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15 September 2012, Volume 7 Issue 26 Previous Issue    Next Issue

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P75 and phosphorylated c-Jun are differentially regulated in spinal motoneurons following axotomy in rats Qiuju Yuan, Huanxing Su, Wutian Wu, Zhi-Xiu Lin 2012, 7 (26):  2005-2011.  Abstract ( 188 )   PDF (272KB) ( 945 )   Save The neurotrophin receptor (p75) activates the c-Jun N-terminal kinase (JNK) pathway. Activation of JNK and its substrate c-Jun can cause apoptosis. Here we evaluate the role of p75 in spinal motoneurons by comparing immunoreactivity for p75 and phosphorylated c-Jun (p-c-Jun), the production of JNK activation in axotomized motoneurons in postnatal day (PN)1, PN7, PN14 and adult rats. Intensive p-c-Jun was induced in axotomized motoneurons in PN1 and PN7. In PN14, p-c-Jun expression was sharply reduced after the same injury. The decreased expression of p-c-Jun at this age coincided with a developmental switch of re-expression of p75 in axotomized cells. In adult animals, no p-c-Jun but intensive p75 was detected in axotomized motoneurons. These results indicate differential expression or turnover of phosphorylation of c-Jun and p75 in immature versus mature spinal motoneurons in response to axonal injury. The non-co-occurrence of p75 and p-c-Jun in injured motoneurons indicated that p75 may not activate JNK pathway, suggesting that the p75 may not be involved in cell death in axotomized motoneurons. References | Related Articles | Metrics

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Brain-derived neurotrophic factor expression in dorsal root ganglion neurons in response to reanastomosis of the distal stoma after nerve grafting Wei Yu, Jian Wang, Mingzhu Xu, Hanjiao Qin, Shusen Cui 2012, 7 (26):  2012-2017.  Abstract ( 216 )   PDF (146KB) ( 803 )   Save Studies have shown that retreatment of the distal stoma after nerve grafting can stimulate nerve regeneration. The present study attempted to verify the effects of reanastomosis of the distal stoma, after nerve grafting, on nerve regeneration by assessing brain-derived neurotrophic factor expres-sion in 2-month-old rats. Results showed that brain-derived neurotrophic factor expression in L2-4 dorsal root ganglia began to increase 3 days after autologous nerve grafting post sciatic nerve injury, peaked at 14 days, decreased at 28 days, and reached similar levels to the sham-surgery group at 56 days. Brain-derived neurotrophic factor expression in L2-4 dorsal root ganglia began to increase 3 days after reanastomosis of the distal stoma, 59 days after autologous nerve grafting post sciatic nerve injury, significantly increased at 63 days, peaked at 70 days, and gradually decreased the-reafter, but remained higher compared with the sham-surgery group up to 112 days. The results of this study indicate that reanastomosis of the distal stoma after orthotopic nerve grafting stimulated brain-derived neurotrophic factor expression in L2-4 dorsal root ganglia. References | Related Articles | Metrics

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Human umbilical cord blood-derived mesenchymal stem cells promote regeneration of crush-injured rat sciatic nerves Mi-Ae Sung, Hun Jong Jung, Jung-Woo Lee, Jin-Yong Lee, Kang-Mi Pang, Sang Bae Yoo, Mohammad S. Alrashdan, Soung-Min Kim, Jeong Won Jahng, Jong-Ho Lee 2012, 7 (26):  2018-2027.  Abstract ( 201 )   PDF (353KB) ( 1318 )   Save Several studies have demonstrated that human umbilical cord blood-derived mesenchymal stem cells can promote neural regeneration following brain injury. However, the therapeutic effects of human umbilical cord blood-derived mesenchymal stem cells in guiding peripheral nerve regeneration remain poorly understood. This study was designed to investigate the effects of human umbilical cord blood-derived mesenchymal stem cells on neural regeneration using a rat sciatic nerve crush injury model. Human umbilical cord blood-derived mesenchymal stem cells (1 × 106) or a PBS control were injected into the crush-injured segment of the sciatic nerve. Four weeks after cell injection, brain-derived neurotrophic factor and tyrosine kinase receptor B mRNA expression at the lesion site was increased in comparison to control. Furthermore, sciatic function index, Fluoro Gold-labeled neuron counts and axon density were also significantly increased when compared with control. Our results indicate that human umbilical cord blood-derived mesenchymal stem cells promote the functional recovery of crush-injured sciatic nerves. Related Articles | Metrics

