New insights into brain damage in stroke-prone rats: a nuclear magnetic imaging study.
OBJECTIVE
The spontaneously hypertensive stroke-prone rat (SHRSP) is an animal model for a complex form of cerebrovascular pathology. MRI provides an efficient and noninvasive tool for studying the time course of brain damage. The aim of this study was to gain new insights into the pathological phenomena responsible for the occurrence of brain injury in SHRSP with the use of the apparent diffusion coefficient of water (ADC), one of the most efficient MRI parameters for detecting brain abnormalities. To this end, the pattern of ADC variation observed in SHRSP was compared with that of focal ischemia induced in both SHRSP and Sprague-Dawley rats.


METHODS
Four groups of animals were studied: SHRSP developing spontaneous brain lesions fed with a salt-loaded (n=15, group 1) or standard diet (n=3, group 2) and Sprague-Dawley rats (n=8, group 3) and SHRSP (n=8, group 4) with permanent middle cerebral artery occlusion. ADC maps and T2-weighted images of brains were performed by MRI. After the rats were killed, the brains were removed and histologically processed.


RESULTS
There was no decrease in ADC during spontaneous stroke in the SHRSP fed with a normal or salt-enriched diet, while both the SHRSP and Sprague-Dawley rats with middle cerebral artery occlusion showed a marked decrease that lasted for 24 to 48 hours.


CONCLUSIONS
Cerebral ischemia cannot be considered a major factor in the onset of spontaneous brain lesions in SHRSP, which show only vasogenic edema after the beginning of the damage with no evidence of metabolic impairment.
Guerrini
Uliano
U
Department of Pharmacological Sciences, University of Milan, Italy
Sironi
Luigi
L
Tremoli
Elena
E
Cimino
Mauro
M
Pollo
Bianca
B
Calvio
Anna Maria
AM
Paoletti
Rodolfo
R
Asdente
Maria
M
D000818:Animals; D001929:Brain Edema / Q000175:diagnosis / Q000209:etiology / Q000473:pathology; D004058:Diffusion; D018450:Disease Progression; D020244:Infarction, Middle Cerebral Artery / Q000150:complications; D008279:Magnetic Resonance Imaging; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR; D017207:Rats, Sprague-Dawley; D012982:Sodium, Dietary / Q000009:adverse effects; D020521:Stroke / Q000175:diagnosis* / Q000209:etiology / Q000473:pathology*
D012982:Sodium, Dietary