Journal of neurotrauma
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Journal of neurotrauma · May 2013
Consequences of common data analysis inaccuracies in CNS trauma injury basic research.
The development of successful treatments for humans after traumatic brain or spinal cord injuries (TBI and SCI, respectively) requires animal research. This effort can be hampered when promising experimental results cannot be replicated because of incorrect data analysis procedures. To identify and hopefully avoid these errors in future studies, the articles in seven journals with the highest number of basic science central nervous system TBI and SCI animal research studies published in 2010 (N=125 articles) were reviewed for their data analysis procedures. ⋯ Reanalysis of our published data using the most common inappropriate statistical procedures resulted in a 14.1% average increase in significant effects compared to the original results. Specifically, an increase of 15.5% occurred with Independent t-tests and 11.1% after incorrect post hoc t-tests. Utilizing proper statistical procedures can allow more-definitive conclusions, facilitate replicability of research results, and enable more accurate translation of those results to the clinic.
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Journal of neurotrauma · May 2013
Chronic at- and below-level pain after moderate unilateral cervical spinal cord contusion in rats.
Chronic neuropathic pain is a significant consequence of spinal cord injury (SCI) that is associated with evoked pain, including allodynia and/or hyperalgesia. Allodynia is defined as a painful response to normally innocuous stimuli, and hyperalgesia occurs when there is an amplified pain response to normally noxious stimuli. We describe a model of a unilateral cervical level (C5) contusion injury where sensory recovery was assessed weekly for 6 weeks in 32 adult, female, Sprague-Dawley rats. ⋯ The contralesional forepaw and both hindpaws of rats showed a slight increase in paw withdrawal threshold to tactile stimuli acutely after SCI, corresponding to ipsilesional forelimb motor deficits that resolve over time. That there is no difference among allodynic and non-allodynic groups in overall spared tissue or specifically of the dorsal column or ventrolateral white matter where ascending sensory tracts reside suggests that SCI-induced pain does not depend solely on the size or extent of the lesion, but that other mechanisms are in play. These observations provide a valid model system for future testing of therapeutic interventions to prevent the onset or to reduce the debilitating effects of chronic neuropathic pain after SCI.
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Journal of neurotrauma · May 2013
Intravenous infusion of magnesium chloride improves epicenter blood flow during the acute stage of contusive spinal cord injury in rats.
Vasospasm, hemorrhage, and loss of microvessels at the site of contusive or compressive spinal cord injury lead to infarction and initiate secondary degeneration. Here, we used intravenous injection of endothelial-binding lectin followed by histology to show that the number of perfused microvessels at the injury site is decreased by 80-90% as early as 20 min following a moderate T9 contusion in adult female rats. Hemorrhage within the spinal cord also was maximal at 20 min, consistent with its vasoconstrictive actions in the central nervous system (CNS). ⋯ The magnesium treatment seemed safe as it did not increase hemorrhage, despite the improved parenchymal blood flow. However, the treatment did not reduce acute microvessel, motor neuron or oligodendrocyte loss, and when infused for 7 days did not affect functional recovery or spared epicenter white matter over a 4 week period. These data suggest that microvascular blood flow can be restored with a clinically relevant treatment following spinal cord injury.
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Journal of neurotrauma · May 2013
Exercise training after spinal cord injury selectively alters synaptic properties in neurons in adult mouse spinal cord.
Following spinal cord injury (SCI), anatomical changes such as axonal sprouting occur within weeks in the vicinity of the injury. Exercise training enhances axon sprouting; however, the exact mechanisms that mediate exercised-induced plasticity are unknown. We studied the effects of exercise training after SCI on the intrinsic and synaptic properties of spinal neurons in the immediate vicinity (<2 segments) of the SCI. ⋯ The properties of spontaneous excitatory synaptic currents (sEPSCs) did not differ in trained and untrained animals. In contrast, evoked excitatory synaptic currents recorded after dorsal column stimulation were markedly increased in trained animals (peak amplitude 78.9±17.5 vs. 42.2±6.8 pA; charge 1054±376 vs. 348±75 pA·ms). These data suggest that 3 weeks of treadmill exercise does not affect the intrinsic properties of spinal neurons after SCI; however, excitatory synaptic drive from dorsal column pathways, such as the corticospinal tract, is enhanced.
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Journal of neurotrauma · May 2013
Axonal and glial responses to a mid-thoracic spinal cord hemisection in the Macaca fascicularis monkey.
A comprehensive understanding of the pathology of spinal cord injury (SCI) in non-human primates may facilitate greatly the development of new strategies to promote recovery in humans with SCI. Relatively few studies, however, have been conducted to systemically examine pathological changes in the monkey, a non-human primate, after SCI. We report axonal, glial, and fibrotic responses in the spinal cord of monkey Macaca fascicularis after a thoracic (T) 8-9 lateral hemisection. ⋯ In contrast to rodents, substantial reactive astrocytic responses at the lesion border were not observed in the monkey. Conversely, a deposit of robust fibrotic scar was observed at the injury epicenter, which filled the space originally created by the hemisection. Thus, understanding the pathology of monkey SCI may provide clinically relevant information in designing repair strategies targeting specific problems associated with human SCIs.