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Reduced information transmission in the internal segment of the globus pallidus of 1-methyl-4- phenyl-1,2,3,6-tetrahydropyridine-induced rhesus monkey models of Parkinson’s disease Yan He, Jue Wang, Guodong Gao, Guangjun Zhang 2012, 7 (26):  2028-2035.  Abstract ( 199 )   PDF (354KB) ( 885 )   Save Rhesus monkey models of Parkinson’s disease were induced by injection of N-methyl-4-phenyl- 1,2,3,6-tetrahydropyridine. Neural firings were recorded using microelectrodes placed in the internal segment of the globus pallidus. The wavelets and power spectra show gradual power reduction during the disease process along with increased firing rates in the Parkinson’s disease state. Sin-gular values of coefficients decreased considerably during tremor-related activity as well as in the Parkinson’s disease state compared with normal signals, revealing that higher-frequency compo-nents weaken when Parkinson’s disease occurs. We speculate that the death of neurons could be reflected by irregular frequency spike trains, and that wavelet packet decomposition can effectively detect the degradation of neurons and the loss of information transmission in the neural circuitry. Related Articles | Metrics

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Effects of progesterone on glutamate transporter 2 and gamma-aminobutyric acid transporter 1 expression in the developing rat brain after recurrent seizures Lingjuan Liu, Dingan Mao, Liqun Liu, Yu Huang, Tao Bo 2012, 7 (26):  2036-2042.  Abstract ( 200 )   PDF (318KB) ( 815 )   Save Seizures were induced by flurothyl inhalation. Rats were intramuscularly treated with progesterone after each seizure. Results demonstrated that glutamate transporter 2 and γ-aminobutyric acid transporter 1 expression levels were significantly increased in the cerebral cortex and hippocampus of the developing rat brain following recurrent seizures. After progesterone treatment, glutamate transporter 2 protein expression was upregulated, but γ-aminobutyric acid transporter 1 levels de-creased. These results suggest that glutamate transporter 2 and γ-aminobutyric acid transporter 1 are involved in the pathological processes of epilepsy. Progesterone can help maintain a balance between excitatory and inhibitory systems by modulating the amino acid transporter system, and protect the developing brain after recurrent seizures. Related Articles | Metrics

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Structure of the brachial plexus root and adjacent regions displayed by ultrasound imaging Zhengyi Li, Xun Xia, Xiaoming Rong, Yamei Tang, Dachuan Xu 2012, 7 (26):  2044-2050.  Abstract ( 171 )   PDF (347KB) ( 1080 )   Save Brachial plexuses of 110 healthy volunteers were examined using high resolution color Doppler ul-trasound. Ultrasonic characteristics and anatomic variation in the intervertebral foramen, intersca-lene, supraclavicular and infraclavicular, as well as the axillary brachial plexus were investigated. Results confirmed that the normal brachial plexus on cross section exhibited round or elliptic hy-poechoic texture. Longitudinal section imaging showed many parallel linear hypo-moderate echoes, with hypo-echo. The transverse processes of the seventh cervical vertebra, the scalene space, the subclavian artery and the deep cervical artery are important markers in an examination. The display rates for the interscalene, and supraclavicular and axillary brachial plexuses were 100% each, while that for the infraclavicular brachial plexus was 97%. The region where the normal brachial plexus root traversed the intervertebral foramen exhibited a regular hypo-echo. The display rate for the C5-7 nerve roots was 100%, while those for C8 and T1 were 83% and 68%, respectively. A total of 20 of the 110 subjects underwent cervical CT scan. High-frequency ultrasound can clearly display the outline of the transverse processes of the vertebrae, which were consistent with CT results. These results indicate that high-frequency ultrasound provides a new method for observing the morphol-ogy of the brachial plexus. The C7 vertebra is a marker for identifying the position of brachial plexus nerve roots. Related Articles | Metrics

