Journal of neurotrauma
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Journal of neurotrauma · Jun 2013
Beneficial function of cell division cycle 2 activity in astrocytes on axonal regeneration after spinal cord injury.
Migrating activity of reactive astrocytes induced after spinal cord injury (SCI) controls glial scar formation by limiting inflammatory responses around the injury area, and, therefore, can be beneficial for regenerative responses of spinal axons. Recently, we found that cell division cycle 2 (cdc2) activity in primary astrocytes facilitated neurite outgrowth of co-cultured neurons. Here, we investigated the effects of cdc2 activity on regenerative processes in vivo after SCI. ⋯ After SCI, regenerative responses of anterogradely labeled corticospinal tract (CST) axons were attenuated by purvalanol A treatment. Using the polymeric tube that was implanted into the spinal cord as a nerve guide conduit, we found that purvalanol A treatments reduced astrocyte migration into the tube graft and, in parallel, retarded the extension of spinal axons into the tube. These results suggest that astrocytes with cdc2 activity may play a permissive role in mediating regrowth of spinal axons after lesion.
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Journal of neurotrauma · Jun 2013
Acute delivery of EphA4-Fc improves functional recovery after contusive spinal cord injury in rats.
Blocking the action of inhibitory molecules at sites of central nervous system injury has been proposed as a strategy to promote axonal regeneration and functional recovery. We have previously shown that genetic deletion or competitive antagonism of EphA4 receptor activity promotes axonal regeneration and functional recovery in a mouse model of lateral hemisection spinal cord injury. ⋯ Consistent with functional improvement, using high-resolution ex vivo magnetic resonance imaging at 16.4T, we found that rats treated with EphA4-Fc had a significantly increased cross-sectional area of the dorsal funiculus caudal to the injury epicenter compared with controls. Our findings indicate that EphA4-Fc promotes functional recovery following contusive spinal cord injury and provides further support for the therapeutic benefit of treatment with the competitive antagonist in acute cases of spinal cord injury.
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Journal of neurotrauma · Jun 2013
Screening of biochemical and molecular mechanisms of secondary injury and repair in the brain after experimental blast-induced traumatic brain injury in rats.
Abstract Explosive blast-induced traumatic brain injury (TBI) is the signature insult in modern combat casualty care and has been linked to post-traumatic stress disorder, memory loss, and chronic traumatic encephalopathy. In this article we report on blast-induced mild TBI (mTBI) characterized by fiber-tract degeneration and axonal injury revealed by cupric silver staining in adult male rats after head-only exposure to 35 psi in a helium-driven shock tube with head restraint. We now explore pathways of secondary injury and repair using biochemical/molecular strategies. ⋯ ATP was not depleted, and adenosine correlated with 2'-cyclic AMP (cAMP), and not 5'-cAMP. Our data reveal (1) gene-array alterations similar to disorders of memory processing and a marked astrocyte response, (2) OS, (3) neuroinflammation with a sustained chemokine response, and (4) adenosine production despite lack of energy failure-possibly resulting from metabolism of 2'-3'-cAMP. A robust biochemical/molecular response occurs after blast-induced mTBI, with the body protected from blast and the head constrained to limit motion.
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Dementia pugilistica (DP), a suite of neuropathological and cognitive function declines after chronic traumatic brain injury (TBI), is present in approximately 20% of retired boxers. Epidemiological studies indicate TBI is a risk factor for neurodegenerative disorders including Alzheimer disease (AD) and Parkinson disease (PD). Some biochemical alterations observed in AD and PD may be recapitulated in DP and other TBI persons. ⋯ In addition, the levels of brain-derived neurotrophic factor and the axonal transport proteins kinesin and dynein were substantially decreased in DP relative to NDC participants. Traumatic brain injury is a risk factor for dementia development, and our findings are consistent with permanent structural and functional damage in the cerebral cortex and white matter of boxers. Understanding the precise threshold of damage needed for the induction of pathology in DP and TBI is vital.
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Journal of neurotrauma · Jun 2013
ReviewOmega-3 fatty acids as a putative treatment for traumatic brain injury.
Traumatic brain injury (TBI) is a global public health epidemic. In the US alone, more than 3 million people sustain a TBI annually. It is one of the most disabling injuries as it may cause motor and sensory deficits and lead to severe cognitive, emotional, and psychosocial impairment, crippling vital areas of higher functioning. ⋯ Although both animal models and human studies of brain injuries suggest they may provide benefits, there has been no clinical trial evaluating the effects of n-3 fatty acids on resilience to, or treatment, of TBI. This article reviews the known functions of n-3 fatty acids in the brain and their specific role in the cellular and biochemical pathways underlying neurotraumatic injury. We also highlight recent studies on the therapeutic impact of enhanced omega 3 intake in vivo, and how this may be a particularly promising approach to improving functional outcome in patients with TBI.