Fluid-Percussion Injury
Objective: To assess hippocampal damage and neuronal vulnerability following traumatic brain injury induced by fluid-percussion impact to the extradural surface of the brain, and to evaluate functional effects on dentate gyrus physiology
Gather these items before starting the experiment. Check off items as you prepare.
Equipment1
Not specified • Not specified • Not specified • Not specified
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Protocol Steps
Administer fluid-percussion injury
Deliver a brief, unilateral fluid-percussion impact to the extradural surface of the brain
Note: Impact is unilateral, affecting one side of the brain
View evidence from paper
“Using a model of fluid-percussion injury, we have discovered that neurons of the dentate hilus are vulnerable to a brief, unilateral impact to the extradural surface of the brain.”
Assess hilar neuron loss at one week post-injury
Examine and quantify reduction in hilar neurons ipsilateral and contralateral to the impact site
Note: Dramatic reduction observed ipsilateral to impact; milder but significant decrease contralateral
View evidence from paper
“One week after trauma, there was a dramatic reduction in hilar neurons ipsilateral to the impact, and a milder but significant decrease in neurons on the contralateral side as well.”
Perform immunocytochemistry
Use immunocytochemistry to identify and assess loss of somatostatin-immunoreactive neurons in the hilar region
Note: Demonstrates selective nature of hilar cell loss
View evidence from paper
“Immunocytochemistry showed that the hilar cell loss included a loss of somatostatin-immunoreactive neurons”
Apply degeneration stains
Use degeneration stains to provide evidence of irreversible hilar injury timing
Note: Irreversible hilar injury occurs within 4 hours of impact
View evidence from paper
“degeneration stains provided evidence that irreversible hilar injury occurred within 4 hr of impact.”
Measure dentate granule cell field potentials
Record dentate granule cell field potentials in response to perforant path stimulation to assess functional effects of hilar damage
Note: Stimulation at 2.0 Hz reveals abnormal hyperexcitability in injured animals
View evidence from paper
“dentate granule cell field potentials were measured in response to perforant path stimulation. This revealed abnormal dentate granule cell hyperexcitability at 2.0 Hz stimulation in many of the injured animals.”