To investigate the effects of Platycodon grandiflorum extract（PGE）on the proliferation and metastasis of fibroblast-like synovial cells in rheumatoid arthritis（RA）and its mechanism of action.

Fibroblast-like synovial cells MH7A were divided into control group, PGE-L group（25 mg·L^-1 PGE）, PGE-M group（50 mg·L^-1 PGE）, PGE-H group（100 mg·L^-1 PGE）, PGE + angiotensin（Ang）Ⅱ group（100 mg·L^-1 PGE + 100 nmol·L^-1 Ras homologous gene family member A（RhoA）/Rho kinase（ROCK）pathway activator AngⅡ）, and treated accordingly. Cell proliferation, apoptosis, migration and invasion were detected by CCK-8 method, flow cytometry and Transwell, respectively.The expression levels of related proteins were detected by Western blot, and the RhoA activity in cells was detected by GST-pull down method.

Compared with the control group, absorbance value（24, 48 and 72 h after PGE treatment）,the number of migrating and invading cells, the expression of cyclin D1, matrix metalloproteinase（MMP）-2, MMP-9,ROCK1 and ROCK2 proteins, and the activity of RhoA were significantly reduced, and p21 protein expression and the apoptosis rate were increased in PGE-L group, PGE-M group, and PGE-H group, and the higher the concentration of PGE,the more obvious the corresponding trend was（P<0.05）. Compared with the PGE-H group, the absorbance value（24, 48,72 h after PGE treatment）, the number of migratory and invasive cells, the expression of cyclin D1, MMP-2, MMP-9, ROCK1,ROCK2 protein and RhoA activity were increased, amd p21 protein expression and apoptosis rate decreased in PGE + Ang Ⅱgroup（P<0.05）.

PGE can inhibit the proliferation and metastasis of MH7A cells, which may be related to the inhibition of RhoA/ROCK pathway.