Abstract WMP78: Hypertensive Animals Develop Increased Post-Stroke Cognitive Impairment Associated With Bilateral Enlargement of Brain Ventricles

Abstract

Introduction: Cognitive deficits are a common occurrence in both patients and experimental models of stroke. However, there is still a gap in our understanding of the time course and mechanisms involved in the progression of cognitive dysfunction after stroke in part due to the insufficient integration of risk factors for vascular cognitive impairment such as hypertension. Methods: 50 male rats (26 Wistar and 24 SHR), 14 weeks of age, were subjected to 1 h middle cerebral artery occlusion (MCAO) using a silicone-coated monofilament or sham surgery. Behavioral testing (Bederson, Open Field, Novel Object Recognition, Y-maze, Passive Avoidance and Morris Water Maze) was done (blinded) to examine the progression and resolution of motor and cognitive deficits, weekly for the first 6 weeks post stroke and again at 12 weeks. A brain MRI was done at week 12, animals were sacrificed and brains collected for Western blotting and immunologic staining. Results: Wistar animals showed a high rate of spontaneous recovery 24h after stroke. Both Wistar and SHR animals demonstrated total motor recovery by 2 weeks post stroke. Both groups showed evidence of cognitive dysfunction starting from the 4 th week after stroke. Stroke, especially in the SHR animals, caused a bilateral enlargement of brain ventricles (by MRI) at week 12 suggesting ongoing tissue loss. Conclusions: Normotensive animals show more resilience to the initial insult and a higher rate of 24hr recovery. However, both Wistar and SHR animals show similar patterns in the development and resolution of motor and cognitive impairment. Hypertensive animals showed evidence of an ongoing extensive brain tissue loss up to 3 months after stroke.