Journal of neurotrauma
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Journal of neurotrauma · Dec 2013
Controlled cortical impact results in an extensive loss of dendritic spines that is not mediated by injury-induced amyloid-beta accumulation.
The clinical manifestations that occur after traumatic brain injury (TBI) include a wide range of cognitive, emotional, and behavioral deficits. The loss of excitatory synapses could potentially explain why such diverse symptoms occur after TBI, and a recent preclinical study has demonstrated a loss of dendritic spines, the postsynaptic site of the excitatory synapse, after fluid percussion injury. The objective of this study was to determine if controlled cortical impact (CCI) also resulted in dendritic spine retraction and to probe the underlying mechanisms of this spine loss. ⋯ To determine if Aβ contributes to spine loss after brain injury, we administered a γ-secretase inhibitor LY450139 after TBI. We found that while LY450139 administration could attenuate the TBI-induced increase in Aβ, it had no effect on dendritic spine loss after TBI. We conclude that the acute, global loss of dendritic spines after TBI is independent of γ-secretase activity or TBI-induced Aβ accumulation.
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Journal of neurotrauma · Dec 2013
The Effects of Repeat Traumatic Brain Injury on the Pituitary in Adolescent Rats.
Adolescents are one of the highest groups at risk for sustaining both traumatic brain injury (TBI) and repeat TBI (RTBI). Consequences of endocrine dysfunction following TBI have been routinely explored in adults, but studies in adolescents are limited, and show an incidence rate of endocrine dysfunction in 16-61% in patients, 1-5 years after injury. Similar to in adults, the most commonly affected axis is growth hormone (GH) and insulin-like growth hormone 1 (IGF-1). ⋯ Changes in weight and length of animals were measured as a potential consequence of GH and IGF-1 disruption. The results from the current study demonstrate that RTBI results in significant acute and chronic decreases in circulation of GH and IGF-1, reduction in weight gain and growth, and an increase in Evans Blue dye extravasation in the pituitary compared with sham and single injury animals. RTBI causes significant disruption of the GH/IGF-1 axis that may ultimately affect normal cognitive and physical development during adolescence.
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Journal of neurotrauma · Dec 2013
ETHOSUXIMIDE AND PHENYTOIN DOSE-DEPENDENTLY ATTENUTE ACUTE NONCONVULSIVE SEIZURES FOLLOWING TRAUMATIC BRAIN INJURY IN RATS.
Acute seizures frequently occur following severe traumatic brain injury (TBI) and have been associated with poor patient prognosis. Silent or nonconvulsive seizures (NCS) manifest in the absence of motor convulsion, can only be detected via continuous electroencephalographic (EEG) recordings, and are often unidentified and untreated. Identification of effective anti-epileptic drugs (AED) against post-traumatic NCS remains crucial to improve neurological outcome. ⋯ Compared with control treatment, the two highest PHT and ETX doses significantly reduced NCS incidence to 13-40%, reduced NCS frequency (1.8-6.2 episodes/rat), and delayed seizure onset: <20% of treated animals exhibited NCS within the first 48 h. NCS durations were also dose-dependently mitigated. For the first time, we demonstrate that ETX and PHT are effective against spontaneously occurring NCS following PBBI, and suggest that these AEDs may be effective at treating post-traumatic NCS.