Fig. 5

BMSCs promote the osteogenic differentiation of BMSCs in aged osteoporotic rats after fatigue loading. A Saucer-like structures of exosomes observed by transmission electron microscopy (TEM). Scale bar, 100 nm. B Positive exosomal marker proteins, CD9, CD81, and TSG101, in exosome-enriched preparations as detected by WB. C Particle size distribution of serum exosomes as analysed by DLS. D Illustration of BMSCs in bone microdamage model rats induced by serum exosomes from young rats. E Confocal fluorescence images of BMSCs and exosomes. F Representative images of the Alizarin Red staining of BMSCs treated with serum exosomes or PBS (control). G mRNA expression levels of ALP, OCN, Collagen I, and Runx2 in BMSCs treated with serum exosomes or PBS. (H) Levels of collagen I and Runx2 in BMSCs treated with serum exosomes or PBS as detected by WB. The data are expressed as the mean ± SEM. *P < 0.05, **P < 0.01, ****P < 0.0001 vs. the PBS group (n = 3)