL-2 production in mice CIA were reversed by melatonin. Meanwhile, the pathological examination showed that articulus cartilage degeneration with synovial hyperplasia and inflammatory cells infiltration in CIA mice was suppressed by ig melatonin. CONCLUSION Melatonin has inhibitory effect on mice CIA which may be related to its immunoregulative function.