Fig. 1

GTS-21 ameliorated inflammation in collagen-induced arthritis (CIA) mice. a The CIA model in DBA/1 mice was successfully established. GTS-21 decreased the redness and swelling of joints in CIA mice. b The arthritis score index was used to assess the severity of arthritis. GTS-21–treated CIA mice showed a dramatic decrease in arthritis scores compared with those in mice in the model group and vagotomy group. c and d The score of inflammatory cell infiltration (grade 0–4), synovial hyperplasia (grade 0–3), and tartrate-resistant acid phosphatase–positive (TRAP⁺) cells in the ankle (c) and knee (d). e and f GTS-21 decreased the infiltration of inflammatory cells and synovial proliferation in the ankle (e, 40×) and knee (f, 40×) in CIA mice. g and h GTS-21 decreased the infiltration of osteoclasts in the ankle (g, 40×) and knee (h, 40×) in CIA mice (the arrows point to TRAP⁺ cells). Data are expressed as the mean ± standard deviation (n = 8). *P <0.05 versus the model group; ^#P <0.05 versus the vagotomy group