title: Persistent Behavioral Deficits in Rats after Parasagittal Fluid Percussion Injury.
abstract: Although traumatic brain injury (TBI) is now considered a chronic disease, few studies have investigated the long-term behavioral deficits elicited by a well-established rodent model of injury. Here we evaluate behavioral measures, commonly used in TBI research, to determine which tests are useful for studying long-term effects of brain injury in rats. Male Sprague-Dawley rats were handled and pre-trained to neurological, balance, and motor coordination tests prior to receiving parasagittal fluid-percussion injury (FPI), sham injury, or maintenance as naïve cohorts. Rats underwent neuroscore, beam-balance, and beam-walk tests for 3 days after injury. Subsequently, in separate groups at 3, 6, or 12 months, they were re-tested on the same tasks followed by a working memory version of the Morris water maze. On post-injury days (PIDs) 1-3, significant effects of injury on neuroscore, beam-balance, and beam-walk were observed. Differences in the beam-walk task were not detectable at any of the later time-points. However, deficits persisted in beam-balance out to 3 months and neuroscore out to 6 months. Working memory deficits persisted out to 12 months, at which time a reference memory deficit was also evident. These data suggest that balance and motor coordination recovered more quickly than neurological deficits. Furthermore, while deficits in working memory remained stable over the 12-month period, the late onset of the reference memory deficit points to the progressive nature of the injury, or an age/TBI interaction. In conclusion, standard behavioral tests are useful measures of persistent behavioral deficits after parasagittal FPI and provide evidence that TBI is a chronic condition that can change over time and worsen with age.
authors.affiliation: Department of Anesthesiology, University of Texas Medical Branch , Galveston, Texas.
authors.forename: Stacy L
authors.initials: SL
authors.lastname: Sell
authors.affiliation: Department of Anesthesiology, University of Texas Medical Branch , Galveston, Texas.
authors.forename: Kathia
authors.initials: K
authors.lastname: Johnson
authors.affiliation: Department of Anesthesiology, University of Texas Medical Branch , Galveston, Texas.
authors.forename: Douglas S
authors.initials: DS
authors.lastname: DeWitt
authors.affiliation: Department of Anesthesiology, University of Texas Medical Branch , Galveston, Texas.
authors.forename: Donald S
authors.initials: DS
authors.lastname: Prough
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D000070642:Brain Injuries, Traumatic / Q000503:physiopathology*; D002908:Chronic Disease; D004195:Disease Models, Animal; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D009043:Motor Activity / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D065852:Spatial Memory / Q000502:physiology*
keywords: TBI; behavior; chronic brain injury; reference memory; working memory