title: Oxidative stress following traumatic brain injury in rats: quantitation of biomarkers and detection of free radical intermediates.
abstract: Oxidative stress may contribute to many pathophysiologic changes that occur after traumatic brain injury. In the current study, contemporary methods of detecting oxidative stress were used in a rodent model of traumatic brain injury. The level of the stable product derived from peroxidation of arachidonyl residues in phospholipids, 8-epi-prostaglandin F(2alpha), was increased at 6 and 24 h after traumatic brain injury. Furthermore, relative amounts of fluorescent end products of lipid peroxidation in brain extracts were increased at 6 and 24 h after trauma compared with sham-operated controls. The total antioxidant reserves of brain homogenates and water-soluble antioxidant reserves as well as tissue concentrations of ascorbate, GSH, and protein sulfhydryls were reduced after traumatic brain injury. A selective inhibitor of cyclooxygenase-2, SC 58125, prevented depletion of ascorbate and thiols, the two major water-soluble antioxidants in traumatized brain. Electron paramagnetic resonance (EPR) spectroscopy of rat cortex homogenates failed to detect any radical adducts with a spin trap, 5,5-dimethyl-1-pyrroline N:-oxide, but did detect ascorbate radical signals. The ascorbate radical EPR signals increased in brain homogenates derived from traumatized brain samples compared with sham-operated controls. These results along with detailed model experiments in vitro indicate that ascorbate is a major antioxidant in brain and that the EPR assay of ascorbate radicals may be used to monitor production of free radicals in brain tissue after traumatic brain injury.
authors.affiliation: Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15238, USA.
authors.forename: V A
authors.initials: VA
authors.lastname: Tyurin
authors.forename: Y Y
authors.initials: YY
authors.lastname: Tyurina
authors.forename: G G
authors.initials: GG
authors.lastname: Borisenko
authors.forename: T V
authors.initials: TV
authors.lastname: Sokolova
authors.forename: V B
authors.initials: VB
authors.lastname: Ritov
authors.forename: P J
authors.initials: PJ
authors.lastname: Quinn
authors.forename: M
authors.initials: M
authors.lastname: Rose
authors.forename: P
authors.initials: P
authors.lastname: Kochanek
authors.forename: S H
authors.initials: SH
authors.lastname: Graham
authors.forename: V E
authors.initials: VE
authors.lastname: Kagan
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001205:Ascorbic Acid / Q000378:metabolism; D015415:Biomarkers / Q000032:analysis; D001923:Brain Chemistry; D001930:Brain Injuries / Q000378:metabolism*; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D051546:Cyclooxygenase 2; D015237:Dinoprost / Q000031:analogs & derivatives* / Q000378:metabolism; D004195:Disease Models, Animal; D004578:Electron Spin Resonance Spectroscopy; D028441:F2-Isoprostanes; D005609:Free Radicals / Q000032:analysis / Q000378:metabolism*; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism; D007527:Isoenzymes / Q000037:antagonists & inhibitors; D008297:Male; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D011451:Prostaglandin-Endoperoxide Synthases; D051381:Rats; D017207:Rats, Sprague-Dawley; D014949:Wounds, Nonpenetrating
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D028441:F2-Isoprostanes; D005609:Free Radicals; D007527:Isoenzymes; C075750:8-epi-prostaglandin F2alpha; D015237:Dinoprost; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D001205:Ascorbic Acid