Middle cerebral artery occlusion in rats: a neurological and pathological evaluation of a reproducible model.
Middle cerebral artery occlusion (MCAO) in rats produces an infarct of varying size. We examined three factors that may influence this variability: animal weight, vascular anatomy, and extent of occlusion in rats undergoing MCAO. We also developed a four-point neurological evaluation scale and validated its usefulness by comparing it with a four-grade pathological determination of the size of the infarct. Of 82 animals subjected to a standard MCAO, 34 developed small cortical infarcts (pathological grades I-II; infarct size less than 25 mm2, 6-17% of the ipsilateral cortex surface area), and 48 large infarcts (pathological grades III-IV, infarct size greater than 25 mm2, 20-56% of surface area). We were able to predict the size of infarction from the neurological evaluation in 83% of the animals, and this accuracy reached 91% when grades I and II and III and IV were considered together (P less than 0.001). In 41 animals subjected to a more extensive vascular occlusion, 89% exhibited large infarcts. Four vascular patterns were identified but none played a significant role in the incidence or size of the cortical stroke. However, rats weighing less than 300 g showed a smaller lesion size than did rats greater than 300 g. Our proposed new MCAO technique appears useful in reproducing large-sized infarcts of the frontoparietal cortex.
Menzies
S A
SA
Department of Surgery, University of Michigan, Ann Arbor.
Hoff
J T
JT
Betz
A L
AL
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D001921:Brain / Q000473:pathology / Q000503:physiopathology; D002545:Brain Ischemia / Q000473:pathology / Q000503:physiopathology; D001931:Brain Mapping; D002536:Cerebral Arteries / Q000473:pathology / Q000503:physiopathology; D002540:Cerebral Cortex / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology; D002544:Cerebral Infarction / Q000473:pathology / Q000503:physiopathology*; D003097:Collateral Circulation / Q000502:physiology; D004195:Disease Models, Animal; D004292:Dominance, Cerebral / Q000502:physiology; D008297:Male; D009048:Motor Skills / Q000502:physiology; D009460:Neurologic Examination; D051381:Rats; D011919:Rats, Inbred Strains; D012039:Regional Blood Flow / Q000502:physiology; D013239:Stereotyped Behavior / Q000502:physiology