A photothrombotic model of small early ischemic infarcts in the rat brain with histologic and MRI correlation.
Over the last two decades several studies have suggested the role of photothrombotic occlusion of cerebral microvessels using rose bengal, resulting in small strokes in rodents that resemble those in humans. This paper describes such a photothrombotic method of acute small stroke induction in rats with histopathologic and in vivo magnetic resonance imaging (MRI) observations from 3 to 6 h after irradiation, which is homologous to a human autopsy specimen. Utilizing 30 min of irradiation with minimal beam intensity (0.1 W/cm(2)) cold white light in conjunction with 20 mg of intravenous (iv) rose bengal as a rapid infusion, small infarcts were induced photochemically in the frontal lobes of six rats. The infarcts showed a consistent pattern on histologic and in vivo MR sections when examined within 7 h or less of irradiation. Both MRI and histologic sections were comprised of (a) a superior zone of infarcted neurons, (b) a middle curvilinear transition zone of edema on MRI and histologically vacuolated neuropil, and (c) an inferior zone of normal neurons. Shorter duration water-sensitive (T2)- and postgadolinium longer duration (T1)-weighted signal decay images both showed a curvilinear hyperintense transition zone of edema. The mean infarct and transition zone areas measured from the histologic sections were comparable to those measured on the MRI. The infarct model described above allows in vivo observations using MRI with the potential for use in testing putative neuroprotective agents. As demonstrated by a comparison with the histologic features of such infarcts in surgical and autopsy brain specimens, the model is relevant to acute human ischemic infarcts.
Pevsner
P H
PH
Department of Pharmacology, New York University School of Medicine, NYU Medical Center, 550 First Ave., New York, New York 10016, USA.
Eichenbaum
J W
JW
Miller
D C
DC
Pivawer
G
G
Eichenbaum
K D
KD
Stern
A
A
Zakian
K L
KL
Koutcher
J A
JA
D000818:Animals; D001921:Brain / Q000098:blood supply / Q000473:pathology* / Q000528:radiation effects; D002544:Cerebral Infarction / Q000209:etiology / Q000473:pathology*; D004195:Disease Models, Animal; D005260:Female; D005456:Fluorescent Dyes; D007091:Image Processing, Computer-Assisted; D007275:Injections, Intravenous; D020767:Intracranial Thrombosis / Q000209:etiology / Q000473:pathology*; D002546:Ischemic Attack, Transient / Q000209:etiology / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008833:Microcirculation / Q000528:radiation effects; D010777:Photochemistry / Q000379:methods*; D011833:Radiation Injuries, Experimental; D051381:Rats; D017207:Rats, Sprague-Dawley; D012395:Rose Bengal / Q000008:administration & dosage
D005456:Fluorescent Dyes; D012395:Rose Bengal