Objective: To investigate the effects of Guizhi Fuzitang on mitogen-activated protein kinase (MAPK) signaling pathway in the synovial tissue of rats with collagen-induced arthritis (CIA).Method: The 60 SD rats were randomly divided into normal group

model group

Guizhi Fuzitang group (1.5

4.5

13.5 g·kg-1) and methotrexate group. The rats were injected subcutaneously with chicken typeⅡcollagen (CCⅡ) through tail root to establish CIA model. Since the 14th day after modeling

the arthritic index of all groups at different time points were observed and measured. The expressions of JNK

ERK and p38 proteins in MAPK signal transduction pathway as well as the expression of corresponding phosphorylated proteins p-JNK

p-ERK and p-p38 were detected by western blot.Result: The swelling degree and arthritis index of the CIA rats were higher than the normal group at 7 th

14 th

21 th

28 th

35 th

42 th time

and were significantly reduced at d14 after being given Guizhi Fuzitang. Guizhi Fuzitang can obviously alleviate the synovial hyperplasia and the infiltration of inflammatory cell

and reduce the inflammatory cells. Compared with the normal group (p-JNK

p-ERK

p-p38)

the protein expression level (p-JNK

p-ERK

p-p38) of the CIA group significantly increased

with significant differences between the two groups (P<0.01). Compared with the model group

the protein expression level (p-JNK

p-ERK

p-p38) of the methotrexate group significantly decreased

with significant differences between the two groups (P<0.01). Compared with the model group

CIA rats showed significantly lower protein expression levels of p-JNK

p-ERK

p-p38 in a dose-dependent manner.Conclusion: Guizhi Fuzitang could inhibit the activation of MAPK signal transduction pathway to alleviate the symptoms of inflammation in CIA rats.