title: Effects of magnesium treatment in a model of internal capsule lesion in spontaneously hypertensive rats.
abstract: OBJECTIVE
  The study aim was to assess the effects of magnesium sulfate (MgSO(4)) administration on white matter damage in vivo in spontaneously hypertensive rats.
  
  
  METHODS
  The left internal capsule was lesioned by a local injection of endothelin-1 (ET-1; 200 pmol) in adult spontaneously hypertensive rats. MgSO(4) was administered (300 mg/kg SC) 30 minutes before injection of ET-1, plus 200 mg/kg every hour thereafter for 4 hours. Infarct size was measured by T2-weighted magnetic resonance imaging (day 2) and histology (day 11), and functional recovery was assessed on days 3 and 10 by the cylinder and walking-ladder tests.
  
  
  RESULTS
  ET-1 application induced a small, localized lesion within the internal capsule. Despite reducing blood pressure, MgSO(4) did not significantly influence infarct volume (by magnetic resonance imaging: median, 2.1 mm(3); interquartile range, 1.3 to 3.8, vs 1.6 mm(3) and 1.2 to 2.1, for the vehicle-treated group; by histology: 0.3 mm(3) and 0.2 to 0.9 vs 0.3 mm(3) and 0.2 to 0.5, respectively). Significant forelimb and hindlimb motor deficits were evident in the vehicle-treated group as late as day 10. These impairments were significantly ameliorated by MgSO(4) in both cylinder (left forelimb use, P<0.01 and both-forelimb use, P<0.03 vs vehicle) and walking-ladder (right hindlimb score, P<0.02 vs vehicle) tests.
  
  
  CONCLUSIONS
  ET-1-induced internal capsule ischemia in spontaneously hypertensive rats represents a good model of lacunar infarct with small lesion size, minimal adverse effects, and a measurable motor deficit. Despite inducing mild hypotension, MgSO(4) did not significantly influence infarct size but reduced motor deficits, supporting its potential utility for the treatment of lacunar infarct.
authors.affiliation: 7TMRI Facility, Division of Clinical Neuroscience, University of Glasgow, Garscube Estate, Glasgow G61 1QH, UK.
authors.forename: Clotilde
authors.initials: C
authors.lastname: Lecrux
authors.forename: Christopher
authors.initials: C
authors.lastname: McCabe
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Weir
authors.forename: Lindsay
authors.initials: L
authors.lastname: Gallagher
authors.forename: Jim
authors.initials: J
authors.lastname: Mullin
authors.forename: Omar
authors.initials: O
authors.lastname: Touzani
authors.forename: Keith W
authors.initials: KW
authors.lastname: Muir
authors.forename: Kennedy R
authors.initials: KR
authors.lastname: Lees
authors.forename: I Mhairi
authors.initials: IM
authors.lastname: Macrae
mesh_terms: D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D020520:Brain Infarction / Q000139:chemically induced / Q000188:drug therapy* / Q000473:pathology; D002545:Brain Ischemia / Q000139:chemically induced / Q000188:drug therapy* / Q000473:pathology; D004195:Disease Models, Animal; D019332:Endothelin-1; D006973:Hypertension / Q000150:complications*; D020772:Internal Capsule / Q000187:drug effects* / Q000473:pathology; D008274:Magnesium / Q000097:blood; D008278:Magnesium Sulfate / Q000494:pharmacology*; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009413:Nerve Fibers, Myelinated / Q000187:drug effects / Q000473:pathology; D051381:Rats; D011918:Rats, Inbred SHR; D017207:Rats, Sprague-Dawley
chemical_list: D000927:Anticonvulsants; D019332:Endothelin-1; D008278:Magnesium Sulfate; D008274:Magnesium