Article

Postsynaptic dysfunction is associated with spatial and object recognition memory loss in a natural model of Alzheimer’s disease

Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, 2360102 Valparaíso, Chile.
Proceedings of the National Academy of Sciences (Impact Factor: 9.81). 08/2012; 109(34):13835-13840. DOI: 10.1073/pnas.1201209109

ABSTRACT Alzheimer’s disease (AD) is an age-related neurodegenerative disorder associated with progressive memory loss, severe dementia,
and hallmark neuropathological markers, such as deposition of amyloid-β (Aβ) peptides in senile plaques and accumulation of
hyperphosphorylated tau proteins in neurofibrillary tangles. Recent evidence obtained from transgenic mouse models suggests
that soluble, nonfibrillar Aβ oligomers may induce synaptic failure early in AD. Despite their undoubted value, these transgenic
models rely on genetic manipulations that represent the inherited and familial, but not the most abundant, sporadic form of
AD. A nontransgenic animal model that still develops hallmarks of AD would be an important step toward understanding how sporadic
AD is initiated. Here we show that starting between 12 and 36 mo of age, the rodent Octodon degus naturally develops neuropathological signs of AD, such as accumulation of Aβ oligomers and phosphorylated tau proteins. Moreover,
age-related changes in Aβ oligomers and tau phosphorylation levels are correlated with decreases in spatial and object recognition
memory, postsynaptic function, and synaptic plasticity. These findings validate O. degus as a suitable natural model for studying how sporadic AD may be initiated.

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