Fig. 3

Increased Aβ deposition in the alveus of 11-month-old APP_swe/PS1_dE9 mice inoculated with AD-huAPP_wt brain homogenate. APP_swe/PS1_dE9 mice were inoculated with apparently amyloid deposit-free hippocampus extracts from huAPP_wt mice previously inoculated with human brain homogenates and euthanized 18 months after the inoculation. Aβ (biotinylated 4G8) stained brain sections from the APP_swe/PS1_dE9 mice showed plaques in the hippocampus of all mice (a–d). Aβ deposition was also seen in regions surrounding the alveus of the mice inoculated with AD-huAPP_wt brains (a–b, arrows). 4G8 staining did not involve blood vessels (asterisk) as highlighted here in a mouse inoculated with AD-huAPP_wt (h). 4G8-positive load (e) and the number of plaques per surface unit (f) were significantly increased in the region surrounding the alveus of AD-APP_swe/PS1_dE9 mice compared to the CTRL-APP_swe/PS1_dE9 (U = 1, p = 0.004 **, and U = 3, p = 0.015 *, respectively). g Amyloid load was not different in the hippocampus of AD-APPswe/PS1dE9 and CTRL-APPswe/PS1dE9 mice (U = 11, p = 0.3). Congo red stained brain sections from the APP_swe/PS1_dE9 mice showed amyloid plaques (arrows) in the hippocampus and cortex of mice from AD (i) and CTRL groups (j)