Journal of neurotrauma
-
Journal of neurotrauma · May 2009
The effect of hypothermia on the expression of TIMP-3 after traumatic brain injury in rats.
To investigate the effect of hypothermia on the expression of apoptosis-regulating protein TIMP-3 after fluid percussion traumatic brain injury (TBI) in rats. 210 adult male Sprague Dawley rats were randomly assigned to the groups of TBI with hypothermia treatment (32 degrees C), TBI with normothermia (37 degrees C), and sham injured control. TBI model was induced by fluid percussion TBI device. Mild hypothermia (32 degrees C) was achieved by partial immersion in a water bath (0 degrees C) under general anesthesia for 4 hours. ⋯ In contrast, post-traumatic hypothermia significantly attenuated such an increase. According to the RT-PCR and western blot analysis, the maximum mRNA levels of TIMP-3 were reduced to 60.60%+/-2.30, 55.83%+/-1.80, 66.03%+/-2.10 and 64.51%+/-1.50 of the corresponding values in the normothermic group in injured and uninjured hemispheres (cortex and hippocampus) by hypothermia treatment, respectively (p < 0.01), while the respective maximum protein levels of TIMP-3 were reduced to 57.50%+/-1.50, 52.67%+/-2.20, 60.31%+/-2.50and 54.76%+/-1.40 (p < 0.01). Our data suggests that moderate F-P brain injury would significantly upregulate TIMP-3 expression, while such an increase could be efficiently suppressed by hypothermia treatment.
-
Journal of neurotrauma · May 2009
Reduction of functional brain connectivity in mild traumatic brain injury during working memory.
Working memory deficits are present in patients with mild traumatic brain injury (MTBI). Functional connectivity of different brain regions is required for adequate working memory. Brain injury is associated with disrupted connectivity due to microscopic axonal damage. ⋯ The deficit in coherence was present in theta, alpha, and beta frequency bands. However, the MTBI and the control group had comparable coherence values in intra- and inter-hemispheric regions during eyes closed rest. We suggest that the inter- and intra-hemispheric functional connectivity is impaired in MTBI during working memory performance.
-
Journal of neurotrauma · May 2009
Cerebral autoregulatory response depends on the direction of change in perfusion pressure.
The purpose of cerebral autoregulation is to keep cerebral blood flow constant during variations of cerebral perfusion pressure (CPP). Recently, the autoregulatory response was reported to be greater during arterial blood pressure (ABP) increase than during decrease following repeated induced changes in ABP in 14 brain-injured subjects. The goal of this study was to further investigate the asymmetry of autoregulation during spontaneous increases and decreases of CPP in a larger group of brain injury patients. ⋯ Despite this difference, upMx and downMx were strongly correlated with each other (R=0.82; p < 0.001). In conclusion, the autoregulatory response was significantly greater during increase than during decrease in CPP. The results may indicate non-linear behavior of cerebral autoregulation.
-
Journal of neurotrauma · May 2009
Cerebral hemodynamic predictors of poor 6-month Glasgow Outcome Score in severe pediatric traumatic brain injury.
Little is known regarding the cerebral autoregulation in pediatric traumatic brain injury (TBI). We examined the relationship between cerebral hemodynamic predictors, including cerebral autoregulation, and long-term outcome after severe pediatric TBI. After Institutional Review Board (IRB) approval, a retrospective analysis of prospectively collected data (May 2002 to October 2007) for children age < or =16 years with severe TBI (admission Glasgow Coma Scale [GCS] score <9) was performed. ⋯ Independent risk factors for poor 6-month GOS were impaired cerebral autoregulation (adjusted odds ratio [aOR] 12.0; 95% confidence interval [CI] 1.4-99.4) and hypotension (SBP <5th percentile; aOR 8.8; 95% CI 1.1-70.5), respectively. Previous studies of TBI describing poor outcome with hemodynamics did not consider the status of cerebral autoregulation. In this study, both impaired cerebral autoregulation and SBP <5th percentile were independent risk factors for poor 6-month GOS.
-
Journal of neurotrauma · May 2009
Forced exercise as a rehabilitation strategy after unilateral cervical spinal cord contusion injury.
Evaluation of locomotor training after spinal cord injury (SCI) has primarily focused on hind limb recovery, with evidence of functional and molecular changes in response to exercise. Since trauma at a cervical (C) level is common in human SCI, we used a unilateral C4 contusion injury model in rats to determine whether forced exercise (Ex) would affect spinal cord biochemistry, anatomy, and recovery of fore and hind limb function. SCI was created with the Infinite Horizon spinal cord impactor device at C4 with a force of 200 Kdyne and a mean displacement of 1600-1800 microm in adult female Sprague-Dawley rats that had been acclimated to a motorized exercise wheel apparatus. ⋯ The BBB test showed no change with Ex at the end of the 8-week period, however hind limb grid performance was improved during weeks 2-4. Lesion size was not affected by Ex, but the presence of phagocytic and reactive glial cells was reduced with Ex as an intervention. These results suggest that Ex alone can influence the evolution of the injury and transiently improve fore and hind limb function during weeks 2-4 following a cervical SCI.