Fig. 2

Hp OMVs administered systemically or orally reach the brain in BALB/c mice. a Scheme of the in vivo experimental design. DiR-labeled Hp OMVs were administered to Male BALB/c mice orally or via the tail vein. The biodistribution of labeled OMVs was evaluated using the FX PRO (Bruker) imaging system. b Ex vivo fluorescence images of dissected organs following different treatments. Mice injected via the tail vein with control, control-DiR, 10 or 100 µg of DiR-OMVs, were killed after 24 h for optical imaging (scale bar = 1 cm). c Quantification of fluorescence intensity (arbitrary units) in the mouse brain following the treatments indicated in b. d Ex vivo fluorescence images of brain hemispheres following the indicated treatments, 72 h after injection with 5, 10, or 20 µg of DiR-OMVs into the tail vein (scale bar = 1 cm). e Quantification of fluorescent signal intensities of the experiment shown in d performed with the Bruker Molecular Imaging Software. Values in the graph represent means ± S.E.M. of fluorescence intensity (arbitrary units); n = 3. *p < 0.05, **p < 0.01. f Ex vivo fluorescence images of whole brains and their corresponding hemispheres from mice 1 to 3 days after oral gavage administration of 100 µg of DiR-OMVs (24 h, 48 h, and 72 h) (scale bar = 1 cm). For comparison, a mouse was injected with 10 µg of OMVs via the tail vein. g Confocal immunofluorescence of coronal brain tissue sections of a mouse injected with 10 µg of Hp OMVs stained with an anti-UreB subunit antibody (red). DAPI in blue shows nuclear staining (scale bar = 20 µm)