Figure 1. Identification and internalization of EC-Exos. Exosomes were isolated from samples with a total exosome extraction kit or ultrafiltration from mouse vascular EC medium. (A) Morphological features of EC-Exos were observed via transmission electron microscopy. (B) Particle sizes of exosomes were monitored with NTA. The X-axis shows the particle sizes in the sample, and the Y-axis shows the concentrations of particles of a certain size. Total protein was extracted from exosomes and analyzed with western blotting. (C, D) Representative images showing the expression of the exosome surface markers Alix, CD81, CD9 and Tsg101. PKH26-labeled exosomes were co-cultured with ATDC5 cells for 3 hours. (E) Quantitative analysis of the uptake rates of exosomes in ATDC5. (F) Immunofluorescence images showing the uptake of EC-Exos by ATDC5. The nuclei were labeled with DAPI (blue), and PKH26-labeled exosomes were internalized by ATDC5 cells (red). ***p<0.001, **p<0.01, *p<0.05 (n = 3).