MMP3 and rheumatoid arthritis: Previous studies found that moxibustion treatment can relieve morning stiffness, joint swelling, pain and other clinical symptoms of RA patients and improve their quality of life.[9] Moxibustion could not only increase the effect on clinical symptoms, but also decrease the serum level of IL-1, TNF-α, MMP-1, and MMP-3, which were serological markers related to bone and cartilage metabolism of RA.[11] Therefore, we decided to adopt moxibustion as an intervention in this study.