Experimental model of lacunar infarction in the gyrencephalic brain of the miniature pig: neurological assessment and histological, immunohistochemical, and physiological evaluation of dynamic corticospinal tract deformation.
OBJECTIVE
Lacunar infarction accounts for 25% of ischemic strokes, but the pathological characteristics have not been investigated systematically. A new experimental model of lacunar infarction in the miniature pig was developed to investigate the pathophysiological changes in the corticospinal tract from the acute to chronic phases.


METHODS
Thirty-five miniature pigs underwent transcranial surgery for permanent anterior choroidal artery occlusion. Animals recovered for 24 hours (n=7), 2 (n=5), 3 (n=2), 4 (n=2), 6 (n=1), 7 (n=7), 8 (n=2), and 9 days (n=1), 2 weeks (n=2), 4 weeks (n=3), and more than 4 weeks (n=3). Neurology, electrophysiology, histology, and MRI were performed. Seven additional miniature pigs underwent transient anterior choroidal artery occlusion to study muscle motor-evoked potentials and evaluate corticospinal tract function during transient anterior choroidal artery occlusion.


RESULTS
The protocol had a 91.4% success rate in induction of internal capsule infarction 286+/-153 mm(3) (mean+/-SD). Motor-evoked potentials revealed the presence of penumbral tissue in the internal capsule after 6 to 15 minutes anterior choroidal artery occlusion. Total neurological deficit scores of 15.0 (95% CI, 13.5 to 16.4) and 3.4 (0.3 to 6.4) were recorded for permanent anterior choroidal artery occlusion and sham groups, respectively (P<0.001, maximum score 25) with motor deficit scores of 3.4 (95% CI, 2.9 to 4.0) and 0.0 (CI, 0.0 to 0.0), respectively (P<0.001, maximum score 9). Histology revealed that the internal capsule lesion expands gradually from acute to chronic phases.


CONCLUSIONS
This new model of lacunar infarction induces a reproducible infarct in subcortical white matter with a measurable functional deficit and evidence of penumbral tissue acutely.
Department of Neurosurgery, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma 371-8511, Japan.
Yukitaka
Y
Tanaka
Hideaki
H
Imai
Kenjiro
K
Konno
Takaaki
T
Miyagishima
Chisato
C
Kubota
Sandra
S
Puentes
Takeo
T
Aoki
Hidekazu
H
Hata
Kuniaki
K
Takata
Yuhei
Y
Yoshimoto
Nobuhito
N
Saito
D000818:Animals; D001921:Brain / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology; D020520:Brain Infarction / Q000473:pathology* / Q000503:physiopathology*; D004195:Disease Models, Animal; D019054:Evoked Potentials, Motor / Q000502:physiology; D008279:Magnetic Resonance Imaging; D011712:Pyramidal Tracts / Q000473:pathology* / Q000503:physiopathology*; D013552:Swine; D013556:Swine, Miniature