Functional analysis of endothelial anti–miR-214 or control miR-214 exosomes in vivo. Shown are sections of dissected Matrigel plugs that contained either no exosomes (A,D), control miR-214 exosomes (B,E), or anti–miR-214 exosomes (C,F) and had subcutaneously been grafted in mice. Sections were stained with hematoxylin and eosin (D-F) (red blood cell–containing blood vessel indicated with arrowheads), or CD31 (red) and DAPI (blue) (A-C). The graphs show (G) quantitation of murine endothelial cells that had infiltrated into the plugs and (H) blood vessel surfaces. Images were recorded at RT on an Olympus CX60 microscope using an Olympus UPlan Fl 20×/0.05 objective lens that was coupled to an Olympus DP71 camera operated using CellP software. Brightness of fluorescent images was enhanced using Adobe Photoshop software. Bars = 100 μm.