Human-like rodent amyloid-β-peptide determines Alzheimer pathology in aged wild-type Octodon degu

It is generally accepted that human Alzheimer's disease (AD) neuropathology markers are completely absent in rodent brains. We report here that an aged wild-type South American rodent, Octodon degu, expresses neuronal β-amyloid precursor protein (β-APP695) displaying both intracellular and extracellular deposits of amyloid-β-peptide (Aβ), intracellular accumulations of tau-protein and ubiquitin, a strong astrocytic response and acetylcholinesterase (AChE)-rich pyramidal neurons. The high amino acid homology (97.5%) between deguAβ and humanAβ sequences is probably a major factor in the appearance of AD markers in this aged rodent. Our results indicate that aged O. degu constitutes the first wild-type rodent model for neurodegenerative processes associated to AD.