Research Report Forced exercise does not improve recovery after hemorrhagic stroke in rats Angela M. Auriat a , Jennifer D. Grams, Reginia H. Yan a , Frederick Colbourne a,b, ⁎ a Department of Psychology, University of Alberta, Edmonton, AB, Canada b Centre for Neuroscience, University of Alberta, Edmonton, AB, Canada ARTICLE INFO ABSTRACT Article history: Accepted 14 June 2006 Available online 18 July 2006 Exercise can improve recovery following ischemia and intracerebral hemorrhage (ICH) in rodents. We tested whether forced exercise (EX; running wheel) prior to and/or following ICH in rats would reduce lesion volume and improve functional outcome (walking, skilled reaching, spontaneous paw usage) at 7 weeks post-ICH. A striatal hemorrhage was produced by infusing collagenase. First, we compared animals that received EX (2 weeks; 1 h/day) ending two days prior to ICH and/or starting two weeks following ICH. EX did not improve functional recovery or affect lesion size. Doubling the amount of EX given per day (two 1-h sessions) both prior to and following ICH did not alter lesion volume, but worsened recovery. We then determined if EX (1 h/day) prior to and following ICH would affect outcome after a somewhat milder insult. There were no differences between the groups in lesion volume or recovery. Finally, we used a hemoglobin assay at 12 h following ICH to determine if pre- stroke EX (2 weeks; 1 h/day) aggravated bleeding. It did not. These observations suggest that EX does not improve outcome when given prior to and/or when delayed following ICH. Effective rehabilitation for ICH will likely require more complex interventions than forced running. © 2006 Elsevier B.V. All rights reserved. Keywords: Intracerebral hemorrhage Striatum Motor system Rehabilitation Stroke 1. Introduction Stroke is one of the leading causes of death and disability in North America. Cerebral bleeding, including intracerebral hemorrhage (ICH), accounts for approximately 15% of all strokes and frequently causes severe disability or death (Mayo et al., 1982). Most experimental and clinical stroke studies focus on finding effective hemostatic or cytopro- tective (neuroprotective) therapies. Furthermore, most stu- dies target cerebral ischemia and not hemorrhagic stroke. Given the differences in pathophysiology (Lipton et al., 1999; Xi et al., 2006), such as the nature of cell death and the extent and location of injury, it is important to test therapies in ICH models as it is possible that treatments that work in ischemia may fail in ICH. This is not only an issue with cytoprotectants, but rehabilitation therapies may also differ in efficacy between ischemic and hemorrhagic events. Various rehabilitation interventions promote recovery after ischemic stroke in rats (e.g., environmental enrich- ment). Interestingly, even simple exercise (EX) treatments such as forced running promote recovery after ischemic stroke, and they also reduce cell death in some situations. For example, Ding and colleagues (2004) found that forced BRAIN RESEARCH 1109 (2006) 183 – 191 ⁎ Corresponding author. P217 Biological Sciences Building, Department of Psychology, University of Alberta, Edmonton, AB, Canada T6G 2E9. Fax: +1 780 492 1768. E-mail address: fcolbour@ualberta.ca (F. Colbourne). 0006-8993/$ – see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.brainres.2006.06.035 available at www.sciencedirect.com www.elsevier.com/locate/brainres