title: Temporal and regional changes after focal traumatic brain injury.
abstract: Magnetic resonance imaging (MRI) is widely used to evaluate the consequences of traumatic brain injury (TBI) in both experimental and clinical studies. Improved assessment of experimental TBI using the same methods as those used in clinical investigations would help to translate laboratory research into clinical advances. Here our goal was to characterize lateral fluid percussion-induced TBI, with special emphasis on differentiating the contused cortex from the pericontusional subcortical tissue. We used both in vivo MRI and proton magnetic resonance spectroscopy ((1)H-MRS) to evaluate adult male Sprague-Dawley rats 24 h and 48 h and 7 days after TBI. T2 and apparent diffusion coefficient (ADC) maps were derived from T2-weighted and diffusion-weighted images, respectively. Ratios of N-acetylaspartate (NAA), choline compounds (Cho), and lactate (Lac) over creatine (Cr) were estimated by (1)H-MRS. T2 values were high in the contused cortex 24 h after TBI, suggesting edema development; ADC was low, consistent with cytotoxic edema. At the same site, NAA/Cr was decreased and Lac/Cr elevated during the first week after TBI. In the ipsilateral subcortical area, NAA/Cr was markedly decreased and Lac/Cr was elevated during the first week, although MRI showed no evidence of edema, suggesting that (1)H-MRS detected "invisible" damage. (1)H-MRS combined with MRI may improve the detection of brain injury. Extensive assessments of animal models may increase the chances of developing successful neuroprotective strategies.
authors.affiliation: Equipe de recherche Pharmacologie de la Circulation Cérébrale (EA 2510), Faculté des Sciences Pharmaceutiques et Biologiques, Université Paris Descartes, Paris, France. thomas.lescot@psl.aphp.fr
authors.forename: Thomas
authors.initials: T
authors.lastname: Lescot
authors.forename: Laurence
authors.initials: L
authors.lastname: Fulla-Oller
authors.forename: Lawrence
authors.initials: L
authors.lastname: Fulla-Oller
authors.forename: Chrystelle
authors.initials: C
authors.lastname: Po
authors.forename: Xiao Ru
authors.initials: XR
authors.lastname: Chen
authors.forename: Louis
authors.initials: L
authors.lastname: Puybasset
authors.forename: Brigitte
authors.initials: B
authors.lastname: Gillet
authors.forename: Michel
authors.initials: M
authors.lastname: Plotkine
authors.forename: Philippe
authors.initials: P
authors.lastname: Meric
authors.forename: Catherine
authors.initials: C
authors.lastname: Marchand-Leroux
mesh_terms: D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D001921:Brain / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology*; D001929:Brain Edema / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D001930:Brain Injuries / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D002794:Choline / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D004058:Diffusion; D004195:Disease Models, Animal; D019344:Lactic Acid / Q000378:metabolism; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
chemical_list: D001224:Aspartic Acid; D019344:Lactic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline