Guizhi-Shaoyao-Zhimu decoction attenuates bone erosion in rats that have collagen-induced arthritis via modulating NF‐κB signalling to suppress osteoclastogenesis

Abstract

Context

Guizhi-Shaoyao-Zhimu decoction (GSZD) is commonly used to treat rheumatoid arthritis (RA), but its mechanism is unclear.

Objective

To investigate the effect of GSZD on bone erosion in type II collagen (CII)-induced arthritis (CIA) in rats and to identify the underlying mechanism.

Materials and methods

The CIA model was prepared in male Wistar rats by two subcutaneous injections of CII, 1 mg/mL. Fifty CIA rats were randomized equally into the control group given saline daily, the positive group given saline daily and methotrexate 0.75 mg/kg once a week, and three GSZD-treated groups gavaged daily with 800, 1600 and 3200 mg/kg of GSZD for 21 days. GSZD effects were assessed by paw volume, arthritic severity index and histopathology. Cytokine levels were determined by ELISA. The effects of GSZD on RAW264.7 cells were evaluated by receptor activator of NF-κB ligand (RANKL)-induced osteoclastogenesis and bone resorption assay. Expression of IκB-α and p65 was measured by Western blotting. Major components of GSZD were identified by HPLC.

Results

Arthritis index score, paw volume and bone destruction score showed that GSZD improved inflammatory symptoms and reduced joint tissue erosion (p < 0.01). GSZD decreased RANKL, and the number of osteoclasts (OCs) in joint tissues (p < 0.01) and increased osteoprotegerin levels (p < 0.01). GSZD inhibited RANKL-induced RAW264.7 differentiation and reduced bone resorption by OCs. GSZD upregulated IκB (p < 0.01) and p65 (p < 0.01) in the cytoplasm and downregulated p65 (p < 0.01) in the cell nucleus.

Conclusions

Guizhi-Shaoyao-Zhimu decoction has an anti-RA effect, suggesting its possible use as a supplement and alternative drug therapy for RA.

Keywords:

• Rheumatoid arthritis
• osteoclast
• RANKL
• osteoprotegerin

Disclosure statement

The authors declare that there are no conflicts of interest.

Additional information

Funding

This work was supported by the National Science and Technology Major Project of the Ministry of Science and Technology of China [No. 2018ZX09721004-009-002], Sichuan Science and Technology Program [No. 2019JDRC0074] and Xinglin Scholar Discipline Promotion Talent Program of Chengdu University of Traditional Chinese Medicine [No. BSH2018006].