Occlusion of the MCA by an intraluminal filament may cause disturbances in the hippocampal blood flow due to anomalies of circle of Willis and filament thickness

• Published in: Brain research 1999-03, Vol.822 (1), p.260-264
• Main Authors: Özdemir, Yasemin Gürsoy, Bolay, Hayrunnisa, Erdem, Enis, Dalkara, Turgay
• Format: Article
• Language: English
• Subjects: Animals; Arterial Occlusive Diseases - physiopathology; Biological and medical sciences; Brain Ischemia - physiopathology; Catheterization; Cerebral ischemia; Cerebrovascular Circulation - physiology; Circle of Willis; Circle of Willis - pathology; Circle of Willis - physiology; Disease Models, Animal; Hippocampus; Hippocampus - blood supply; Medical sciences; Mice; Middle cerebral artery occlusion; Mouse; Neurology; Rat; Rats; Rats, Wistar; Vascular diseases and vascular malformations of the nervous system
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/S0006-8993(99)01175-0

We examined blood flow changes and histology in the hippocampus induced by occlusion of the middle cerebral artery (MCA) by a filament in Swiss albino and SV-129 mice ( n=67) and in Wistar rats ( n=64). Filling cerebral arteries with carbon black revealed that one or both posterior communicating arteries were hypoplastic in 50% of Swiss mice. Ischemic changes were detected in the ipsilateral hippocampus with 2,3,5-triphenyl tetrazolium chloride or hematoxylin and eosin staining when these mice were subjected to 2-h MCA occlusion and 22-h reperfusion. No such abnormalities were found in SV-129 mice and Wistar rats (except one). The hippocampal blood flow dropped to 60±2.3% of the baseline in mice with a normal circle of Willis but to 37±4.2% in those with an incomplete circle when the MCA was occluded with a 6/0 nylon filament. When an 8/0 filament was used, no flow change in mice with a normal circle but a decrease to 60±2% in those with an incomplete circle was observed. A flow drop to 63±4% was also seen in Wistar rats when a 3/0 filament used. These data demonstrate that occlusion of the MCA by a thick filament may cause flow reduction in the hippocampus, which may be severe enough to lead to infarction if the circle of Willis is anomalous.