Angelica sinensis polysaccharide inhibits inflammation of collagen-induced arthritis rat fibroblast-like synoviocytes by inhibiting JAK2/STAT3 and MAPK signaling

A. sinensis polysaccharide (ASP), one of the effective components of A. sinensis, has been used to treat inflammatory diseases in China. However, its effect on rheumatoid arthritis (RA) is unknown. The purpose of this study was to explore the anti-inflammatory effects and mechanisms of ASP on RA using a rat model of collagen-induced arthritis (CIA). For evaluation of the therapeutic effects of ASP in vitro, the CIA model was used. Our study showed that ASP (100 and 200 μg/mL) dose-dependently inhibited tumor necrosis factor (TNF)-α-induced (10 ng/mL) proliferation, migration, and invasion of fibroblast-like synovial (FLS) cells, promoted apoptosis, and arrested the cell cycle in G0/G1 phase (P < 0.05). In vivo, ASP increased body weight in CIA rats while decreasing paw swelling, arthritis score, and synovial tissue proliferation (P < 0.05). ASP also reduced the expression of pro-inflammatory cytokines (interleukin (IL) −6, IL-1β, inducible nitric oxide synthetase (iNOS), matrix metalloproteinase (MMP)-1 and MMP-3) (P < 0.05). ASP inhibited the phosphorylation of JAK2/STAT3 and MAPK signaling pathway components (P < 0.05) induced by TNF-α in CIA-FLS cells. Using JAK and p38 inhibitors, we found that JAK2/STAT3 might be an upstream pathway of MAPK. In conclusion, our study investigated the therapeutic effects of ASP in RA in vitro and in vivo. Our research suggests that ASP can inhibit the invasiveness and secretion of inflammatory cytokines of FLS cells in CIA rats via JAK2/STAT3 and MAPK signaling. Elucidation of the underlying mechanism will provide a theoretical basis for clinical application of ASP.