Journal of neurotrauma
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Journal of neurotrauma · Jan 2000
Application of 2,3,5-triphenyltetrazolium chloride staining to evaluate injury volume after controlled cortical impact brain injury: role of brain edema in evolution of injury volume.
A reliable method for measuring injury volume after traumatic brain injury (TBI) is of great importance when studying pharmacological protective agents in the field of head trauma research. Utilization of 2,3,5-triphenyltetrazolium chloride (TTC) has gained extensive acceptance in stroke research and has recently been applied to injury volume measurement in the lateral fluid percussion model. The present study was undertaken to apply this method to the controlled cortical impact (CCI) model and to study the role of brain edema. ⋯ A statistically significant reduction of injury volume was observed after postinjury day 4. We also observed that due to the presence of brain edema absolute injury volume is more than corrected injury volume in the first 3 days after injury as opposed to injury volume at postinjury day 7. These results suggest that the measurement of injury volume with TTC staining should be corrected for brain edema in the CCI brain injury model.
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Journal of neurotrauma · Dec 1999
Traumatic brain injury reduces myogenic responses in pressurized rodent middle cerebral arteries.
Traumatic brain injury (TBI) reduces cerebral vascular pressure autoregulation in experimental animals and in patients. In order to understand better the mechanisms of impaired autoregulation, we measured myogenic responses to changes in intraluminal pressure in vitro in pressurized, rodent middle cerebral arteries (MCAs) harvested after TBI. In an approved study, male Sprague-Dawley rats (275-400 g) were anesthetized, intubated, ventilated with 2.0% isoflurane in O2/air, and prepared for fluid percussion TBI. ⋯ In both TBI groups, diameter decreased with each reduction in pressure. In summary, MCAs removed from uninjured, isoflurane-anesthetized rats had normal vasodilatory responses to decreased intraluminal pressure. In contrast, after TBI, myogenic vasodilatory responses were significantly reduced within 5 min of TBI and the impaired myogenic responses persisted for at least 30 min after TBI.
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Journal of neurotrauma · Dec 1999
Chronic and acute compressive spinal cord lesions in dogs due to intervertebral disc herniation are associated with elevation in lumbar cerebrospinal fluid glutamate concentration.
Acute injury to the central nervous system initiates a series of biochemical events that cause secondary tissue damage. The accumulation of excessive concentrations of glutamate in the extracellular space causes excitotoxic damage, and is incriminated as a mediator of this secondary tissue damage. The aim of this study was to measure the concentration of glutamate in cerebrospinal fluid (CSF) obtained from the cerebellomedullary cistern and lumbar subarachnoid space in dogs with acute and chronic compressive injuries of the cervical and thoracolumbar spinal cord, and to correlate the glutamate concentration with injury severity. ⋯ However, dogs with severe, acute thoracolumbar disc herniations have two- to 10-fold increases in glutamate concentration in their lumbar CSF at intervals of >12 h after injury. Moreover, the severity of their clinical signs is directly related to the glutamate concentration. Dogs with chronic compressive thoracolumbar lesions have a two-fold elevation of CSF glutamate concentration, suggesting that excitotoxicity may also be a component of chronic spinal cord compression.
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Journal of neurotrauma · Dec 1999
Interrelations of laser doppler flowmetry and brain tissue oxygen pressure during ischemia and reperfusion induced by an experimental mass lesion.
The objective of this study was to assess interrelations between bilateral changes of cortical laser doppler flowmetry and intraparenchymal, subcortical partial tissue oxygen tension in the course of an experimental trauma. Ten animals served as a sham group, 8 Sprague-Dawley rats received an unilateral, focal parietal mass lesion. The bilateral course of cortical blood flow measured by laser doppler flowmetry (LDF) was correlated with subcortical, intraparenchymal partial tissue oxygen tension [p(ti)O2]. ⋯ Both parameters showed a significant but rather weak correlation (r = 0.56; p < 0.001). Based upon these findings, we conclude that intraparenchymal, subcortical p(ti)O2 measurements supplemented on-line cortical CBF monitoring and score out discontinuous alternative measurement techniques in detecting hemodynamically relevant events. The small spatial resolution of LDF and p(ti)O2 probes, however, which in the small animal model may be of negligible influence, does raise the question whether the values obtained represent the microcirculatory situation of the human brain.
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Journal of neurotrauma · Oct 1999
Systemically administered interleukin-10 reduces tumor necrosis factor-alpha production and significantly improves functional recovery following traumatic spinal cord injury in rats.
In these studies, we examined the neuroprotective effects of the potent antiinflammatory cytokine interleukin-10 (IL-10) following spinal cord injury (SCI). Neuroprotection was assessed by using behavioral and morphological end points. We hypothesized that injury-induced inflammation contributes to the resulting neuropathology and subsequent loss of function. ⋯ IL-10-treated animals had a mean BBB score of 18.0+/-0.5 (SEM, n = 9) compared with a score of 12.9+/-0.6 (SEM, n = 9) for the saline-treated controls. Morphological analysis demonstrated that IL-10 reduces lesion volume by approximately 49% 2 months after injury. These data suggest that acute administration of IL-10 reduces TNF-alpha synthesis in the spinal cord and by activated macrophages, is neuroprotective, and promotes functional recovery following SCI.