Journal of neurotrauma
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Journal of neurotrauma · Oct 2009
Activity-based therapies to promote forelimb use after a cervical spinal cord injury.
Significant interest exists in strategies for improving forelimb function following spinal cord injury. We investigated the effect of enriched housing combined with skilled training on the recovery of skilled and automatic forelimb function after a cervical spinal cord injury in adult rats. All animals were pretrained in skilled reaching, gridwalk crossing, and overground locomotion. ⋯ Both enriched housing and rolipram increased plasticity of the corticospinal tract rostral to the lesion. These studies indicate that skilled training after a cervical spinal cord injury improves recovery of skilled forelimb use (reaching) and coordinated limb function (gridwalk) but does not improve automatic forelimb function (locomotion and vertical exploration). These studies suggest that rehabilitating forelimb function after spinal cord injury will require separate strategies for descending and segmental pathways.
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Journal of neurotrauma · Oct 2009
Electrical stimulation accelerates motor functional recovery in autograft-repaired 10 mm femoral nerve gap in rats.
Electrical stimulation has been shown to enhance peripheral nerve regeneration after nerve injury. However, the impact of electrical stimulation on motor functional recovery after nerve injuries, especially over long nerve gap lesions, has not been investigated in a comprehensive manner. In the present study, we aimed to determine whether electrical stimulation (1 h, 20 Hz) is beneficial for motor functional recovery after a 10 mm femoral nerve gap lesion in rats. ⋯ The rate of motor functional recovery was evaluated by single frame motion analysis and electrophysiological studies, and the nerve regeneration was investigated by double labeling and histological analysis. We found that brief electrical stimulation significantly accelerated motor functional recovery and nerve regeneration. Although the final outcome, both in functional terms and morphological terms, was not improved by electrical stimulation, the observed acceleration of functional recovery and axon regeneration may be of therapeutic importance in clinical setting.
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Journal of neurotrauma · Oct 2009
Serial changes in bladder, locomotion, and levels of neurotrophic factors in rats with spinal cord contusion.
The aims of this study were to evaluate the evolution of the neurogenic bladder after spinal cord contusion and to correlate changes in bladder function with locomotor function and levels of neurotrophic factors. The MASCIS impactor was used to cause a mild contusion injury of the lower thoracic spinal cord of Sprague-Dawley rats. Rats were divided into four groups according to the length of time from injury to sacrifice, at 4, 14, 28, and 56 days after injury. ⋯ Brain-derived neurotrophic factor (BDNF) levels in the spinal cord, as detected by enzyme-linked immunosorbent assay, decreased with time, whereas neurotrophin-3 (NT-3) levels remained unchanged. The micturition pattern, bladder volume, and locomotor function continued to recover during the time of observation; BDNF levels in the spinal cord and bladder were inversely correlated with BBB scores and the restoration of bladder volume. We conclude that urodynamic changes in the bladder correlate with locomotion recovery but not with the levels of BDNF or NT-3 after modified mild contusion injury in rats.
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Journal of neurotrauma · Oct 2009
Heat stress preconditioning improves cognitive outcome after diffuse axonal injury in rats.
This study investigates the influence of heat stress preconditioning on cognitive outcome for rats with diffuse axonal injury (DAI), and attempts to examine the underlying mechanisms. Wistar rats were divided into four groups: rats subjected to heat stress preconditioning 24 h before induction of DAI (n = 10; HSDAI group), a DAI alone group (n = 10), a heat stress alone group (n = 10), and a sham-injury group (n = 10). From day 14 post-injury, the rats' learning abilities and memory were tested using the Morris water maze (MWM) task, followed by long-term potentiation (LTP) recording of the hippocampus. ⋯ Following injury, retraction balls, shrunken neurons, and HSP70 expression were visible in the brains of rats from the DAI and HSDAI groups; recovery was expedited in the rats belonging to the HSDAI group, as these pathological changes were alleviated, coincident with higher expression of HSP70. The rats' abilities for learning and memory were impaired following DAI; this may be due to the disconnection of brain regions, damage to neurons in the hippocampus, and a decrease in synaptic plasticity. Heat stress preconditioning is able to significantly attenuate this cognitive impairment, possibly mediated by the neuroprotective effect of HSP70.
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Journal of neurotrauma · Sep 2009
The persistent effects of concussion on neuroelectric indices of attention.
Mild traumatic brain injuries (mTBIs) that result from participation in sports are a major public health issue affecting 1.6-3.8 million individuals annually. The injury has been postulated as transient and void of long-term consequences when rapidly diagnosed and properly managed. Emerging evidence, however, has suggested an increased risk for late life cognitive dysfunction in those with previous injuries. ⋯ Significant decrements in the N2 and P3b amplitudes of the stimulus-locked ERP were noted for those with a history relative to those without a history of concussion. Although the previously concussed participants performed equal to those without injury on the clinical cognitive assessment, these findings support the notion that sport mTBI can no longer be thought of as a transient injury resulting in short-lived neurological impairment. It is not clear if these persistent deficits will manifest into clinical pathologies later in life.