Treatment with magnesium improves reference memory but not working memory while reducing GFAP expression following traumatic brain injury

Article type: Research Article

Authors: Hoane, Michael R.

Affiliations: Restorative Neuroscience Laboratory, Brain and Cognitive Science Program, Department of Psychology, Southern Illinois University, Carbondale, IL, USA. Tel.: +618 453 3517; Fax: +618 453 3563; E-mail: [email protected]

Abstract: Purpose: Previous studies have shown that administration of MgCl_{2} in animal models of brain injury significantly improves functional recovery: however, few studies have examined cognitive recovery. The present study evaluated the effect of MgCl_{2} pharmacotherapy on recovery of function following medial frontal cortex contusion injury. Methods: Groups of rats were assigned to either MgCl_{2} (1.0 mmol/kg) or saline treatment conditions and prepared with contusion injuries or shams. Drug treatment was administered 15 min and 24 hr following injury. Rats were examined on tests of sensorimotor performance (bilateral tactile adhesive removal) and cognitive ability (reference and working memory). Results: Administration of MgCl_{2} following injury significantly reduced the behavioral impairments observed on the bilateral tactile removal test. The acquisition of reference memory was also significantly improved compared to saline-treated rats; however, treatment did not improve working memory performance. Lesion analysis revealed that administration of MgCl_{2} did not significantly reduce lesion size compared to saline-treatment. Examination of glial fibrillary acidic protein (GFAP) expression showed that MgCl_{2} did significantly reduce the number of GFAP^+ cells. Conclusion: These results indicate that MgCl_{2} administration significantly improved behavioral outcome following injury in a task dependent manner and reduced GFAP expression.

Keywords: MgCl[TeX:] _{2}, recovery of function, rat, sensorimotor, cognition, neurotrauma, neuroprotection, gliosis

Journal: Restorative Neurology and Neuroscience, vol. 23, no. 2, pp. 67-77, 2005