Journal of neurotrauma
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Journal of neurotrauma · Dec 2011
Simvastatin administration ameliorates neurobehavioral consequences of subarachnoid hemorrhage in the rat.
In the present study we assessed the neuroprotective effects of simvastatin in a rodent model of experimental subarachnoid hemorrhage (SAH). Based on recent data showing the role of statins not only in lowering the level of cholesterol but also in preventing cardiac and cerebrovascular damage in risk population, and in decreasing vasospasm and delayed ischemia after aneurysmal SAH, we investigated the neuroprotective effects of intraperitoneal administration of simvastatin (40 mg/kg/day for 5 consecutive days) in Sprague-Dawley rats 30 min after SAH, as compared to vehicle-treated SAH animals. ⋯ On days 1-4 post-SAH, simvastatin-treated rats have significantly improved beam balance scores (days 1-2, p<0.001; days 3-4, p<0.01), beam balance times (days 1-4, p<0.01), and latency to traverse the beam (days 1-3, p<0.01; day 2, p<0.005; day 4, p<0.0001) in comparison with control groups that, conversely, were not protected against SAH-related body weight changes. These results demonstrate that the administration of simvastatin may represent a beneficial therapeutic approach able to reduce post-SAH cognitive dysfunction.
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Journal of neurotrauma · Dec 2011
Schwann cell proliferation and macrophage infiltration are evident at day 14 after painful cervical nerve root compression in the rat.
Although it is known that different types of nerve root insults can produce radicular pain, it is not known whether the neuronal and Schwann cell pathologies in the nerve root vary between inflammation-induced nerve root injury and traumatic compression. This study examined the extent of Wallerian degeneration and associated cellular repair processes in the nerve root in the context of mechanical hyperalgesia resulting from different modes of painful nerve root injury. The C7 dorsal nerve root underwent a transient 10 gram-force compression (10 g), inflammation-induced irritation by chromic gut exposure (Cg), or a combination of those stimuli (10 g+Cg). ⋯ Unilateral exposure to chromic material induced bilateral increases in macrophages and Krox20-positive Schwann cells in the nerve roots, and substance P expression in the dorsal root ganglion (DRG) neurons. Results suggest that despite similar sensitivity, the extent of infiltrating macrophages and repopulated Schwann cells varies for pain from mechanical and/or chemical nerve root injury. Although these different cellular mechanisms may explain pain, they may also only reflect varying injury etiologies.
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Journal of neurotrauma · Nov 2011
ReviewToward a convergence of regenerative medicine, rehabilitation, and neuroprosthetics.
No effective therapeutic interventions exist for severe neural pathologies, despite significant advances in regenerative medicine, rehabilitation, and neuroprosthetics. Our current hypothesis is that a specific combination of tissue engineering, pharmacology, cell replacement, drug delivery, and electrical stimulation, together with plasticity-promoting and locomotor training (neurorehabilitation) is necessary to interact synergistically in order to activate and enable all damaged circuits. ⋯ Therefore, the objective of this review is to highlight the convergent themes, which we believe have a common goal of restoring function after neural damage. The convergent themes discussed in this review include modulation of inflammation and secondary damage, encouraging endogenous repair/regeneration (using scaffolds, cell transplantation, and drug delivery), application of electrical fields to modulate healing and/or activity, and finally modulation of plasticity.
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Journal of neurotrauma · Nov 2011
Single-walled carbon nanotubes chemically functionalized with polyethylene glycol promote tissue repair in a rat model of spinal cord injury.
Traumatic spinal cord injury (SCI) induces tissue damage and results in the formation of a cavity that inhibits axonal regrowth. Filling this cavity with a growth-permissive substrate would likely promote regeneration and repair. Single-walled carbon nanotubes functionalized with polyethylene glycol (SWNT-PEG) have been shown to increase the length of selected neurites in vitro. ⋯ We found that post-SCI administration of SWNT-PEG decreased lesion volume, increased neurofilament-positive fibers and corticospinal tract fibers in the lesion, and did not increase reactive gliosis. Additionally, post-SCI administration of SWNT-PEG induced a modest improvement in hindlimb locomotor recovery without inducing hyperalgesia. These data suggest that SWNT-PEG may be an effective material to promote axonal repair and regeneration after SCI.
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Many soldiers returning from the current conflicts in Iraq and Afghanistan have had at least one exposure to an explosive event and a significant number have symptoms consistent with traumatic brain injury. Although blast injury risk functions have been determined and validated for pulmonary injury, there is little information on the blast levels necessary to cause blast brain injury. Anesthetized male New Zealand White rabbits were exposed to varying levels of shock tube blast exposure focused on the head, while their thoraces were protected. ⋯ Scaling techniques were used to predict injury risk at other blast overpressure/duration combinations. The fatality risk function showed that the blast level needed to cause fatality from an overpressure wave exposure to the head was greater than the peak overpressure needed to cause fatality from pulmonary injury. This risk function can be used to guide future research for blast brain injury by providing a realistic fatality risk to guide the design of protection or to evaluate injury.