Absence of increase in endothelial tight junction proteins in IAs of PCK rats. (A) Representative ZO-1 immunostaining of the right OA-ACA bifurcation of a WT rat killed 8 weeks post-surgery. The white squares indicate two zones of interest: the OA-ACA bifurcation where IAs develop and a straight part of the ACA. Scale bar, 50 μm. (B–D) Representative CD31 (B), ZO-1 (C) and CLDN5 (D) immunostainings (in green). Nuclei are stained with DAPI (in blue), and internal elastic laminae are stained with Evans blue (in red). * denotes lumen of the vessel. Scale bar, 5 μm. (E–J), Quantifications of CD31 (E and F), ZO-1 (G and H) and CLDN5 (I and J) immunostainings on WT (n = 7–8/group) and PCK (n = 4–11/group) rats killed without surgery, at 2 and 4 weeks post-surgery in the ACA (E, G, and I) and at the OA-ACA bifurcation (F, H and J). Kruskal–Wallis test with Dunn’s multiple comparison test with WT and PCK without surgery. *P < 0.05, **P < 0.01, ***P < 0.001.