Fig. 1
USC-EVs are transported to the bone to enhance bone mass and strength in OVX-induced osteoporotic mice. a Morphology of USC-EVs under transmission electron microscopy. Scale bar: 50 nm. b Western blot analysis of exosomal markers in USC-EVs and USCs. c EV numbers of 100 μg USC-EVs from five different batches (E1, E2, E3, E4, and E5) were assessed by an EXOCET Exosome Quantitation kit. d Ex vivo fluorescent imaging of heart, liver, spleen, lungs, kidneys, brain, femurs, and tibias from vehicle-treated control OVX mice and OVX mice intravenously injected with the DiR-labeled USC-EVs for 3 h. Scale bar: 6 mm. e Fluorescence microscopy analysis of femur tissue sections from vehicle-treated OVX mice and OVX mice intravenously injected with the DiO-labeled USC-EVs for 3 h. TB: trabecular bone; BM: bone marrow. Scale bar: 50 µm. f Representative μCT images of femora. Scale bars: 1 mm. g–m Quantitative μCT analysis of the trabecular bone volume fraction (Tb. BV/TV; g), trabecular number (Tb. N; h), trabecular thickness (Tb. Th; i), trabecular separation (Tb. Sp; j), endosteal perimeter (Es. Pm; k), periosteal perimeter (Ps. Pm; l), and cortical thickness (Ct. Th; m). n = 10 per group. n Three-point bending measurement of femur ultimate load. n = 5 per group. The data are shown as the mean ± SD. *P < 0.05, **P < 0.01, ***P < 0.001
