Effects of trauma, hemorrhage and resuscitation in aged rats.

Traumatic brain injury (TBI) is a leading cause of death in the elderly and the incidence of mortality and morbidity increases with age. This study tested the hypothesis that, after TBI followed by hemorrhagic hypotension (HH) and resuscitation, cerebral blood flow (CBF) would decrease more in aged compared with young rats. Young adult (4-6 months) and aged (20-24 months) male Sprague-Dawley rats were anesthetized with isoflurane, prepared for parasagittal fluid percussion injury (FPI) and randomly assigned to receive either moderate FPI (2.

Injured Fluoro-Jade-positive hippocampal neurons contain high levels of zinc after traumatic brain injury.

Hippocampal damage contributes to cognitive dysfunction after traumatic brain injury (TBI). We previously showed that Fluoro-Jade, a fluorescent stain that labels injured, degenerating brain neurons, quantifies the extent of hippocampal injury after experimental fluid percussion TBI in rats. Coincidentally, we observed that injured neurons in the rat hippocampus also stained with Newport Green, a fluorescent dye specific for free ionic zinc.

Dose-dependent neuronal injury after traumatic brain injury.

The Fluoro-Jade (FJ) stain reliably identifies degenerating neurons after multiple mechanisms of brain injury. We modified the FJ staining protocol to quickly stain frozen hippocampal rat brain sections and to permit systematic counts of stained, injured neurons at 4 and 24 h after mild, moderate or severe fluid percussion traumatic brain injury (TBI). In adjacent sections, laser capture microdissection was used to collect uninjured (FJ negative) CA3 hippocampal neurons to assess the effect of injury severity on mRNA levels of selected genes.

Traumatic brain injury and hemorrhagic hypotension suppress neuroprotective gene expression in injured hippocampal neurons.

Background: After traumatic brain injury, memory dysfunction is due in part to damage to the hippocampus. To study the molecular mechanisms of this selective vulnerability, the authors used laser capture microdissection of neurons stained with Fluoro-Jade to directly compare gene expression in injured (Fluoro-Jade-positive) and adjacent uninjured (Fluoro-Jade-negative) rat hippocampal neurons after traumatic brain injury and traumatic brain injury plus hemorrhagic hypotension.

Methods: Twelve isoflurane-anesthetized Sprague-Dawley rats underwent moderate (2.