Neurological dysfunctions versus regional infarction volume after focal ischemia in Mongolian gerbils.
OBJECTIVE
With advances in the therapy of stroke at the postacute phase, the use of animal models for chronological and region-specific evaluation of neurological function has become increasingly important. Our aim was to test long-term behavioral dysfunction in gerbils after focal ischemia and to correlate the results with the regional distribution of infarction in the coordinating cortical regions.


METHODS
Repetitive unilateral hemispheric ischemia (two 10-minute occlusions, 5-hour interval) was induced in Mongolian gerbils. The elevated body swing test (EBST), bilateral asymmetry test (BAT), and T-maze test were performed to assess asymmetrical motor behavior, somatosensory deficit, and spatial cognitive dysfunction during 4 weeks after ischemia. The results were correlated against the regional infarction volume of the primary motor, somatosensory, and primary visual cortices at 4 weeks after ischemia.


RESULTS
In all postischemic gerbils, persistent sensorimotor and cognitive dysfunctions were detectable throughout the postischemic period. Histological examination revealed that a cortical zone of infarction surrounded the selective neuronal death in the ipsilateral cerebral hemisphere. The regional infarction volumes of the primary motor, somatosensory, and visual cortices were significantly correlated with the scores of the EBST, BAT, and T-maze test, respectively. These combinations had the highest regression coefficient of all pairs.


CONCLUSIONS
Postischemic motor and somatosensory functions were significantly correlated with regional infarction volumes in the corresponding cortical regions. In gerbils, visual abnormality could be independently detected by the T-maze test. Such regional analyses of ischemic lesions would be useful for investigating the functional outcomes of stroke therapy.
Department of Neurology and Neurological Science, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan.
Satoru
S
Ishibashi
Toshihiko
T
Kuroiwa
Shu
S
Endo
Riki
R
Okeda
Hidehiro
H
Mizusawa
D000818:Animals; D001522:Behavior, Animal; D001921:Brain / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology; D002545:Brain Ischemia / Q000150:complications / Q000503:physiopathology*; D017536:Carotid Artery, Common / Q000502:physiology; D002544:Cerebral Infarction / Q000209:etiology / Q000473:pathology*; D003072:Cognition Disorders / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D004195:Disease Models, Animal; D018450:Disease Progression; D005260:Female; D005849:Gerbillinae; D008297:Male; D018782:Maze Learning; D009043:Motor Activity; D009422:Nervous System Diseases / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D012720:Severity of Illness Index; D013995:Time; D014786:Vision Disorders / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology