Evolution of acute focal cerebral ischaemia in rats observed by localized 1H MRS, diffusion-weighted MRI, and electrophysiological monitoring.
Focal cerebral ischaemia was produced in 11 rats by permanent occlusion of the right middle cerebral artery (MCA) using a suture model modified to enable manipulation with the animals in situ in an NMR spectrometer. The development of the ischaemic insults and the resultant infarcts were observed for up to 6 h by localized 1H MRS and diffusion-weighted MRI while performing continuous monitoring of electroencephalogram and extracellular DC potential. The ischaemic areas were depicted as regions of hyperintensity in the diffusion-weighted images. Signals due to lactate became visible in the 1H spectra after MCA occlusion indicating the onset of anaerobic glycolysis. A depletion of N-acetylaspartate was seen in all animals post-occlusion. Transient or stepwise increases of lactate were observed to occur coincidentally with the events of spontaneous transient peri-infarct depolarization detected by the electrophysiological measurements. Expansion of the ischaemic area delineated in the diffusion-weighted images also accompanied peri-infarct depolarizations. These observations are consistent with transient peri-infarct depolarization playing a role in the growth of infarcts.
Gyngell
M L
ML
Max-Planck-Institut für neurologische Forschung, Abteilung für experimentelle Neurologie, Köln, Federal Republic of Germany.
Busch
E
E
Schmitz
B
B
Kohno
K
K
Back
T
T
Hoehn-Berlage
M
M
Hossmann
K A
KA
D000208:Acute Disease; D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000032:analysis; D002545:Brain Ischemia / Q000175:diagnosis* / Q000503:physiopathology; D004569:Electroencephalography; D004594:Electrophysiology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods; D011522:Protons; D051381:Rats; D017208:Rats, Wistar
D011522:Protons; D001224:Aspartic Acid; C000179:N-acetylaspartate