Periplosides Extract from Cortex periplocae Improve Collagen Antibody-Induced Arthritis by Regulating Macrophage Polarization

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease characterized primarily by the synovial infiltration of inflammatory cells. Macrophage infiltration in the joint synovium is one of the early hallmarks of RA disease activity. Cortex periplocae, which has been widely employed in traditional Chinese medicine (TCM) to alleviate RA, harbors a bioactive compound known as Periploca sepium periplosides (PePs). In this study, collagen antibody-induced arthritis (CAIA) was established in mice through the administration of collagen antibodies and lipopolysaccharide (LPS), followed by treatment with PePs. The therapeutic effects of PePs were evaluated by measuring paw thickness, clinical arthritis scores, and histological changes in joint tissues. Flow cytometry and qRT-PCR were used to assess macrophage polarization in vivo and in vitro. The findings indicate that PePs effectively attenuated CAIA by suppressing the polarization of RAW264.7 cells towards the M1 phenotype while promoting their polarization towards the M2 phenotype. These results provide valuable insights into the scientific significance of PePs as a potential therapeutic agent for RA.