Complications and pitfalls in rat stroke models for middle cerebral artery occlusion: a comparison between the suture and the macrosphere model using magnetic resonance angiography.
OBJECTIVE
Investigating focal cerebral ischemia requires animal models that are relevant to human stroke. Complications and side effects are common among these models. The present study describes potential pitfalls in 3 techniques for middle cerebral artery occlusion (MCAO) in rats using magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA).


METHODS
Rats were subjected to temporary MCAO for 90 minutes using the suture technique (group I; n=10) or to permanent MCAO using the suture technique (group II; n=10) or the macrosphere technique (group III; n=10). Clinical evaluation was performed after 3 hours and 24 hours. After 24 hours, animals underwent MRI and MRA to determine lesion size and the intracranial vascular status.


RESULTS
Hemispheric lesion volume was significantly smaller in group I (14.6%) compared with groups II (35.2%; P<0.01) and III (21.3%; P<0.05). Two animals (1 each in group II and III) did not demonstrate neurological deficits and had no lesion on MRI and a patent MCA main stem on MRA. Subarachnoid hemorrhage was detected in 2 animals (1 each in group I and II). MRA indicated a patent MCA main stem in 2 animals (group II), although both rats displayed neurological deficits. Hypothalamic infarction with subsequent pathological hyperthermia was detected in all animals in group II and in 1 rat in group III.


CONCLUSIONS
Model failures occurred frequently in all groups. MRI and MRA helps to identify animals that need to be excluded from experimental stroke studies.
Gerriets
Tibo
T
Department of Radiology, Experimental Neurology Research Group, Kerckhoff-Klinik Bad Nauheim, Germany.
Stolz
Erwin
E
Walberer
Maureen
M
Müller
Clemens
C
Rottger
Carina
C
Kluge
Alexander
A
Kaps
Manfred
M
Fisher
Marc
M
Bachmann
Georg
G
D000818:Animals; D002342:Carotid Artery, External; D004195:Disease Models, Animal; D020244:Infarction, Middle Cerebral Artery; D008026:Ligation; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging; D008297:Male; D008863:Microspheres; D051381:Rats; D017207:Rats, Sprague-Dawley; D013536:Suture Techniques; D014025:Titanium
C009495:titanium dioxide; D014025:Titanium