Electroacupuncture influences pathological changes of the ankle in rats with rheumatoid arthritis by regulating the HIF-1α/VEGF signaling pathway

ZHANG Yong; LI Chunhua; XIONG Dong

doi:10.3969/j.issn.1002-7386.2024.21.005

Abstract：Objective To explore the effect of electroacupuncture on pathological changes of the ankle in rats with rheumatoid arthritis(RA)by regulating the hypoxia inducible factor 1 alpha(HIF-1α)/vascular endothelial growth factor(VEGF)signaling pathway.Methods A total of 50 Sprague-Dawley(SD)rats were randomly assigned into Sham group(blank control),RA group(RA modeling),electroacupuncture group(RA modeling and intervention of electroacupuncture),and CAY10585 group(RA modeling and intraperitoneal injection of the HIF-1α/VEGF signaling pathway inhibitor),electroacupuncture+CAY 10585 group(RA modeling plus electroacupuncture and intraperitoneal injection of the HIF-1α/VEGF signaling pathway inhibitor),with ten rats per group.After establishing the model,the basic morphology of rats in each group was observed.Rats were sacrificed after 8 weeks.The diameter of rat ankle after treatment was measured.The hematoxylin and eosin(H&E)staining of the rat ankle was performed to observe the overall pathological morphology and grade pathological characteristics of synovial cell proliferation,cell erosion,pannus formation,inflammatory cell infiltration and bone erosion.Enzyme-linked immunosorbent assay(ELISA)was performed to measure serum inflammatory factors tumor necrosis factor-α(TNF-α)and interleukin-6(IL-6).Western blot was performed to detect the protein expressions of cartilage matrix factor type Ⅱ collagen(Collagen Ⅱ),C-terminal peptide(CTX Ⅱ),and type Ⅱcollagen C-precursor peptide(CP Ⅱ)in rat ankle joint tissues.Results Compared with those of the Sham group,rats in the RA group had significantly higher diameter of the ankle,pathological scores of proliferation of synovial cells in the ankle joint,cell erosion,pannus formation,inflammatory cell infiltration and bone erosion,and serum TNF-α and IL-6 levels(P＜0.05),as well as the presences of hyperplasia,interstitial edema,and inflammatory cell infiltration in the synovial epithelial layer of the ankle.The intervention of electroacupuncture significantly reduced the diameter of the ankle joint,pathological scores of the proliferation of synovial cells in the ankle joint,cell erosion,pannus formation,inflammatory cell infiltration and bone erosion,and serum TNF-α and IL-6 levels(P＜0.05),which significantly relieved the pathological morphology of the ankle joint.CAY10585 intervention further aggravated the pathological morphology of RA rats,resulting in a significant increase in osteoclasts,bone erosion,osteolysis,and inflammatory cell infiltration.It significantly enhanced the diameter of the ankle joint,pathological scores of proliferation of synovial cells in the ankle joint,cell erosion,pannus formation,inflammatory cell infiltration and bone erosion,and serum TNF-α and IL-6 levels(P＜0.05).Electroacupuncture intervention reversed CAY 10585-aggravated pathological changes in RA rats,which significantly reduced the diameter of the ankle joint,pathological scores of the proliferation of synovial cells in the ankle joint,cell erosion,pannus formation,inflammatory cell infiltration and bone erosion(P＜0.05).Compared with those of the Sham group,rats in RA group had significantly higher level of CTX Ⅱ in the ankle joint tissue,but lower levels of Collagen Ⅱ and CP Ⅱ(P＜0.05).Electroacupuncture intervention significantly downregulated CTX Ⅱ and upregulated Collagen Ⅱ,CP Ⅱ,HIF-1α and VEGF(P＜0.05).CAY 10585 showed the opposite trend,further upregulating CTX Ⅱ and downregulating Collagen Ⅱ,CP Ⅱ,HIF-1α and VEGF(P＜0.05).Electroacupuncture intervention significantly reversed the cartilage matrix and HIF-1α and VEGF levels in RA rats intervened by CAY10585(P＜0.05).Conclusion Electroacupuncture can improve the pathological manifestations of ankle joints in RA rats,reduce the inflammatory response,and protect cartilage damage by activating the HIF-1α/VEGF signaling pathway.