Fig.1.

Identification of chondrocytes and exosomes isolated from human bone marrow stromal cells (hBMSCs) and exosome uptake by chondrocytes. A. Chondrocytes displaying spheroidal or elliptical morphology and contain a single nucleus (scale bar: 100 µm). B. Immunocytochemical staining of type II collagen (scale bar: 100 µm). C. Transmission electron microscopy images of hBMSCs-derived exosomes (scale bar: 0.2 µm). D. The size distribution of hBMSCs-derived exosomes by nanoparticle tracking analysis (NTA). E. Western blot analysis of exosome-specific CD9, CD63 and CD81 proteins. F. Exosomes were labelled with PKH67 (green fluorescent cell linker for general cell membrane labelling) (scale bar: 25 µm). G. PKH67-labelled exosomes were co-cultured with chondrocytes for 48 hours, and then chondrocytes were stained with ActinRed (red fluorescent) (scale bar: 25 µm). H. After co-culturing for a further 30 minutes, 4’, 6-diamidino-2-phenylindole (DAPI, blue fluorescent) was added (scale bar: 25 µm). I. Merged image of PKH67, ActinRed and DAPI. Most chondrocytes exhibited intracellular green fluorescence after incubation with exosomes (scale bar: 25 µm). PKH67-labelled exosomes were localized in the cytoplasm.