Middle cerebral artery occlusion in the rat by intraluminal suture. Neurological and pathological evaluation of an improved model.
OBJECTIVE
The purpose of the present study was to evaluate a modified method of intraluminal suture occlusion of the middle cerebral artery (MCA) on the volume of brain infarction and on neurobehavioral function in rats subjected to a temporary focal ischemic insult.


METHODS
Male Sprague-Dawley rats were anesthetized with halothane and subjected to 60 minutes or 2 hours of temporary MCA occlusion (MCAo) by an intraluminal thread. In one group of rats, the suture was coated with poly-L-lysine, while in a second group, a conventional uncoated suture was used. Behavioral function was evaluated at 50 to 60 minutes after occlusion and during a 3-day period after MCAo. Three days after MCAo brains were perfusion-fixed and infarct volumes were measured.


RESULTS
In rats with 60-minute MCAo, only 3 of 7 animals with uncoated sutures had infarcts, whereas in the group with poly-L-lysine-coated sutures, all rats (n = 7) exhibited infarction (P = .009, Fisher's exact test). With 2 hours of MCAo, total infarct volume (corrected for brain edema) was significantly larger in rats with poly-L-lysine-coated sutures than in the group with uncoated sutures (mean +/- SEM, 122.1 +/- 4.8 versus 67.0 +/- 18.2 mm3, respectively; P = .03; n = 4 in each group). In the 2-hour MCAo study, infarct volumes in the uncoated-suture group tended to be variable and inconsistent (coefficient of variation, 54%) compared with the group in which sutures were coated with poly-L-lysine, in which a highly consistent infarct was produced (coefficient of variation of infarct volume, 8%).


CONCLUSIONS
Reversible MCAo in which a poly-L-lysine-coated intraluminal suture was used proved to be a reliable and effective modification of this technique, yielding consistently larger infarcts and greatly reduced interanimal variability.
Belayev
L
L
Department of Neurology, University of Miami School of Medicine, FL 33101, USA.
Alonso
O F
OF
Busto
R
R
Zhao
W
W
Ginsberg
M D
MD
D000818:Animals; D001157:Arterial Occlusive Diseases / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology*; D001522:Behavior, Animal / Q000502:physiology; D001921:Brain / Q000473:pathology; D002536:Cerebral Arteries; D002544:Cerebral Infarction / Q000473:pathology / Q000503:physiopathology; D008297:Male; D009420:Nervous System / Q000503:physiopathology*; D011107:Polylysine; D051381:Rats; D017207:Rats, Sprague-Dawley; D013499:Surface Properties; D013536:Suture Techniques; D013537:Sutures
D011107:Polylysine