Research Report Enriched environment and the effect of age on ischemic brain damage Deborah M. Saucier a, ⁎ , Jerome Y. Yager b , Edward A. Armstrong b , Avril Keller c , Sandy Shultz d a Behavioural Neuroscience, Room EP1146, Department of Neuroscience, 4401 University Dr., University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4 b Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada TG6 2R7 c Department of Psychology, University of Calgary, Calgary, Alberta, Canada T2N 1N4 d Neuroscience Program, University of Western Ontario, London, Ontario, Canada N6A 5B8 ARTICLE INFO ABSTRACT Article history: Accepted 12 July 2007 Available online 17 July 2007 Stroke affects all age groups from the newborn to the elderly. Previous work from our laboratory has shown that despite a greater susceptibility to brain damage, the immature brain recovers more rapidly and to a greater extent than does the more mature nervous system. In the current study, we examined the influence of environmental enrichment on the effects of age on the brain damaging effects of stroke. Rats aged 10, 63, and 180 days received ischemic insults following stereotactic intra-cerebral injection of endothelin-1, and resulting in injury to the right middle cerebral artery territory. Rats were then housed in either environmentally enriched cages, or standard cages for 60 days, after which they were sacrificed, and brain volumes determined for the extent of neurologic injury. Rats receiving the insult at 10 days of age showed a reduction of pathologic injury when housed in the enriched cages compared to standard. Conversely, rats receiving the insult at 180 days and housed environmentally enriched cages actually showed an increased volume of brain damage compared to controls. Our findings clearly indicate the dramatic influence of age on the extent of stroke and the influence of rehabilitative therapies. Behavioral correlation to morphologic alterations is required. Attempts at therapeutic interventions clearly need to be age-specific. © 2007 Published by Elsevier B.V. Keywords: Ischemia Aging Enrichment Recovery Brain 1. Introduction Stroke is increasingly recognized as a health hazard affecting the lives of individuals in all age groups (Bogousslavsky and Pierre, 1992; Bogousslavsky et al., 1988), not just the elderly. Incidence rates suggest that as many as 65–90 per 100,000 people between the ages of 15 and 49 years experience an ischemic cerebral infarct (Schoenberg et al., 1978). Recent data from the Canadian Pediatric Stroke Registry and others suggest that for children less than 15 years of age, the incidence of stroke is now reported to be as high as 8.0–13.0 per 100,000 children (deVeber, 2003; Kirkham and Hogan, 2004), likely an underestimate as stroke continues to be under- recognized in children. Cerebrovascular accidents in term and pre-term infants account for 25% of all strokes in the pediatric population (deVeber, 2002). BRAIN RESEARCH 1170 (2007) 31 – 38 ⁎ Corresponding author. Fax: +1 403 329 2775. E-mail address: Deborah.Saucier@uleth.ca (D.M. Saucier). Abbreviations: P10, postnatal day 10; P63, postnatal day 63; P180, postnatal day 180; GFAP, glial fibrillary acidic protein; M, mean 0006-8993/$ – see front matter © 2007 Published by Elsevier B.V. doi:10.1016/j.brainres.2007.07.020 available at www.sciencedirect.com www.elsevier.com/locate/brainres