Anti-inflammatory Effect and Mechanism of Duhuo Jishengtang on Rheumatoid Arthritis Rats Based on TLR2/p38 MAPK/NF-κB Signaling Pathway / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo explore the anti-inflammatory effect of Duhuo Jishengtang （DHJST） on collagen-induced arthritis （CIA） model rats and its effect on the Toll-like receptor 2 （TLR2）/p38 mitogen-activated protein kinase （MAPK）/nuclear factor-κB （NF-κB） signaling pathway. MethodForty-eight male SD rats were randomly divided into the following six groups （n=8）： normal group， model group， methotrexate （MTX） group， low-dose DHJST （DHJST-L） group， medium-dose DHJST （DHJST-M） group， and high-dose DHJST （DHJST-H） group. The CIA model was established by injecting bovine type Ⅱ collagen into the rat tail root with the collagen antibody induction method. After model induction， rats were treated with drugs by gavage. The rats in the MTX group received MTX at 2.0 mg·kg-1， three times a week， and those in the DHJST groups received DHJST at 3.8， 7.6， 15.2 g·kg-1·d-1 for 28 days. The rats in the normal group and the model group were given the same dose of normal saline. The weight of the rats was recorded， and the paw swelling degree was observed. The arthritis index and immune organ index were measured， and the changes in the microcirculation indexes of the rats were detected with a microcirculation detector. Hematoxylin-eosin （HE） staining was used to detect the pathological morphologic changes in rat synovial tissues and the apoptosis rate of synovial cells was detected by flow cytometry to determine the therapeutic effect of DHJST on rheumatoid arthritis. Enzyme-linked immunosorbent assay （ELISA） was used to detect the changes in serum levels of tumor necrosis factor-α （TNF-α）， interleukin （IL）-1β， IL-17A， and interferon-γ （IFN-γ）. The protein expression of TLR2， NF-κB p65， phosphorylated NF-κB p65 （p-NF-κB p65）， p38 MAPK， and p-p38 MAPK was detected by Western blot. ResultCompared with the normal group， the model group showed reduced body weight （P<0.01）， increased paw swelling degree， arthritis index， and immune organ index （P<0.01）， increased comprehensive microvascular score and vascular resistance （P<0.01）， significant hyperplasia of synovial tissues and massive infiltration of inflammatory cells as revealed by pathological sections， and up-regulated expression levels of TNF-α， IL-1β， IL-17A， and IFN-γ in serum， and TLR2， p-NF-κB p65/NF-κB p65 and p-p38 MAPK/p38 MAPK in synovial tissues （P<0.01）. Compared with the model group， the DHJST groups showed increased body weight of rats （P<0.01）， decreased paw swelling degree， arthritis index， and immune organ index （P<0.05， P<0.01）， reduced comprehensive microvascular score and vascular resistance （P<0.05， P<0.01）， improved synovial histopathological injury， increased apoptosis rate of synovial cells （P<0.01）， and down-regulated levels of TNF-α， IL-1β， IL-17A， and IFN-γ in serum （P<0.05， P<0.01） and TLR2， p-NF-κB p65/NF-κB p65 and p-p38 MAPK/p38 MAPK in synovial tissues （P<0.05， P<0.01）. ConclusionDHJST may alleviate the inflammatory reaction in CIA rats by regulating the TLR2/p38 MAPK/NF-κB signaling pathway， thus exerting its anti-rheumatoid arthritis effect.