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Neuroprotection and its molecular mechanism following spinal cord injury Nai-Kui Liu, Xiao-Ming Xu 2012, 7 (26):  2051-2062.  Abstract ( 195 )   PDF (328KB) ( 1066 )   Save Acute spinal cord injury initiates a complex cascade of molecular events termed ‘secondary injury’, which leads to progressive degeneration ranging from early neuronal apoptosis at the lesion site to delayed degeneration of intact white matter tracts, and, ultimately, expansion of the initial injury. These secondary injury processes include, but are not limited to, inflammation, free radical-induced cell death, glutamate excitotoxicity, phospholipase A2 activation, and induction of extrinsic and intrinsic apoptotic pathways, which are important targets in developing neuroprotective strategies for treatment of spinal cord injury. Recently, a number of studies have shown promising results on neuroprotection and recovery of function in rodent models of spinal cord injury using treatments that target secondary injury processes including inflammation, phospholipase A2 activation, and manipulation of the PTEN-Akt/mTOR signaling pathway. The present review outlines our ongoing research on the molecular mechanisms of neuroprotection in experimental spinal cord injury and briefly summarizes our earlier findings on the therapeutic potential of pharmacological treatments in spinal cord injury. References | Related Articles | Metrics

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Action observation as a tool for neurorehabilitation to moderate motor deficits and aphasia following stroke Denis Ertelt, Ferdinand Binkofski 2012, 7 (26):  2063-2074.  Abstract ( 192 )   PDF (184KB) ( 1230 )   Save The mirror neuron system consists of a set of brain areas capable of matching action observation with action execution. One core feature of the mirror neuron system is the activation of motor areas by action observation alone. This unique capacity of the mirror neuron system to match action perception and action execution stimulated the idea that mirror neuron system plays a crucial role in the understanding of the content of observed actions and may participate in procedural learning. These features bear a high potential for neurorehabilitation of motor deficits and of aphasia following stroke. Since the first articles exploring this principle were published, a growing number of follow-up studies have been conducted in the last decade. Though, the combination of action observation with practice of the observed actions seems to constitute the most powerful approach. In the present review, we present the existing studies analyzing the effects of this neurorehabilitative approach in clinical settings especially in the rehabilitation of stroke associated motor deficits and give a perspective on the ongoing trials by our research group. The data obtained up to date showed significant positive effect of action observation on recovery of motor functions of the upper limbs even in the chronic state after stroke, indicating that our approach might become a new standardized add-on feature of modern neurorehabilitative treatment schemes. References | Related Articles | Metrics

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Neuronal Fc gamma receptor I as a novel mediator for IgG immune complex-induced peripheral sensitization Lintao Qu 2012, 7 (26):  2075-2079.  Abstract ( 285 )   PDF (117KB) ( 1110 )   Save Chronic pain often accompanies immune-related diseases with an elevated level of IgG immune complex (IgG-IC) in the serum and/or the affected tissues though the underlying mechanisms are largely unknown. Fc gamma receptors (FcγRs), known as the receptors for the Fc domain of immunoglobulin G (IgG), are typically expressed on immune cells. A general consensus is that the activation of FcγRs by IgG-IC in such immune cells induces the release of proinflammatory cytokines from the immune cells, which may contribute to the IgG-IC-mediated peripheral sensitization. In addition to the immune cells, recent studies have revealed that FcγRI, but not FcγRII and FcγRIII, is also expressed in a subpopulation of primary sensory neurons. Moreover, IgG-IC directly excites the primary sensory neurons through neuronal FcγRI. These findings indicate that neuronal FcγRI provides a novel direct linkage between immunoglobulin and primary sensory neurons, which may be a novel target for the treatment of pain in the immune-related disorders. In this review, we summarize the expression pattern, functions, and the associated cellular signaling of FcγRs in the primary sensory neurons. Related Articles | Metrics