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

Figure 1 Human umbilical cord mesenchymal stem cell-derived exosomes relieve interleukin-1β-induced inflammation and apoptosis in chondrocytes. A: Transmission electron microscopy images of the human umbilical cord mesenchymal stem cell-derived exosomes (scale bar = 100 nm); B: Particle size distribution of the purified human umbilical cord mesenchymal stem cell-derived exosomes determined by nanoparticle tracking analysis; C: Detection of CD63 and CD81 exosome surface markers by western blot analysis; D: PKH-67 tracking experiments verified the uptake of exosomes by CHON-001 cells (scale bar = 10 μm); E: Enzyme-linked immunosorbent assay was used to detect interleukin-6, interleukin-8, and tumor necrosis factor-α in CHON-001 cells; F: CCK-8 detection of CHON-001 cell viability; G: Apoptosis of CHON-001 cells detected via terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-nick end labelling staining (scale bar = 100 μm); H: In CHON-001 cells, Bcl-2 and Bax expression levels were detected by western blot analysis. ^aP < 0.05, ^bP < 0.01, ^cP < 0.001. hUC-MSCs: Human umbilical cord mesenchymal stem cells; Exos: Exosomes; DAPI: 4’,6-diamidino-2-phenylindole; IL: Interleukin; TNF: Tumor necrosis factor; OD: Optical density; TUNEL: Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-nick end labelling.