The effects of magnesium sulfate on blood-brain barrier disruption caused by intracarotid injection of hyperosmolar mannitol in rats

Life Sci. 2004 Nov 26;76(2):201-12. doi: 10.1016/j.lfs.2004.07.012.


The study was performed to evaluate whether magnesium sulfate could alter the degree of disruption of the blood-brain barrier (BBB) caused by hyperosmotic mannitol. Wistar adult female rats were infused with 25% mannitol into the left internal carotid artery. Each animal received intraperitoneally a 300 mg/kg loading dose of magnesium sulfate, dissolved in 0.9% saline, followed by a further 100 mg/kg dose. In the other group, intracarotid infusion of magnesium sulfate was performed at a dose of 150 mg/kg 10 min before mannitol administration. Evans blue (EB) dye was used as a marker of BBB disruption. The measured serum glucose and magnesium levels increased after mannitol and/or magnesium administration when compared with their initial values before treatment (P < 0.01). Water content of the left hemisphere was significantly increased by hyperosmotic mannitol (P < 0.01). The increased water content in the mannitol-perfused hemisphere was significantly decreased by magnesium treatment (P < 0.05). The content of EB dye in the mannitol-perfused hemisphere markedly increased when compared with the right hemisphere of the same brain (P < 0.01). The EB dye content in the mannitol-perfused hemisphere following both intraperitoneal and intraarterial administration of magnesium decreased when compared with mannitol alone (P < 0.01). We conclude that although magnesium sulfate administration by both intracarotid arterial and intraperitoneal routes attenuates BBB disruption caused by hyperosmolar mannitol, particularly intraperitoneal route of magnesium sulfate administration may provide a useful strategy to limit the transient osmotic opening of the BBB.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blood Pressure / drug effects
  • Blood-Brain Barrier / drug effects*
  • Brain Edema / chemically induced
  • Brain Edema / prevention & control*
  • Carotid Arteries
  • Diuretics, Osmotic / toxicity*
  • Evans Blue
  • Female
  • Infusions, Intra-Arterial
  • Injections, Intraperitoneal
  • Magnesium Sulfate / pharmacology*
  • Mannitol / toxicity*
  • Osmolar Concentration
  • Rats
  • Rats, Wistar


  • Diuretics, Osmotic
  • Mannitol
  • Evans Blue
  • Magnesium Sulfate