Fig. 1

Ultrastructural analysis of the neurovascular unit (NVU) components in the cerebral cortex of WT and Mct8/Dio2KO mice. A Transmission electron microscopy (TEM) images of a representative capillary of the cerebral cortex in WT (a and c for P90; e, g, and i for P180) and Mct8/Dio2KO mice (b and d for P90; f, h, and j for P180). Filled arrows in c and g point at a continuous TJ. Hollow arrows in d and h point at discontinuous TJ. Asterisks in d mark transcytotic vesicles. Arrowheads in j delimit a loss of cohesion of endothelial cytoplasm. Perivascular astrocytes are colored in purple. Scale bar: 2.5 µm for a, b, e, and f; 250 nm for c, d, g, and h and 500 nm for i and j. B Quantification of the percentage of blood vessels showing different blood–brain barrier (BBB) disruption parameters in WT and Mct8/Dio2KO mice at P90 and P180. TJ  tight junction, LM  luminal membrane. C Quantification of the number of transcytotic vesicles and protrusions per vessel in WT and Mct8/Dio2KO mice at P90 and P180. D Quantification of the percentage of blood vessels that present an edematous perivascular astrocyte in WT and Mct8/Dio2KO mice at P90 and P180. E Western blot analysis of the expression of the main TJ proteins ZO-1 and occludin in the cerebral cortex of WT and Mct8/Dio2KO mice at P90 and P180. n = 5 for each experimental group for TEM studies, n = 5–7 for western blot studies at P90 and n = 5 for western blot studies at P180. Data are expressed as bar plots with individual values, mean ± SD. Assessment of the normality of data was performed by Shapiro–Wilk’s test. Parametric data sets were tested using a 2-tailed, unpaired Student’s t-test and non-parametric data sets by Mann–Whitney’s test. P-values *p < 0.05, **p < 0.01, ***p < 0.001, and ****p < 0.0001 were determined