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    15 October 2017, Volume 12 Issue 10 Previous Issue    Next Issue
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    Embracing oligodendrocyte diversity in the context of perinatal injury
    Carolyn Tallon, Mohamed H. Farah
    2017, 12 (10):  1565-1574.  doi: 10.4103/1673-5374.217319
    Abstract ( 154 )   PDF (1034KB) ( 350 )   Save
    While the peripheral nervous system has the capacity to regenerate following a nerve injury, it is often at a slow rate and results in unsatisfactory recovery, leaving patients with reduced function. Many regeneration associated genes have been identified over the years, which may shed some insight into how we can manipulate this intrinsic regenerative ability to enhance repair following peripheral nerve injuries. Our lab has identified the membrane bound protease beta-site amyloid precursor protein-cleaving enzyme 1 (BACE1), or beta secretase, as a potential negative regulator of peripheral nerve regeneration. When beta secretase activity levels are abolished via a null mutation in mice, peripheral regeneration is enhanced following a sciatic nerve crush injury. Conversely, when activity levels are greatly increased by overexpressing beta secretase in mice, nerve regeneration and functional recovery are impaired after a sciatic nerve crush injury. In addition to our work, many substrates of beta secretase have been found to be involved in regulating neurite outgrowth and some have even been identified as regeneration associated genes. In this review, we set out to discuss BACE1 and its substrates with respect to axonal regeneration and speculate on the possibility of utilizing BACE1 inhibitors to enhance regeneration following acute nerve injury and potential uses in peripheral neuropathies.
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    Embracing oligodendrocyte diversity in the context of perinatal injury
    Jessie Newville, Lauren L. Jantzie, Lee Anna Cunningham
    2017, 12 (10):  1575-1585.  doi: 10.4103/1673-5374.217320
    Abstract ( 179 )   PDF (1015KB) ( 302 )   Save

    Emerging evidence is fueling a new appreciation of oligodendrocyte diversity that is overturning the traditional view that oligodendrocytes are a homogenous cell population. Oligodendrocytes of distinct origins, maturational stages, and regional locations may differ in their functional capacity or susceptibility to injury. One of the most unique qualities of the oligodendrocyte is its ability to produce myelin. Myelin abnormalities have been ascribed to a remarkable array of perinatal brain injuries, with concomitant oligodendrocyte dysregulation. Within this review, we discuss new insights into the diversity of the oligodendrocyte lineage and highlight their relevance in paradigms of perinatal brain injury. Future therapeutic development will be informed by comprehensive knowledge of oligodendrocyte pathophysiology that considers the particular facets of heterogeneity that this lineage exhibits.

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    On the road towards the global analysis of human synapses
    G. Aleph Prieto, Carl W. Cotman
    2017, 12 (10):  1586-1589.  doi: 10.4103/1673-5374.217321
    Abstract ( 133 )   PDF (485KB) ( 328 )   Save

    Synapses are essential units for the flow of information in the brain. Over the last 70 years, synapses have been widely studied in multiple animal models including worms, fruit flies, and rodents. In comparison, the study of human synapses has evolved significantly slower, mainly because of technical limitations. However, three novel methods allowing the analysis of molecular, morphological, and functional properties of human synapses may expand our knowledge of the human brain. Here, we briefly describe these methods, and evaluate how the information provided by each unique approach may contribute to the functional and anatomical analysis of the synaptic component of human brain circuitries. In particular, using tissue from cryopreserved human brains, synaptic plasticity can be studied in isolated synaptosomes by fluorescence analysis of single-synapse long-term potentiation (FASS-LTP), and subpopulations of synapses can be thoroughly assessed in the ribbons of brain tissue by array tomography (AT). Currently, it is also possible to quantify synaptic density in the living human brain by positron emission tomography (PET), using a novel synaptic radio-ligand. Overall, data provided by FASS-LTP, AT, and PET may significantly contribute to the global understanding of synaptic structure and function in both healthy and diseased human brains, thus directly impacting translational research.

