Figure 4
From: Aβ reduction in BACE1 heterozygous null 5XFAD mice is associated with transgenic APP level
Amyloid plaques are reduced in female but not male 5XFAD/BACE1 +/− mice. Free-floating 30 μm brain sections from 6 month-old male and female 5XFAD/BACE1+/+ and 5XFAD/BACE1+/− mice were co-stained with clone 3D6, an antibody to the N-terminus of Aβ (green), anti-BACE1 antibody (red), and DAPI (blue) and imaged by fluorescence confocal microscopy. Three mice of each sex and genotype combination were analyzed for a total of twelve mice, and all images were captured using identical confocal camera and laser configurations. The representative images of mid-dorsal cortex and hippocampus shown here are from individuals that had Aβ42 dot blot values near the mean of each group. Amyloid plaque densities in Layer 5 of the cortex correlate well with Aβ42 levels determined by dot blot. Female 5XFAD/BACE1+/+ mice have the highest plaque density, with 5XFAD/BACE1+/− females showing a marked reduction in amyloid deposits by comparison. In contrast, male 5XFAD/BACE1+/+ and 5XFAD/BACE1+/− mice had similar plaque densities, and both had fewer plaques than 5XFAD/BACE1+/+ female mice. These histological results support our biochemical data showing that Aβ42 levels are reduced in 5XFAD/BACE1+/− female, but not male, mice (Figure 3). Size bar represents 100 μm.