Mild experimental brain injury in the rat induces cognitive deficits associated with regional neuronal loss in the hippocampus.
Memory dysfunction following mild human traumatic brain injury (TBI) is a common clinical observation, but the pathologic substrate underlying this loss of function has not been well-characterized. In the present study, we examined the effects of a mild lateral fluid percussion (FP) brain injury on memory dysfunction, neuronal cell loss in specific regions of the hippocampus, and breakdown of the blood-brain barrier (BBB). A Morris Water Maze (MWM) memory paradigm was used to assess memory retention in rats 42 h after lateral FP brain injury (n = 11) or sham injury (n = 10). At the completion of cognitive testing, animals were sacrificed and neuronal cell loss in the hippocampi was examined with Nissl staining. Immunoreactivity to anti-rat IgG was used to evaluate the extent of BBB disruption. A significant correlation was observed between posttraumatic memory scores and neuronal loss in the hilus of the dentate gyrus (p < 0.005). To our knowledge, these observations are the first to suggest an association between cognitive deficits following a mild experimental brain injury and neuropathological changes in the hippocampus.
Hicks
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Department of Anatomy, University of Connecticut Health Center, Farmington.
Smith
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Lowenstein
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Saint Marie
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McIntosh
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D000818:Animals; D001784:Blood Gas Analysis; D001812:Blood-Brain Barrier / Q000502:physiology; D001924:Brain Concussion / Q000150:complications / Q000473:pathology* / Q000523:psychology*; D002540:Cerebral Cortex / Q000473:pathology; D003072:Cognition Disorders / Q000209:etiology / Q000523:psychology*; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology; D006624:Hippocampus / Q000473:pathology*; D007150:Immunohistochemistry; D008297:Male; D008568:Memory / Q000502:physiology; D009410:Nerve Degeneration / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D017966:Pyramidal Cells / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012044:Regression Analysis