Fig. 3

Magnetic resonance imaging 2 months after 5 × tamoxifen induction. a High-resolution T2-weighted MRI images of control and DTA mice. DTA mice displayed a reduction of the hippocampal dimensions in high-resolution T2-weighted MRI in vivo (top coronal view, bottom axial view). Dentate gyrus and CA region exhibited a clear rarefaction, making these regions in DTA mice almost undetectable. b Volumetric comparison of various brain regions. DTA mice showed atrophy of olfactory bulb, whole cerebrum (without hippocampus and ventricles), hippocampus, and cerebellum. c Comparison of Jacobian determinants. Maps of z-score derived from the comparison of Jacobian determinants, overlaid on the study template, revealed lower volume of the cortex (particularly in the region of layer V), the hippocampus and its projection regions in DTA mice compared to controls. A z-score lower than -2.57 corresponds to a false discovery rate lower than 1%. d–f Comparison of vasculature and perfusion by IVIM-MRI and DSC-MRI. DTA mice showed higher cerebral blood volume in the hippocampus as shown independently by IVIM-MRI d and DSC-MRI e. In addition, the vascular volume fraction was enhanced in the cortex of DTA mice. The cerebral blood flow f was increased in all analyzed brain regions. g Comparison of brain water content, determined by IVIM-MRI: Apparent diffusion coefficient (ADC) was increased in cortex and hippocampus of DTA mice, indicating higher water content in brain regions particularly affected by diphtheria toxin expression; MRI data from 6–8 mice/group, mean ± SD presented. h Molecular quantification of brain water, dry brain mass and blood brain barrier function in additional DTA and control mice at 2 months after encephalitis induction. Using this independent method, brains of DTA mice showed again higher water content and decreased brain mass. Increased extravasation of Evans blue and fluorescein indicate lasting blood–brain-barrier dysfunction; data from 5 mice/group, mean ± SD given; 2-tailed unpaired Welch’s corrected t-tests or Mann–Whitney U-tests. All experiments in Fig. 3 were performed with 5 × tamoxifen DTA mice