To further determine the effect of Rspo2 and β-catenin in the development of RA, 12-week-old male C57BL/6 J mice were administrated by intraarticular injection of rmRspo2, Rspo2-Nab, or rmDKK1 once a week for 4 and 8 weeks after AIA. Here, RSPO2 is linked to rheumatoid arthritis.