Abstract: Objective To investigate the mechanism that mediates the inhibitory effect of Xinfeng Capsule (XFC) on interleukin (IL)-1β-induced impairment of chondrocytes. Methods XFC-medicated serum was collected from SD rats with XFC gavage, and its optimal concentration for chondrocyte treatment was determined using Cell Counting Kit-8 assay and flow cytometry. Dual luciferase reporter analysis was performed to analyze the targeting relationship between miR-502-5p and TRAF2. In cultured human chondrocytes induced with IL-1β, the effects of transfection with miR-502-5p inhibitor and XFC-medicated serum, alone or in combination, on expression levels of IL-1β, tumor necrosis factor-α (TNF-α), IL-4, and IL-10 were examined with ELISA, and the changes in the expressions of collagen type II alpha 1 (COL2A1), matrix metalloproteinase 13 (MMP13), adisintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS5), and miR-502-5p/TRAF2/NF-κB axis gene expression were detected using RT-qPCR, Western blotting, and immunofluorescence assay. Results In cultured human chondrocytes, treatment with IL-1β significantly decreased the cell viability, increased cell apoptosis rate, lowered miR-502-5p, IL-4, IL-10, and COL2A1 expressions, and enhanced IL-1β, TNF-α, ADAMTS5, MMP13, TRAF2, and NF-κB p65 expressions (P<0.05), and these changes were significantly improved by treatment with XFC-medicated serum at the optimal concentration of 20% (P<0.05). Transfection of the chondrocytes with miR-502-5p inhibitor resulted in elevated expressions of IL-1β, TNF-α, ADAMTS5, MMP13, TRAF2, and NF-κB p65 and lowered expressions of miR-502- 5p, IL-4, IL-10, and COL2A1, and XFC-medicated serum obviously reversed the effects of miR-502-5p inhibitor. Conclusion XFC can inhibit IL-1β-induced inflammatory response and ECM degradation in cultured human chondrocytes possibly by regulating the miR-502-5p/TRAF2/NF-κB axis.

Key words: miR-502-5p; osteoarthritis; Xinfeng Capsule; inflammation; extracellular matrix