TJ protein expression is reduced in areas of vascular breakdown.

(A) Representative confocal images from the frontal cortex of an uninfected mouse (left) or a symptomatic mouse at d6 p.i. (middle, right) following i.v. injection of Evans blue dye (white) to visualize vascular leakage. (n = 4 mice per group). (B) Representative confocal images of cerebral blood vessels from an uninfected mouse (top) or a symptomatic mouse at d6 p.i. (bottom) following immunohistochemical staining for CD31⁺ ECs (red) and the TJ protein claudin-5 (green). The volumetric mask of the blood vessel generated from the CD31 signal is shown in the second panel. (C) The bar graph shows quantification of the data in (B) plus areas of no vascular hemorrhage from the same symptomatic mice at d6 p.i. Each symbol represents one blood vessel. (n = 4 mice per group, 1 section per mouse, 3–4 images per brain region). Asterisks denote statistical significance (*P<0.05).