Use of the improved tug-of-war acupuncture for promoting cartilage repair by inducing macrophage polarization in knee osteoarthritis

IntroductionKnee osteoarthritis (KOA) is a type of joint disease causing degenerative changes that are challenging to treat. The improved tug-of-war acupuncture (BHZF) can improve joint pain in KOA. However, the associated mechanism has not been validated.MethodsThe KOA rabbit model was established. After the surgery, the improved BHZF was provided as an intervention, and the animals were euthanized after 2 weeks. Histopathological changes in the synovium and cartilage were observed on hematoxylin & eosin staining and Safranin O-Fast Green staining. Synovial fluid and serum samples were collected to assess the presence of cytokines using the enzyme-linked immunosorbent assay. The expression of M1 macrophage (CD86) and M2 macrophage (ARG1) markers in the cartilage and synovium was detected via immunohistochemistry and immunofluorescence assays.ResultsThe improved BHZF could reduce KOA-related pain and inhibit joint swelling. Further, it significantly maintained the morphology of articular chondrocytes in KOA and reduced the decomposition of the cartilage matrix. Then, it significantly reduced the expression of CD86-positive cells (P < 0.05), and increased the expression of ARG1-positive cells in the cartilage and synovium (P < 0.05). Moreover, it significantly decreased the expression of inflammatory factors interleukin (IL)-1 beta and tumor necrosis factor-alpha in the serum and synovial fluid (P < 0.05), and significantly increased the expression levels of anti-inflammatory cytokines IL-4 and IL-10 (P < 0.05).ConclusionsThe improved BHZF can relieve pain and improve cartilage damage by regulating macrophage polarization in KOA.