Objectives :The object of this study is to observe the favorable anti-arthritic effects of Imyo-san(Èrmiào-sǎn)(IMS), that has been traditionally used in Korean medicine to treat rheumatoid arthritis, on Freund’s complete adjuvant(FCA)-induced arthritic Wistar rats.
Methods :Rheumatoid arthritis was induced by intradermal injection of FCA(10 mg in 1 ml paraffin oil 0.1 ml/rats). Each of 8 rats showing regular ankle thicknesses, per group selected after 14 days after FCA treatment to confirm the induction of rheumatoid arthritis. 300, 150 or 750 mg/kg of IMS were orally administered once a day for 14 days from 14 days after FCA treatments. Dexamethasone was intraperitoneally administered 15 mg/kg, once a day for 14 days from 14 days after FCA treatments. Experimental animals were sacrificed after 14 days of continuous oral treatment of IMS or intraperitoneal administration of dexamethasone, and changes on the body weight, knee circumferences, gross arthritis score, inflammatory tissue prostaglandin(PG) E2 level sand cartilage collagen, glucosaminoglycans compositions–chondroitin sulphate, heparan sulphate and hyaluronic acid in the present study.
Results :As results of FCA treatment, classic rheumatoid arthritis featuring dramatical decreases on the body weight, cartilage collagen contents and bone glucosaminoglycans - chondroitin sulphate, heparan sulphate and hyaluronic acid contents, with increases on the knee circumferences, gross arthritis scores and inflammatory tissue PGE2 levels. However, these changes from FCA-induced rheumatoid arthritis were clearly reduced by treatment of dexamethasone and both two different dosages of IMS, 300 and 150 mg/kg in the present study. Although FCA-induced arthritis were more favorably inhibited by treatment of dexamethasone 15 mg/kg as compared with IMS 300 mg/kg, marked decreases of body weights were detected in dexamethasone 15 mg/kg treated rats.
Conclusions :The results obtained in this study suggest that over 150 mg/kg of IMS showed favorable anti-arthritic effects on the FCA-induced arthritis mediated by suppression of PGE2. However, detailed mechanism studies should be carried out in future with the screening of the biological active compounds in this herb. Although FCA-induced arthritis were more favorably inhibited by treatment of dexamethasone 15 mg/kg as compared with IMS 300 mg/kg, marked decreases of body weights were detected in dexamethasone 15 mg/kg treated rats, in the present study.