Fig. 1.

Characterization and functional validation of exosomes derived from MSCs (Exo). a Phenotypic analysis of cell surface antigens of MSCs by flow cytometry. b Cup-shaped morphology of purified Exo assessed by transmission electron microscopy. Scale bar = 200 nm. c The particle size, particle concentration, and video frame of Exo analyzed by nanoparticle tracking analysis. d Representative images of Western blot showing the exosomal protein markers. e Representative confocal images showing that red fluorescence dye PKH26-labeled Exo (Exo-PKH26) were endocytosed by MSCs after12-h incubation. Scale bar = 60 μm. f Distribution of Exo-PKH26 in the infarcted heart on day 1, day 3, and day 7 post injection. Scale bar = 50 μm. g Quantification of PKH26+ cells in f (n = 5). (A-G) n = 5. All data are mean ± SEM. Statistical analysis was performed with one-way ANOVA followed by Tukey’s test. **p < 0.01, ****p < 0.0001