Delayed treatment with magnesium: reduction of brain infarction and improvement of electrophysiological recovery following transient focal cerebral ischemia in rats.
OBJECTIVE
The authors examined whether delayed treatment with Mg++ would reduce brain infarction and improve electrophysiological and neurobehavioral recovery following cerebral ischemia-reperfusion.


METHODS
Male Sprague-Dawley rats were subjected to right middle cerebral artery occlusion for 90 minutes followed by 72 hours of reperfusion. Magnesium sulfate (750 micromol/kg) or vehicle was given via intracarotid infusion at the beginning of reperfusion. Neurobehavioral outcome and somatosensory evoked potentials (SSEPs) were examined before and 72 hours after ischemia-reperfusion. Brain infarction was assessed after the rats had died. Before ischemia-reperfusion, stable SSEP waveforms were recorded after individual fore- and hindpaw stimulations. At 72 hours of perfusion the SSEPs recorded from ischemic fore- and hindpaw cortical fields were depressed in vehicle-injected animals and the amplitudes decreased to 19 and 27% of baseline, respectively (p < 0.001). Relative to controls, the amplitudes of SSEPs recorded from both ischemic fore- and hindpaw cortical field in the Mg++-treated animals were significantly improved by 23% (p < 0.005) and 39% (p < 0.001) of baselines, respectively. In addition, Mg++ improved sensory and motor neurobehavioral outcomes by 34% (p < 0.01) and 24% (p < 0.05), respectively, and reduced cortical (p < 0.05) and striatal (p < 0.05) infarct sizes by 42 and 36%, respectively.


CONCLUSIONS
Administration of Mg++ at the commencement of reperfusion enhances electrophysiological and neurobehavioral recovery and reduces brain infarction after cerebral ischemia-reperfusion. Because Mg++ has already been used clinically, it may be worthwhile to investigate it further to see if it holds potential benefits for patients with ischemic stroke and for those who will undergo carotid endarterectomy.
Lee
E-Jian
EJ
Neurophysiology Laboratory, Neurosurgical Service, Department of Surgery and Institute of Biomedical Engineering, National Cheng Kung University Medical Center and Medical School, Tainan, Taiwan. ejian@mail.ncku.edu.tw
Lee
Ming-Yang
MY
Chang
Guan-Liang
GL
Chen
Li-Hsuan
LH
Hu
Yu-Ling
YL
Chen
Tsung-Ying
TY
Wu
Tian-Shung
TS
D000818:Animals; D001522:Behavior, Animal; D002540:Cerebral Cortex / Q000473:pathology / Q000503:physiopathology; D003342:Corpus Striatum / Q000473:pathology / Q000503:physiopathology; D005073:Evoked Potentials, Somatosensory; D020244:Infarction, Middle Cerebral Artery / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D007269:Injections, Intra-Arterial; D002546:Ischemic Attack, Transient / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D008274:Magnesium / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D020127:Recovery of Function / Q000187:drug effects*; D020521:Stroke / Q000188:drug therapy / Q000473:pathology / Q000503:physiopathology; D013997:Time Factors
D008274:Magnesium