Official websites use. Share sensitive information only on official, secure websites. Address correspondence to: Wendy Murdock Reid, Ph. E-mail: murdockwm vcu. The present study directly compares the effects of experimental brain injury in two commonly used rat strains: Fisher and Sprague-Dawley. We previously found that Fisher rats have a higher mortality rate and more frequent seizure attacks at the same injury level than Sprague-Dawley rats. Although strain differences in rats are commonly accepted as contributing to variability among studies, there is a paucity of literature addressing strain influence in experimental neurotrauma.
Therefore this study compares outcome measures in two rat strains following lateral fluid percussion injury. Fisher and Sprague-Dawley rats were monitored for changes in physiological measurements, intracranial pressure, and electroencephalographic activity. We further analyzed neuronal degeneration and cell death in the injured brain using Fluoro-Jade-B FJB histochemistry and caspase-3 immunostaining.
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Behavioral studies using the beam walk and Morris water maze were conducted to characterize strain differences in both motor and cognitive functional recovery following injury. We found that Fisher rats had significantly higher intracranial pressure, prolonged seizure activity, increased FJB-positive staining in the injured cortex and thalamus, and increased caspase-3 expression than Sprague-Dawley rats.
On average, Fisher rats displayed a greater amount of total recording time in seizure activity and had longer ictal durations. The Fisher rats also had increased motor deficits, correlating with the above results. In spite of these results, Fisher rats performed better on cognitive tests following injury. The results demonstrate that different rat strains respond to injury differently, and thus in preclinical neurotrauma studies strain influence is an important consideration when evaluating outcomes.
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Key words: epilepsy, Fischer rat, fluid percussion injury, Sprague-Dawley rat, strain. T he heterogeneity of traumatic brain injury TBI has been difficult to replicate in standardized animal models of TBI that strive for less variability in experimental conditions. Several experimental TBI models have been developed to replicate the various pathoanatomical conditions observed clinically, and to test therapeutic interventions.
