Affiliations: Department of Emergency Medicine, Brain Research Laboratory, Emory University, Atlanta, Georgia, USA
Correspondence to: Seema Yousuf, Ph.D., Department of Emergency Medicine, Brain Research Laboratory, 1365 B Clifton Road NE, Suite 5100, Emory University, Atlanta, GA 30322, USA. Tel.: +1 404 712 2540; Fax: +1 404 727 2388; firstname.lastname@example.org
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.