Effect of Acupuncture Stimulation on Improving the Immunity of Synovial Tissue in Rheumatoid Joints via MAPK Pathway

Purpose : Acupuncture treatment of rheumatoid arthritis (RA) has a long history and has been widely recognized in the medical community. However, its mechanism of action still is rarely uncovered. In the present study, the effects of acupuncture on the immune function and MAPK pathway in synovial tissue of rats with RA were investigated; it aimed to explore the effect and mechanism of acupuncture on alleviating RA. Methods: Rats were randomly divided into control, model and acupuncture groups, 15 rats each group, and RA rat model was induced via bovine type II collagen in complete Freund's adjuvant. The acupuncture group received "Zusanli" and "Shenshu" warm acupuncture treatment on the first day after modeling, acupuncture stimulation once a day for 21 days. The rat weight and degree of joint swelling were recorded and calculated. The ankle joint histopathology was observed by H&E staining. Serum inflammatory cytokines were detected using ELISA. An automatic biochemical analyzer was used to test serum IgG, IgM and IgA levels. Transcription factors T-bet, GATA3, RORγT, Foxp3 mRNA were monitored through RT-qPCR technology. Further, the expression of key targets of MAPK signal or phosphorylation in synovial tissue were determined using Western blotting. Results: Acupuncture relieved the joint swelling and weight loss of RA rats, ameliorated the pathological damage of the ankle joint, significantly increased the serum IgG, IgM, IgA and T-bet, and Foxp3 levels, and reduced the levels of IL-1β, IL-6, TNF-α, GATA3, and RORγT; down-regulated synovial tissue p-p38MAPK, p-JNK, and p-ERK1/2 levels and protein phosphorylation ratio ( P <0.05). Conclusion: Acupuncture stimulation can improve the joint damage and promote the immune function of RA rats, possibly via blocking the expression of MAPK pathway in synovial tissue. This study provides a scientific and promising reference for acupuncture further in the clinical strategy of RA.