Substantial Reduction of Parenchymal Cerebral Blood Flow in Mice with Bilateral Common Carotid Artery Stenosis

The bilateral common carotid artery stenosis (BCAS) mouse model, which replicates chronic cerebral hypoperfusion and white matter ischemic lesions, is considered to model some aspects of vascular cognitive impairment. Cerebral blood flow (CBF) changes in the brain surface post-BCAS have been demonstrated by laser speckle flowmetry, but CBF levels in the brain parenchyma remain unknown. Adult C57BL/6J male mice were subjected to BCAS using external microcoils. Brain magnetic resonance angiography (MRA) was conducted to visualize the intracranial main arteries while arterial spin labeling (ASL) was used to measure cortical and subcortical parenchymal CBF levels before and after BCAS. Brain MRA showed anterior circulation flow was substantially decreased until 14 days post-BCAS, which gradually but incompletely recovered over the following 14 days, with probable growth of collaterals from the posterior cerebral artery. ASL showed that cortical and subcortical parenchymal CBF remained decreased at approximately 50% of the baseline level during 1 and 14 days post-BCAS, recovering to approximately 70% at day 28. CBF levels in the parenchyma were lower than the cortical superficial region in the BCAS model and remained decreased without recovery during the first 2 weeks post-BCAS. These results suggest that the BCAS model reliably replicates chronic cerebral hypoperfusion.