Fig. 2

AD-like aged degu brains show greater Aβ deposits relative to age matched controls. (a–h) Confocal fluorescence micrographs demonstrate markedly more Aβ deposits (red) in degu coronal brain slices stained with 6E10 monoclonal antibody anti-Aβ(1–16) N-terminal epitope. Representative views of cortex including somatosensory cortex (SSC) and hippocampus dentate gyrus (DG) are from Non-AD (a, b) and AD-like aged degu (c and d, arrows indicate 6E10-positive Aβ deposits) brains. Images highlight the massive Aβ neuritic-plaque-like deposits in the retrosplenial cortex (RSC, e, f), cytoplasmic deposition in hippocampal CA1 (g, arrows indicate 6E10-positive Aβ deposits), and a Z-stack 3D reconstruction view of a large plaque in a cortical area in AD-like aged degus (h). i, j Representative immunofluorescence microscopic views covering hippocampal DG and a cortex area of coronal slices of an aged 5xFAD brain stained same as the degu sections. All sections were counterstained with DAPI for nuclei as blue. Note that overlap in DAPI (blue) and 6E10 (red) signal results in magenta color. k The 6E10-positive deposits per cm² is quantified in AD-like and Non-AD aged degus (N = 6 for each degu group) in the SC and dorsal hippocampus (dHIP). Results show statistical significance for the 6E10 + plaques per cm² between AD-like and Non-AD groups. **p < 0.01. (l, m) Analysis of Aβ40 and Aβ42 in formic acid extracts from Non-AD and AD-like degu brain slices by ELISA demonstrates increased levels of Aβ40 and Aβ42 in AD-like compared to Non-AD degu brains; whereas AD-like females show higher levels than AD-like males (N = 3 for AD-like male and female group). Measurements were performed in triplicate for each assay for each animal. Results show statistical significance between non-AD and AD-like degus (***p < 0.001) as well as males versus females (*p < 0.05) in AD-like group