Bilateral Common Carotid Artery Occlusion (BCCAO)-induced Ischemic Stroke causes Cognitive Impairment and Alterations in Histoarchitectural Features of CA1 and CA3 Regions of the Hippocampus

Abstract

A stroke occurs when there is an alteration in the blood circulation within the brain, resulting in neurological impairments. This study aimed to evaluate the cognitive and histological impairment as a result of bilateral common carotid artery occlusion-induced ischemic stroke.Twelve adult male Wistar rats were divided into two groups (n=6); the Control group was only operated on and administered 2 ml/kg distilled H₂O, while the BCCAO/R group was induced with cerebral ischemia by bilateral common carotid artery occlusion and reperfusion (BCCAO/R). Following the induction of ischemic stroke, the Novel Object Recognition (NOR) test was performed to evaluate learning and memory. After experimentation, the animals were anaesthetized with chloral hydrate (350 mg/kg i.p) and euthanatized. The brains were harvested, and the hippocampi were carefully dissected. Homogenates were prepared from half of the disserted hippocampi to assess the specific activity levels of Acetylcholinesterase. The other halves were preserved in 4% paraformaldehyde. The preserved tissues were processed using routine histological procedures and stained with Haematoxylin and Eosin. The result of this study showed a significant decrease in the discrimination ratio and difference score in the BCCAO/R group when compared to the control group during the NOR test. Hippocampal AchE enzyme activity levels increased significantly (P<0.05) in the BCCAO/R group when compared to the control. Histological examination of the CA1 and CA3 regions of the hippocampus in the control group showed normal histoarchitecture of these regions while the BCCAO/R group demonstrated marked neuronal degenerative changes in the CA1 and CA3 regions presenting as karyorrhexis, perineural vacuolation, pyknotic neurons, dark neuron, cytoplasmic vacuolation. BCCAO-induced ischemic stroke induced changes in the cognitive function and histoarchitecture of the CA1 and CA3 regions.