Human umbilical cord mesenchymal stem cell-derived exosomal miR-199a-3p inhibits the MAPK4/NF-κB signaling pathway to relieve osteoarthritis

Figure 6 Human umbilical cord mesenchymal stem cell-derived exosomes relieve osteoarthritis progression in vivo through the delivery of miR-199a-3p. A: Hematoxylin and eosin staining was used to examine the pathological conditions of rat articular cartilage tissues (scale bar = 25 μm); B: Safranin O/fast green staining was used to assess the quantity of chondrocytes within rat articular cartilage tissues (scale bar = 25 μm); C: Examination of cartilage differentiation in rat articular cartilage tissues via toluidine blue staining (scale bar = 25 μm); D: Interleukin-6, interleukin-8, and tumor necrosis factor-α levels in rat articular cartilage tissue were detected via enzyme-linked immunosorbent assay; E: Evaluation of cell apoptosis in rat articular cartilage tissue via terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-nick end labelling staining (scale bar = 100 μm); F: Western blot analysis was used to measure the expression of Bcl-2 and Bax apoptosis-related proteins; G: Quantitative real-time polymerase chain reaction was used to quantify miR-199a-3p expression in rat cartilage tissues; H: Immunohistochemistry was used to determine the presence of mitogen-activated protein kinase 4 in rat articular cartilage tissues (scale bar = 25 μm); I: P-nuclear factor-kappaB p65 expression in rat articular cartilage tissues was evaluated through western blot analysis. ^bP < 0.01, ^cP < 0.001. OA: Osteoarthritis; Exos: Exosomes; HE: Hematoxylin and eosin; TB: Toluidine blue; SOFG: Safranin O/fast green; NF-κB: Nuclear factor-kappaB; IL: Interleukin; TNF: Tumor necrosis factor; DAPI: 4’,6-diamidino-2-phenylindole; TUNEL: Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-nick end labelling.