Figure 7

Confocal microscopy of blood–brain barrier. Cortical sections of perfusion fixed brain from Gcdh ^−/− and heterozygous (Gcdh ^−/+) mice were fluorescently labeled for astrocytes with GFAP (green), occludin (red) and nuclei with DAPI (blue). a Gcdh ^−/+ mouse cortex shows astrocyte end-feet (green) outlining larger blood vessel with complete ring of occludin between endothelial cells representing intact blood brain barrier. b Similar section of Gcdh ^−/− mouse on a standard diet (SD) showing incomplete ring of occludin at blood–brain barrier. c Within 36-hours of lysine diet exposure in the Gcdh ^−/− mouse, occludin is no longer between endothelial cells and appears to be withdrawn from the vessel lumen. d After 6-weeks of lysine diet exposure in Gcdh ^−/− mice, signal from occludin is not detectable at blood–brain barrier. e and f VEGF was significantly increased in cortex of Gcdh ^−/− mice compared to control and further increased after 36-hours of high lysine diet in cortex (e) and striatum (f). (± S.E.M, ** p < 0.05 compared to standard diet control, * p < 0.02, n = 3-4 per group).