Exosomes Extracted from Human Umbilical Cord MSCs Contribute to Osteoarthritic Cartilage and Chondrocytes Repair Through Enhancing Autophagy While Suppressing the Wnt/β-Catenin Pathway.

backgroundOsteoarthritis (OA), a widespread chronic joint disorder mainly affecting the elderly, currently lacks a definitive cure. This study investigated the efficacy of exosomes (Exos) extracted from human umbilical cord MSCs (hucMSCs) in the treatment of OA, and preliminarily explored the mechanisms.

methodsA rat osteoarthritis model was constructed by surgical induction. The cartilage morphology was observed after pathological staining; expression of cartilage matrix protein, autophagy-related protein and β-catenin were detected by immunohistochemistry; and inflammatory factors in serum were tested by ELISA. In cellular experiments, human primary chondrocytes were induced with IL-1β to build the OA microenvironment. The levels of relevant proteins in each group were analyzed.

resultsComparing to the OA model, the Exos treatment showed positive effects in reducing OARSI score and Mankin score, decreasing joint space stenosis, promoting matrix synthesis, increasing autophagy, and decreasing β-catenin. The results of the cellular experiments were consistent with those from the animal experiments. However, the Wnt/β-catenin pathway was greatly activated, the levels of matrix proteins and autophagy were distinctly reduced in the Exos + LiCl group comparing to the exosome-treated group.

conclusionhucMSCs-Exos effectively attenuated the pathological damage of OA cartilage and chondrocytes, promoted the synthesis of cartilage matrix, reduced inflammation, suppressed the Wnt/β-catenin pathway, and enhanced autophagy which promoted the repair of OA cartilage.