Moxibustion exhibits an anti-inflammatory effect on rheumatoid arthritis rats by promoting the polarization of M2 macrophage

Abstract Background Rheumatoid arthritis (RA) is a refractory autoimmune disease characterized by chronic synovitis. Moxibustion is a natural therapy that possesses anti-inflammatory bioactivity. However, the anti-inflammatory mechanism of moxibustion for the treatment of RA has not yet been clarified. Macrophage infiltration is a prominent characteristic in the pathological process of RA synovitis. Objective The aim of the present research is to investigate the effect of moxibustion on the polarization of macrophage. Methods The rats' right hind paws were injected with freundʼs complete adjuvant (FCA) to establish the model of RA. Seven days after the injection of FCA, moxibustion therapy was performed on the acupoints of Shenshu (BL23) and Zusanli (ST36) once a day for three weeks. The Immunofluorescence, Western bolt and Elisa were used to analyze the influence of moxibustion on the expression of STAT1/miR-155/SOCS1 signaling pathway and macrophage's marker. Results We observed that moxibustion decreased the thickness of foot pad and arthritis scores. Moxibustion up-regulated the exression of Tim-3, promoted the polarization of macrophages to M2 type and inhibited the polarization of macrophages to M1 type. Treatment with moxibustion decreased the level of interleukin (IL)-23 and increased the level of IL-4, IL-10 and Argininase (Arg)-1. Moreover, moxibustion blocked the activation of STAT1/miR-155/SOCS1 signaling pathway and promoted the polarization of macrophages to M2 type. Furthermore, when Tim-3 was knocked down, the anti-inflammatory effect of moxibustion was reduced and the effect of regulating macrophage polarization was inhibited. Conclusion moxibustion may regulate the expression of related molecules in the STAT1/miR-155/SOCS1 signaling pathway through Tim-3, promote the polarization of macrophages M2, and exhibit anti-inflammatory effects.