The cognitive and histopathological effects of chronic 4-vessel occlusion in rats depend on the set of vessels occluded and the age of the animals

Behav Brain Res. 2009 Feb 11;197(2):378-87. doi: 10.1016/j.bbr.2008.10.023. Epub 2008 Oct 21.

Abstract

Continuing previous efforts to develop the 4-vessel occlusion (4-VO) model of chronic cerebral hypoperfusion (CCH), here we evaluated whether permanent, stepwise 4-VO causes both learning deficits, hippocampal neurodegeneration and retinal lesion in young, middle-aged or aged rats. Chronic 4-VO was induced by ligation of different sets of vessels, i.e., the vertebral arteries (VA) plus common carotid arteries (CCA) (4-VO/CCA model) or the VA plus internal carotid arteries (ICA) (4-VO/ICA model) with a 1-week interstage interval. Forty days after the 4-VO, the rats were tested for spatial learning impairment, and then examined for hypoxic/ischemic damage. Young, 4-VO/CCA rats exhibited cognitive impairment, hippocampal neurodegeneration and retinal lesion (p<0.0001-0.05). After 4-VO/ICA, neither young nor middle-aged rats exhibited any learning deficits, hippocampal or retinal damage. In aged rats, chronic 4-VO/ICA caused a mild learning deficit (p<0.05). A significant effect of training was observed for the old, sham-operated rats (p<0.0001-0.001), but not for the aged 4-VO/ICA rats (p>0.05). On average, hippocampal cell density did not change after 4-VO/ICA in aged rats, but 3 of 10 subjects exhibited reduced pyramidal cell counts in all hippocampal subfields. Retinal morphology appeared to be unaffected in the 4-VO/ICA aged rats. These data suggest that the 4-VO/ICA model, but not the 4-VO/CCA model, is a suitable paradigm to study the behavioral outcome of CCH given the preservation of the retina after 4-VO/ICA. Moreover, the age at which 4-VO/ICA occurs seems to be an important factor for determining the behavioral and neuropathological changes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Age Factors
  • Analysis of Variance
  • Animals
  • Brain Damage, Chronic / pathology
  • Brain Damage, Chronic / physiopathology*
  • Brain Ischemia / pathology
  • Brain Ischemia / physiopathology*
  • Carotid Artery, Common / physiopathology
  • Carotid Artery, Common / surgery
  • Carotid Artery, Internal / physiopathology
  • Carotid Artery, Internal / surgery
  • Cell Count / methods
  • Cerebrovascular Circulation / physiology*
  • Cognition / physiology*
  • Disease Models, Animal
  • Hippocampus / pathology
  • Ligation / methods
  • Male
  • Maze Learning / physiology
  • Memory / physiology
  • Pyramidal Cells / pathology
  • Rats
  • Rats, Wistar
  • Retina / pathology
  • Space Perception / physiology
  • Vertebral Artery / physiopathology
  • Vertebral Artery / surgery