title: Concentration of brain free magnesium following severe brain injury correlates with neurologic motor outcome.
abstract: Recent studies have shown that brain intracellular free magnesium concentration significantly declines following mild to severe, focal and diffuse traumatic brain injury. However, little is known about how this decline or its attenuation by magnesium salts relates to neurologic outcome. This study uses phosphorus magnetic resonance spectroscopy and rotarod tests to characterise the relationship between brain free magnesium concentration and neurologic motor scores following severe, diffuse traumatic brain injury in rats. An intravenous bolus of MgSO(4) or MgCl(2) (100 mumoles/kg) at 30 min following brain injury significantly attenuated the postinjury brain free magnesium decline. This improved magnesium homeostasis was sustained for the entire postinjury monitoring period (1 week). There was an associated significant improvement in neurologic motor function in magnesium treated rats. Moreover, the brain free magnesium concentration over the one week period was linearly correlated with the neurologic motor function (r=0.70; P < 0.001) as assessed on a daily basis. We propose that brain free magnesium concentration may be used as a prognostic indicator of neurologic motor function after traumatic brain injury.
authors.affiliation: Department of Physiology and Pharmacology, James Cook University, Townsville, Queensland 4811, Australia.
authors.forename: D L
authors.initials: DL
authors.lastname: Heath
authors.forename: R
authors.initials: R
authors.lastname: Vink