Fig. 2
Detection of Aβ in the huAPPwt mice inoculated with AD or CTRL brain. Mice inoculated with human brain homogenates were euthanized 18 months after the inoculation. Brain sections were stained with anti-Aβ (4G8-biotinylated) antibody. Staining was detected in the region surrounding the alveus of almost all the mice inoculated with the AD brains (a–c, arrows) but not the CTRL-brains (e–f). There was no staining in the hippocampus or cortex of the inoculated mice. 4G8 staining was not observed in the close vicinity of blood vessels (asterisk) as shown in a mouse inoculated with AD brain extract (c). Congo red did not stain any deposits in the inoculated mice, as shown in the alveus of an AD- (g) or CTRL-inoculated animal (h). 4G8-labeling was quantified in the alveus (d). First, regions of interest corresponding to the alveus were defined as ribbons of 88 µm wide centered on the virtual ventricle that borders the alveus of the hippocampus. Amyloid burden in this region was defined, using a thresholding method, as the percentage of surface occupied by the 4G8-staining inside the regions of interest. This analysis showed significant difference between CTRL and AD mice (U = 9; p = 0.001)