PURPOSE: Most pre-clinical stroke studies address the acute phase after injury, with less attention to long-term effects of injury, treatment, and experimental testing itself. We addressed these questions: 1) Will functional deficits persist up to 8 weeks following transient stroke in older animals? 2) Will functional deficits resolve spontaneously, with time and/or repeated behavioral testing? METHODS: Male Sprague-Dawley rats (12 months) were pre-trained on behavioral tasks to provide baseline data and then underwent transient middle artery occlusion (tMCAO) or sham surgery. We measured motor, sensory, cognitive and gait impairments over 8 weeks, and the extent of hemispheric brain infarction. One cohort underwent behavioral testing once at 8 weeks post-stroke (LT); a second cohort (RLT) was tested at 3, 6 and 8 weeks post-stroke. RESULTS: Significant deficits were exhibited in all functional outcomes in both cohorts after 8 weeks. We observed some recovery in some behavioral parameters in both cohorts at 8 weeks. CONCLUSIONS: Deficits persist for at least 8 weeks after tMCAO. The greater spontaneous recovery seen in the RLT groups suggest that repeated testing did reduce the severity of these stroke-induced impairments. These findings have implications for designing future studies of agents to induce long-term functional recovery following stroke.
PURPOSE: Most pre-clinical stroke studies address the acute phase after injury, with less attention to long-term effects of injury, treatment, and experimental testing itself. We addressed these questions: 1) Will functional deficits persist up to 8 weeks following transient stroke in older animals? 2) Will functional deficits resolve spontaneously, with time and/or repeated behavioral testing? METHODS: Male Sprague-Dawley rats (12 months) were pre-trained on behavioral tasks to provide baseline data and then underwent transient middle artery occlusion (tMCAO) or sham surgery. We measured motor, sensory, cognitive and gait impairments over 8 weeks, and the extent of hemispheric brain infarction. One cohort underwent behavioral testing once at 8 weeks post-stroke (LT); a second cohort (RLT) was tested at 3, 6 and 8 weeks post-stroke. RESULTS: Significant deficits were exhibited in all functional outcomes in both cohorts after 8 weeks. We observed some recovery in some behavioral parameters in both cohorts at 8 weeks. CONCLUSIONS: Deficits persist for at least 8 weeks after tMCAO. The greater spontaneous recovery seen in the RLT groups suggest that repeated testing did reduce the severity of these stroke-induced impairments. These findings have implications for designing future studies of agents to induce long-term functional recovery following stroke.
Authors: C S Harrell; C Zainaldin; D McFarlane; M M Hyer; D Stein; I Sayeed; G N Neigh Journal: Brain Behav Immun Date: 2018-05-19 Impact factor: 19.227