title: The effects of high- and low-risk environments on cognitive function in rats following 2-vessel occlusion of the carotid arteries: a behavioral study.
abstract: In a prospective study of environmental factors affecting cognitive recovery from stroke, adult male rats were reared for 3 months in a high-risk (relatively isolated, low activity, high-fat diet, high-stress) or low-risk (social, healthy diet, low-stress, physically active) environment. They then received cognitive testing to assess various aspects of learning and memory before undergoing 2-vessel occlusion (2VO) of the carotid arteries, or sham surgery. Rats were returned to their respective environments post-operatively. Relative to pre-operative levels, 2VO rats exhibited significant cognitive losses that were consistently greater in the high-risk group than its low-risk counterpart. As well, the high-risk 2VO group was impaired, relative to the low-risk 2VO group on tests of new learning introduced post-operatively. At 3-month follow-up testing, rats that had undergone 2VO surgery exhibited further decline on some tests but recovery on others, with recovery generally slower in the high-risk 2VO group. The high-risk environment also affected rats' pre-operative cognitive performance and, to a lesser extent, their performance following sham surgery. Overall, the study shows that rats experiencing cerebral ischemia are more likely to experience severe cognitive deficits if exposed to a high-risk environment and recover more slowly than ischemic rats in a more favorable environment. The results underscore the importance of lifestyle factors with respect to the impact of stroke on cognition and in assessing prospects for recovery of function.
authors.affiliation: Rotman Research Institute, Baycrest Centre, 3560 Bathurst Street, Toronto, Ontario, M6A 2E1, Canada. gwinocur@research.baycrest.org
authors.forename: Gordon
authors.initials: G
authors.lastname: Winocur
authors.forename: Charlie
authors.initials: C
authors.lastname: Thompson
authors.forename: Antoine
authors.initials: A
authors.lastname: Hakim
authors.forename: Carol
authors.initials: C
authors.lastname: Greenwood
mesh_terms: D000818:Animals; D001835:Body Weight; D002340:Carotid Artery Diseases / Q000150:complications*; D002343:Carotid Artery, Internal / Q000473:pathology*; D003072:Cognition Disorders / Q000175:diagnosis / Q000209:etiology*; D003213:Conditioning, Psychological; D003463:Cues; D004195:Disease Models, Animal; D004777:Environment; D005500:Follow-Up Studies; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000209:etiology; D009483:Neuropsychological Tests; D051381:Rats; D020318:Rats, Long-Evans; D012307:Risk Factors; D013028:Space Perception / Q000502:physiology
keywords: 2-Vessel occlusion; Cognitive function; Prospective study; Risk factor