Effects and mechanisms of total glucosides of paeony on joint damage in rat collagen-induced arthritis

Objective and design: To investigate the therapeutic effects and mechanisms of total glucosides of paeony (TGP), an effective compound of Chinese traditional herbal medicine (CTM), on collagen-induced arthritis (CIA) in rats. Materials: CIA was induced in male Sprague-Dawley rats immunized with chicken type II collagen in Freund's complete adjuvant. Treatment: TGP (25, 50, 100 mg/kg/d) was orally administered to rats from day 14 to 28 after immunization. Methods: Arthritis was evaluated by hind paw swelling, polyarthritis index, and histological examination. Activities of interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF alpha) were determined and the ultrastructure of synoviocytes was observed. The proliferation and the production of vascular epidermal growth factor (VEGF), basic fibroblast growth factor (bFGF), matrix metalloproteinase 1 (MMP-1) and MMP-3 in fibroblast-like synoviocytes (FLS) were detected. Results: The administration of TGP (25, 50, 100 mg/kg, ig x 14 days) suppressed secondary inflammatory reactions and histological changes in CIA model. The ultrastructure of synoviocytes from CIA rats was changed, and the level of IL-1 and TNF alpha produced by macrophage-like synoviocytes (MLS) from CIA rats was elevated. TGP (50, 100 mg/kg, ig x 14 days) inhibited above changes significantly. The MLS supernatants of CIA rats induced more cell proliferation and more production of VEGF, bFGF, MMP-1 and MMP-3 in FLS of CIA than those supernatants from CIA rats treated with TGP (50, 100 mg/kg, ig x 14 days). Conclusion: These results indicate that TGP exerts a suppressive effect on joint destruction in rat CIA. The therapeutic effect of TGP could be associated with its ability to ameliorate the secretion and metabolism of synoviocytes and to inhibit the abnormal proliferation and VEGF, bFGF, MMP-1 and MMP-3 production by FLS.