FIGURE 6.

MiR-320a was highly enriched in exosomes from mesenchymal stem cells (MSCs). (A) The morphology of the fifth passage of MSCs observed by the inverted microscope (×100). (B) The formation of osteoblast, adipocytes, and chondrocytes analyzed by cytochemical staining performed by Alizarin Red (I, ×100), oil red O (II, ×400), and Alcian blue (III, ×200), respectively. (C) The expression of surface marker proteins associated with MSCs determined by flow cytometry. (D) Observation of the ultrastructure of exosomes by transmission electron microscope (TEM) (×5,000). (E) The expression of CD9 and CD63 determined by Western blot analysis. (F) The exosome concentration and particle size by nanoparticle tracking analysis (NTA). (G) The expression of miR-320a in rheumatoid arthritis fibroblast-like synoviocytes (RA-FLSs) after co-culture with exosomes measured by RT-qPCR. (H) The uptake of MSC-derived exosomes by RA-FLSs (×200) observed by laser confocal microscopy. Statistical analysis was performed using an independent sample t test. Data were expressed as mean ± standard deviation. *p < 0.05 compared with MSCs or RA-FLSs cultured with PBS.