title: Acute White Matter Tract Damage after Frontal Mild Traumatic Brain Injury.
abstract: Our understanding of mild traumatic brain injury (mTBI) is still in its infancy and to gain a greater understanding, relevant animal models should replicate many of the features seen in human mTBI. These include changes to diffusion tensor imaging (DTI) parameters, absence of anatomical lesions on conventional neuroimaging, and neurobehavioral deficits. The Maryland closed head TBI model causes anterior-posterior plus sagittal rotational acceleration of the brain, frequently observed with motor vehicle and sports-related TBI injuries. The injury reflects a concussive injury model without skull fracture. The goal of our study was to characterize the acute (72 h) pathophysiological changes occurring following a single mTBI using magnetic resonance imaging (MRI), behavioral assays, and histology. We assessed changes in fractional anisotropy (FA), mean (MD), longitudinal (LD), and radial (RD) diffusivities relative to pre-injury baseline measures. Significant differences were observed in both the longitudinal and radial diffusivities in the fimbria compared with baseline. A significant difference in radial diffusivity was also observed in the splenium of the corpus callosum compared with baseline. The exploratory activity of the mTBI animals was also assessed using computerized activity monitoring. A significant decrease was observed in ambulatory distance, average velocity, stereotypic counts, and vertical counts compared with baseline. Histological examination of the mTBI brain sections indicated a significant decrease in the expression of myelin basic protein in the fimbria, splenium, and internal capsule. Our findings demonstrate the vulnerability of the white matter tracts, specifically the fimbria and splenium, and the ability of DTI to identify changes to the integrity of the white matter tracts following mTBI.
authors.affiliation: 1 Department of Diagnostic and Interventional Imaging, The University of Texas Health Science Center at Houston (UTHealth) , McGovern Medical School, Houston, Texas.
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Herrera
authors.affiliation: 1 Department of Diagnostic and Interventional Imaging, The University of Texas Health Science Center at Houston (UTHealth) , McGovern Medical School, Houston, Texas.
authors.forename: Kurt
authors.initials: K
authors.lastname: Bockhorst
authors.affiliation: 1 Department of Diagnostic and Interventional Imaging, The University of Texas Health Science Center at Houston (UTHealth) , McGovern Medical School, Houston, Texas.
authors.forename: Shakuntala
authors.initials: S
authors.lastname: Kondraganti
authors.affiliation: 2 Translational Psychiatry Program, Department of Psychiatry and Behavioral Sciences, The University of Texas Health Science Center at Houston (UTHealth) , McGovern Medical School, Houston, Texas.
authors.forename: Laura
authors.initials: L
authors.lastname: Stertz
authors.affiliation: 2 Translational Psychiatry Program, Department of Psychiatry and Behavioral Sciences, The University of Texas Health Science Center at Houston (UTHealth) , McGovern Medical School, Houston, Texas.|3 Center of Excellence on Mood Disorders, Department of Psychiatry and Behavioral Sciences, The University of Texas Health Science Center at Houston (UTHealth) , McGovern Medical School, Houston, Texas.
authors.forename: João
authors.initials: J
authors.lastname: Quevedo
authors.affiliation: 1 Department of Diagnostic and Interventional Imaging, The University of Texas Health Science Center at Houston (UTHealth) , McGovern Medical School, Houston, Texas.
authors.forename: Ponnada A
authors.initials: PA
authors.lastname: Narayana
mesh_terms: D000818:Animals; D001924:Brain Concussion / Q000000981:diagnostic imaging* / Q000378:metabolism; D056324:Diffusion Tensor Imaging / Q000379:methods; D005106:Exploratory Behavior / Q000502:physiology; D005625:Frontal Lobe / Q000000981:diagnostic imaging* / Q000378:metabolism; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D066127:White Matter / Q000000981:diagnostic imaging* / Q000378:metabolism
keywords: MRI behavioral assessments; diffusion tensor imaging; inflammation; mild traumatic brain injury