Citation

Hylin MJ, Orsi SA, Zhao J, Bockhorst KH, Perez AI, Moore AN, Dash PK. J. Neurotrauma 2013; 30(9): 702-715.

Affiliation

University of Texas Health Science Center-Houston, Neurobiology and Anatomy, 6431 Fannin, Houston, Texas, United States, 77030; michael.j.hylin@uth.tmc.edu.

Copyright

(Copyright © 2013, Mary Ann Liebert Publishers)

DOI

10.1089/neu.2012.2630

PMID

23301501

Abstract

The majority of people who sustain a traumatic brain injury (TBI) have an injury that can be classified as mild (often referred to as concussion). Although head CT scans for most subjects who have sustained a mild TBI (mTBI) are negative, these persons may still suffer from neurocognitive and neurobehavioral deficits. In order to expedite pre-clinical research and develop therapies, there is a need for well characterized animal models of mTBI that reflect the neurological, neurocognitive and pathological changes seen in human patients. In the present study, we examined the motor, cognitive and histopathological changes resulting from 1.0 and 1.5 atmosphere (atm) overpressure fluid percussion injury (FPI). Both 1.0 and 1.5atm FPI injury caused transient suppression of acute neurological functions, but did not result in visible brain contusion. Animals injured with 1.0atm FPI did not show significant motor, vestibulomotor or learning and memory deficits. In contrast, 1.5atm injury caused transient motor disturbances, and resulted in a significant impairment of spatial learning and short-term memory. In addition, 1.5atm FPI caused a marked reduction in cerebral perfusion at the site of injury that lasted for several hours. Consistent with previous studies, 1.5atm FPI did not cause visible neuronal loss in the hippocampus or in the neocortex. However, a robust inflammatory response (as indicated by enhanced GFAP and Iba1 immunoreactivity) in the corpus callosum and the thalamus was observed. Examination of fractional anisotropy color maps after diffusion tensor imaging (DTI) revealed a significant decrease of FA values in the cingulum, an area found to have increased silver impregnation, suggesting axonal injury. Increased silver impregnation was also observed in the corpus callosum, and internal and external capsules. These findings are consistent with the deficits and pathologies associated with mild TBI in humans, and support the use of mild FPI as a model to evaluate putative therapeutic options.

Language: en