Resuscitation from experimental traumatic brain injury by magnolol therapy.

ABSTRACT

BACKGROUND: The purpose of the present study was to determine whether magnolol, a free radical scavenger, mitigates the deleterious effects of traumatic brain injury (TBI). MATERIAL AND METHODS: Traumatic brain injuries were induced in anesthetized male Sprague-Dawley rats using fluid percussion, and the rats were divided into groups treated with magnolol (2 mg/kg, intravenously) or vehicle. A group of rats that did not undergo TBI induction was also studied as controls. Biomarkers of TBI, including glycerol and 2,3-dihydroxybenzoic acid, were evaluated by microdialysis. Infraction volume, extent of neuronal apoptosis, and antiapoptosis factor transforming growth factor ß1 (TGF-ß1) were also measured. Functional outcomes were assessed by motor assays. RESULTS: Compared with the rats without TBI, the animals with TBI exhibited higher hippocampal glycerol and 2,3-dihydroxybenzoic acid. Relative to the vehicle-treated group, the magnolol-treated group showed decreased hippocampal levels of glycerol and hydroxyl radical levels. The magnolol-treated rats also exhibited decreased cerebral infarction volume and neuronal apoptosis and increased antiapoptosis-associated factor TGF-ß1 expression. These effects were translated into improved motor function post TBI. CONCLUSIONS: Our results suggest that intravenous magnolol injection mitigates the deleterious effects of TBI in rats based on its potent free radical scavenging capability, and the mechanism of anti-neuronal apoptosis is partly due to an increase in TGF-ß1 expression in the ischemic cortex.