Xinfeng capsule inhibits cartilage extracellular matrix degradation and inflammation in osteoarthritis by modulating circ_0032131 and miR-502-5p/TRAF2 axis

Abstract Clinical practice has proved that Xinfeng capsule (XFC) can effectively cure osteoarthritis (OA). In our study, we investigated the molecular mechanism and role of XFC in the treatment of OA using network pharmacology and cellular experiments. hsa_circ_0032131 was overexpressed in OA peripheral blood mononuclear cells (PBMCs). Both PBMCs and chondrocytes are cellular members of the inflammatory microenvironment in OA. To investigate the function of hsa_circ_0032131 in PBMCs stimulated chondrocytes. A series of functional experiments revealed the relationship between hsa_circ_0032131 and the miR-502-5p/TRAF2 axis. To further determine whether XFC might treat OA through the interaction of circ_0032131 with the miR-502-5p/TRAF2 axis. CKK-8 assay and flow cytometry were conducted to detect the proliferation and apoptosis process of XFC-treated cells. Multiple experimental methods were utilized to detect the expression levels of inflammatory factors, extracellular matrix, and so on. The results demonstrated that the expression of hsa_circ_0032131 was obviously elevated in PBMCs of OA patients and correlated with clinical immuno-inflammatory factors and ECM indexes. Network pharmacology verified that the chief active ingredients of XFC exerted their roles mainly in the regulation of inflammation (IL1A, IL1B, IL4), extracellular matrix metabolism (MMP13, COL2A1), and tumour necrosis factor (TNF, TRAF2). In vitro experiments revealed that knockdown of circ_0032131 in PBMCs-stimulated chondrocytes inhibited apoptosis, inflammation and ECM degradation. Circ_0032131 was verified as a sponge of miR-502-5p by targeting, and TRAF2 was a direct target of miR-502-5p. In addition, rescue experiments verified that XFC blocked the effects of hsa_circ_0032131 overexpression on extracellular matrix, inflammation and cell viability. XFC has a favorable anti-inflammatory effect on OA, and its molecular mechanism was preliminarily elucidated.