Onset of hippocampus-dependent memory impairments in 5XFAD transgenic mouse model of Alzheimer's disease

authors

  • Girard Stéphane D.
  • Jacquet Marlyse
  • Baranger Kévin
  • Migliorati Martine
  • Escoffier Guy
  • Bernard Anne
  • Khrestchatisky Michel
  • Féron François
  • Rivera Santiago
  • Roman François S.
  • Marchetti Evelyne

keywords

  • Behavioral assessment
  • Astrocytes
  • Amyloid plaques
  • Age of Onset
  • Amyloid
  • Plaque
  • Organ Size
  • Olfactory Bulb
  • Presenilin-1
  • Transgenic
  • Maze Learning
  • Magnetic Resonance Imaging
  • Amyloid beta-Protein Precursor
  • Mice
  • Alzheimer Disease
  • Male
  • Animals
  • Corpus Striatum
  • Gliosis
  • Hippocampus
  • Learning Disorders
  • Memory Disorders
  • Olfactory tubing maze
  • Point Mutation
  • Smell

abstract

The 5XFAD mice are an early-onset transgenic model of Alzheimer's disease (AD) in which amyloid plaques are first observed between two and four months of age in the cortical layer five and in the subiculum of the hippocampal formation. Although cognitive alterations have been described in these mice, there are no studies that focused on the onset of hippocampus-dependent memory deficits, which are a hallmark of the prodromal stage of AD. To identify when the first learning and memory impairments appear, 5XFAD mice of two, four, and six months of age were compared with their respective wild-type littermates using the olfactory tubing maze, which is a very sensitive hippocampal-dependent task. Deficits in learning and memory started at four months with a substantial increase at six months of age while no olfactory impairments were observed. The volumetric study using magnetic resonance imaging of the whole brain and specific areas (olfactory bulb, striatum, and hippocampus) did not reveal neuro-anatomical difference. Slight memory deficits appeared at 4 months of age in correlation with an increased astrogliosis and amyloid plaque formation. This early impairment in learning and memory related to the hippocampal dysfunction is particularly suited to assess preclinical therapeutic strategies aiming to delay or suppress the onset of AD.

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