Chonggu Granules Improve Cartilage Matrix Metabolism in Knee Osteoarthritis via the miR-148a-3p/Wnt/β-Catenin Pathway.

PURPOSE: This study aims to explore the effect and underlying mechanism of Chonggu Granules (CGG) in knee osteoarthritis (KOA) in rats.

METHODS: A papain-induced KOA model was established in rats. The pathological alterations of extracellular matrix in rat cartilage tissues were observed through hematoxylin and eosin (H&E) staining, followed by Mankin score for quantitative scoring. The ultrastructure of cartilage extracellular matrix was examined under a transmission electron microscopy (TEM). ELISA was used to measure the levels of IL-6, TNF-α, and IL-1β in rat serum. Immunofluorescence was performed for assessing the levels of MMP-3, MMP-13, and Col2al in rat cartilage. Western blot was used to identify the protein expressions of wnt1, GSK-3β, β-catenin, and Aggrecan in rat cartilage. The mRNA relative expressions of miR-148a-3p, wnt1, β-catenin, and GSK-3β in rat cartilage were detected by RT-PCR. Luciferase reporter gene was used to detect the target genes of miR-148a-3p.

RESULTS: CGG significantly improved articular cartilage tissue and extracellular matrix metabolism compared to the model group as indicated by H&E, Mankin score, and TEM data. Moreover, low, medium, and high doses of CGG reduced the levels of IL-6, TNF-α, IL-1β, MMP-3, and MMP-13 in serum to varying degrees but increased the levels of Col2al and Aggrecan. Mechanistically, CGG targeted wnt1 by increasing the expression of miR-148a-3p in a dose-dependent manner, thereby downregulating the mRNA and protein expressions of β-catenin in cartilage tissue and upregulating the mRNA and protein expressions of GSK-3β.

CONCLUSION: CGG may control the miR-148a-3p/wnt/β-catenin signaling pathway to decrease the levels of its downstream target genes MMP-13 and MMP-3, increase the expressions of Col2al and Aggrecan, and downregulate the contents of inflammatory cytokines IL-6, TNF-α, and IL-1β, thereby improving the metabolism of cartilage extracellular matrix and alleviating the degeneration of articular cartilage in KOA.