Mechanism of Duanteng Yimu Decoction on Expression of MEKK2 in Rheumatoid Arthritis Synovial Fibroblasts and Arthritis in CIA Mice / 中国实验方剂学杂志

ABSTRACT

Objective:Duanteng Yimu decoction(DTYMD)is effective in treatment of rheumatoid arthritis (RA) by relieving joint inflammation and down-regulating some inflammatory factors in a short period of time, but the mechanism is still unclear. We aimed to investigate upstream kinase of mitogen activated protein kinases(MAPK) and define the anti-inflammatory mechanism of DTYMD. Method:Fibroblasts-like synovial cells(FLSs) were divided into blank group, model group (IL-1β), high-dose DTYMD group (1 000 mg·L-1), medium-dose DTYMD group (800 mg·L-1), low-dose DTYMD group (600 mg·L-1) and armour ammonia butterfly(MTX) group (20 μmol·L-1). The protein and mRNA expressions of mitogen-activated protein kinase kinase kinase 2 (MEKK2) were analyzed by real-time fluorescence quantitative PCR(Real-time PCR). Totally 42 male DBA/1J mice were randomly divided into 6 groups, with 7 mice in each group, namely normal group, model group and MTX group (2 mg·kg-1), low-dose DTYMD group (6.25 mg·kg-1), medium-dose DTYMD group (12.5 mg·kg-1), and high-dose DTYMD group (25 mg·kg-1). Except for the normal group, the other five groups were included in collagen-induced arthritis(CIA) model by secondary immunoassay. After administration, the posterior limbs and ankle joints were stained with htoxylin-eosin(HE), and the pathological scores of the joints were evaluated. Result:Compared with the model group, DTYMD inhibited the activity of FLSs in a concentration-dependent manner (P<0.01). Compared with the blank control group, the cell proliferation rate of the model group increased (P<0.01). Compared with the model group, high and middle-dose DTYMD groups could inhibit protein and mRNA expressions of MEKK2 (P<0.01), but there was no significant difference in low-dose group. However, the expression of DTYMD protein in high/medium/low-dose groups was significantly higher than that in blank group (P<0.01), but there was no significant difference in MTX group. Compared with the model group, the expressions of matrix metalloprotease-1 (MMP-1), tumor necrosis factor-α(TNF-α) and interleukin(IL)-6 were negatively regulated in different DTYMD groups(P<0.01), and the expressions of MMP-1, IL-6, TNF-α in the model group were significantly higher than those in the blank group (P<0.05, P<0.01). In the animal experiment, compared with the model group, high/middle-dose DTYMD groups could decrease the degree of joint swelling in CIA mice (P<0.01), but there was no significant difference in the low dose group, and the joint swelling in the model group was significantly higher than that in the blank group (P<0.05). In HE staining of ankle joint of CIA mice, the pathological scores of high/small-dose DTYMD groups were significantly lower those of model group (P<0.05, P<0.01), and the pathological score of model group was higher than that of blank group (P<0.01). Conclusion:DTYMD might down-regulate MEKK2 to negatively regulate inflammatory cytokines IL-6, TNF-α and MMP-1, thereby alleviating the inflammatory response in rheumatoid arthritis.