Melittin acupoint injection in attenuating bone erosion in collagen-induced arthritis mice via inhibition of the RANKL/NF-κB signaling pathway

Fenfang Liu; Fen Chen; Le Yang; Fucheng Qiu; Guangen Zhong; Shan Gao; Weizhe Xi; Meilian Lai; Qiting He; Ying Chen; Weiming Chen; Jiping Zhang; Lu Yang

doi:10.21037/qims-23-254

Melittin acupoint injection in attenuating bone erosion in collagen-induced arthritis mice via inhibition of the RANKL/NF-κB signaling pathway

Quant Imaging Med Surg. 2023 Sep 1;13(9):5996-6013. doi: 10.21037/qims-23-254. Epub 2023 Jul 20.

Authors

Fenfang Liu^#¹, Fen Chen^#¹, Le Yang¹, Fucheng Qiu², Guangen Zhong³, Shan Gao¹, Weizhe Xi¹, Meilian Lai¹, Qiting He¹, Ying Chen³, Weiming Chen³, Jiping Zhang^#¹, Lu Yang^#^{1

3}

Affiliations

¹ School of Traditional Chinese Medicine, Southern Medical University, Guangzhou, China.
² Intensive Care Unit, Foshan Hospital of TCM, Foshan, China.
³ Department of Acupuncture and Rehabilitation, Integrated Hospital of Traditional Chinese Medicine, Southern Medical University, Guangzhou, China.

^# Contributed equally.

Abstract

Background: Rheumatoid arthritis (RA) is an autoimmune disease leading to chronic joint inflammation. Bone erosion is the most serious pathological condition of RA and the main cause of joint deformities and disability. Melittin acupoint injection (MAI) is an effective traditional Chinese medicine (TCM) method for RA treatment. This study aimed to investigate the effect of MAI on RA bone erosion and to elucidate the underlying mechanism.

Methods: A collagen-induced arthritis (CIA) mouse model was established as the experimental subject. MAI was administrated once every other day for 28 days to mice with CIA. The effects of MAI on joint diseases were assessed by body weight, arthritis index (AI) score, swollen joint count (SJC) score, and hind paw thickness. Ankle radiological changes were captured by micro-computed tomography (micro-CT) and histological changes were observed by pathological staining. Organ histological changes, spleen index, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and creatinine (Crea) levels of serum were tested to evaluate the toxicity of MAI. Cytokine expression levels were confirmed by enzyme-linked immunosorbent assay (ELISA) to evaluate the immunity of CIA mice.

Results: MAI administration markedly improved the clinical signs of CIA in mice, including hind paw thickness, AI, and the number of swollen paw joints (most of them P<0.05 or even <0.01). According to histopathological analysis, MAI ameliorated inflammatory cell infiltration, synovial hyperplasia, pannus formation, and bone erosion (all P<0.01). Micro-CT and tartrate-resistant acid phosphatase (TRAP) staining (P<0.01) also revealed that MAI could relieve bone erosion via reducing the formation of osteoclasts. Not only could MAI relieve the immunological boost [P<0.05 for the high-dose MAI (HM) group], but also it had no liver or kidney side effects (P>0.05). In addition, it decreased the serum levels of interleukin (IL)-6 and tumor necrosis factor-α (TNF-α) and increased the serum levels of IL-4 and IL-10 (the majority of P<0.05 or even <0.01). Transcriptome sequencing results indicated that MAI affected the expression of osteoclast differentiation pathway genes, which was connected with the receptor activator of the nuclear factor κB ligand/nuclear factor kappa B (RANKL/NF-κB) pathway.

Conclusions: Based on our findings, MAI could suppress joint inflammation and inhibit RANKL/NF-κB-mediated osteoclast differentiation to rescue bone erosion in CIA mice, suggesting that MAI can be a potentially therapeutic substance for RA.

Keywords: Melittin acupoint injection; bone erosion; collagen-induced arthritis; receptor activator of the nuclear factor κB ligand/nuclear factor kappa B (RANKL/NF-κB) signaling pathway.