Fig. 6

Bio-distribution and regenerative potential of systematically delivered MSC-EVs in murine model of hindlimb ischemia (HLI) in vivo. A (Left) Representative images of non-ischemic (N) and ischemic (I) limbs at 4 or 24 h after i.v. administration of GFP-positive MSC-EVs (green) or vehicle (PBS) by MAESTRO In-Vivo fluorescence imaging system. (Right) Average fluorescence emitted from limbs—presented as a ratio of fluorescence in ischemic (I) to non-ischemic (N) limb. Student t-test, comparison with animals at 4 h after EV administration. Red line represent signal of untretaed animals. B (Left) Representative images of blood flow measured prior limb ischemia injury (Control, w/o HLI) and at day 7, 14 and 21 after HLI and EV administration by Laser Doppler. (Right) Quantification of blood flow presented as a ratio of tissue reperfusion in ischemic (I) to perfusion in healthy non-ischemic (N) limb. Student t-test, comparison to vehicle (PBS)-treated animals (*P < 0.05). C Analysis of capillary density in muscle tissues at 21d post HLI with/without EV treatment. (Left) Representative images of CD31 (green) stained capillaries. Ischemic (I) and non-ischemic (N) tissue sections were co-stained with DAPI (blue) to visualize nuclei. (Right) Quantification of total number of the stained capillaries per microscopic field in skeletal muscles of vehicle- or MSC-EV-treated mice post mortem. Data are presented as ratio of total number of capillaries in ischemic (I) to non-ischemic (N) limb. Mann–Whitney test, comparison to vehicle (PBS)-treated animals (**P < 0.01)