Synovial mesenchymal stem cell-derived exosomes delivering GRPEL1 activate PINK1-mediated mitophagy to promote cartilage repair in arthritis

Figure 7 Cartilage injury assessment in rat osteoarthritis model after synovial mesenchymal stem cell-derived exosomes GrpE-like 1 delivery. The figure evaluates cartilage repair and osteoarthritis progression across experimental groups. A: International Cartilage Repair Society macroscopic scoring of rat knee joints, providing comprehensive visual assessment of cartilage damage; B: Hematoxylin and eosin staining of knee cartilage tissue, revealing histological structural changes and inflammatory responses, red arrows indicate areas of cartilage surface erosion; yellow arrows indicate chondrocyte clustering; black arrows indicate matrix degradation or fissures; C: Safranin-O-Fast Green staining, demonstrating proteoglycan content and matrix integrity in cartilage tissue; D: Osteoarthritis Research Society International scoring, quantitatively assessing cartilage degeneration severity. Scale bar: 100 μm and 20 μm. ^bP < 0.01 vs control; ^dP < 0.01 vs OA; ^fP < 0.01 vs OA + Exo-oeNC; ^gP < 0.05 vs OA + Exo-shNC. ICRS: International Cartilage Repair Society; OA: Osteoarthritis; Exo: Exosome; OARSI: Osteoarthritis research society international.