Microvacuolation of the cerebral WM in 20-month-old TgPAC-Notch3
mice. (A-B) Representative toluidine blue stained 1 μm resin sections of the corpus callosum showing abundant lesions (arrows) in the TgPAC-Notch3R169C
(B) but not in the control (A). (C-F) Representative electron micrographs of the corpus callosum from a control (C) and a TgPAC-Notch3R169C
(D-F), showing multiple membrane-bound vacuoles (D-E, colored in pink), including numerous inframicrometric vacuoles (D, white arrows), as well as myelin whorls (E, colored in blue and arrowheads) in the TgPAC-Notch3R169C
(D, E) contrasting with rare vacuoles in the control (C). (F) Inset of the boxed area in (E) containing five myelin whorls; Inset has been left uncolored to improve visualization. (G-H) Diagrams showing the % of vacuoles and myelin whorls (G) and the distribution of vacuole diameter (H) in the corpus callosum of TgPAC-Notch3R169C mice (n = 4), indicating that the majority of WM lesions are infra-micrometric vacuoles. O, oligodendrocytes (colored in green); A, astrocyte (colored in purple); M, microglia (colored in brown); C, capillary (colored in yellow). Scale bar represents 30 μm (A-B), 5 μm (C-E) and 1.5 μm (F).