Overexpression of APP provides neuroprotection in the absence of functional benefit following middle cerebral artery occlusion in rats

Eur J Neurosci. 2007 Oct;26(7):1845-52. doi: 10.1111/j.1460-9568.2007.05807.x.

Abstract

Cerebral ischaemia leads to a transient accumulation of beta-amyloid precursor protein (APP) and beta-amyloid (Abeta) peptides adjacent to the ischaemic lesion. There is conflicting evidence that APP/Abeta fragments may either enhance neuronal plasticity or be neurotoxic. The aim of the current study was to assess the effect of overexpression of human APP in rats on functional recovery following cerebral ischaemia. Adult APP-overexpressing (hAPP695 Tg) rats subjected to transient middle cerebral artery occlusion (MCAO) had significantly smaller infarct volumes than non-transgenic littermates, yet did not perform better on a series of sensorimotor or learning tests during a 6-month follow-up period. In fact, transgenic animals were found to be significantly more impaired in both the beam-walking and Morris water maze tests following MCAO. Immunohistochemistry showed human Abeta-positive staining in the cortex and hippocampus of APP transgenic rats. The present data suggest that while overexpression of APP in rats may provide some histological neuroprotection in the event of cerebral ischaemia, this does not translate into significant functional recovery.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyloid beta-Protein Precursor / genetics
  • Amyloid beta-Protein Precursor / metabolism*
  • Analysis of Variance
  • Animals
  • Animals, Genetically Modified
  • Behavior, Animal
  • Brain Chemistry / genetics
  • Brain Infarction / etiology*
  • Brain Infarction / prevention & control*
  • Conditioning, Classical / physiology
  • Fear / physiology
  • Gene Expression / genetics
  • Gene Expression / physiology*
  • Humans
  • Infarction, Middle Cerebral Artery / complications*
  • Male
  • Maze Learning / physiology
  • Psychomotor Performance / physiology
  • Rats
  • Recovery of Function / genetics
  • Recovery of Function / physiology*
  • Time Factors

Substances

  • Amyloid beta-Protein Precursor