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    Non-invasive electrical brain stimulation: from acute to late-stage treatment of central nervous system damage
    Petra Henrich-Noack, Elena G. Sergeeva, Bernhard A. Sabel
    2017, 12 (10):  1590-1594.  doi: 10.4103/1673-5374.217322
    Abstract ( 152 )   PDF (346KB) ( 346 )   Save

    Non-invasive brain current stimulation (NIBS) is a promising and versatile tool for inducing neuroplasticity, protection and functional rehabilitation of damaged neuronal systems. It is technically simple, requires no surgery, and has significant beneficial effects. However, there are various technical approaches for NIBS which influence neuronal networks in significantly different ways. Transcranial direct current stimulation (tDCS), alternating current stimulation (ACS) and repetitive transcranial magnetic stimulation (rTMS) all have been applied to modulate brain activity in animal experiments under normal and pathological conditions. Also clinical trials have shown that tDCS, rTMS and ACS induce significant behavioural effects and can – depending on the parameters chosen - enhance or decrease brain excitability and influence performance and learning as well as rehabilitation and protective mechanisms. The diverse phaenomena and partially opposing effects of NIBS are not yet fully understood and mechanisms of action need to be explored further in order to select appropriate parameters for a given task, such as current type and strength, timing, distribution of current densities and electrode position. In this review, we will discuss the various parameters which need to be considered when designing an NIBS protocol and will put them into context with the envisaged applications in experimental neurobiology and medicine such as vision restoration, motor rehabilitation and cognitive enhancement.

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    Using 3D bioprinting to produce mini-brain
    Hao-Wei Han, Shan-hui Hsu
    2017, 12 (10):  1595-1596.  doi: 10.4103/1673-5374.217325
    Abstract ( 138 )   PDF (255KB) ( 321 )   Save
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    Matrix bound vesicles and miRNA cargoes are bioactive factors within extracellular matrix bioscaffolds
    Yolandi van der Merwe, Anne E. Faust, Michael B. Steketee
    2017, 12 (10):  1597-1599.  doi: 10.4103/1673-5374.217324
    Abstract ( 151 )   PDF (513KB) ( 253 )   Save
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    Collagen 1 signaling at the central nervous system injury site and astrogliosis
    Sin Hui Neo, Bor Luen Tang
    2017, 12 (10):  1600-1601.  doi: 10.4103/1673-5374.217323
    Abstract ( 115 )   PDF (131KB) ( 277 )   Save
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    Can we treat neurodegenerative diseases by preventing an age-related decline in microRNA expression?
    Ilya A. Vinnikov, Andrii Domanskyi
    2017, 12 (10):  1602-1604.  doi: 10.4103/1673-5374.217328
    Abstract ( 134 )   PDF (426KB) ( 330 )   Save
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    Soluble interleukin 23 receptor gene therapy with adeno-associated vectors for the treatment of multiple sclerosis
    Ángel Edo, Juan Francisco Espinosa-Parrilla
    2017, 12 (10):  1605-1606.  doi: 10.4103/1673-5374.217327
    Abstract ( 117 )   PDF (286KB) ( 250 )   Save
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    Neuregulin-1: a novel regulator of glial response in spinal cord injury
    Hardeep Kataria, Soheila Karimi-Abdolrezaee
    2017, 12 (10):  1616-1617.  doi: 10.4103/1673-5374.217331
    Abstract ( 120 )   PDF (245KB) ( 306 )   Save
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    Mechanisms of retinal neuroprotection of calcium dobesilate: therapeutic implications
    Olga Simó-Servat, Cristina Solà-Adell, Patricia Bogdanov, Cristina Hernández, Rafael Simó
    2017, 12 (10):  1620-1622.  doi: 10.4103/1673-5374.217333
    Abstract ( 159 )   PDF (181KB) ( 307 )   Save
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    Pharmacological induced target temperature management after cardiac arrest: the capsaicinoids
    J. Marc Simard, Xiaofeng Jia, Volodymyr Gerzanich
    2017, 12 (10):  1623-1624.  doi: 10.4103/1673-5374.217334
    Abstract ( 145 )   PDF (128KB) ( 264 )   Save
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    Baicalin protects neonatal rat brains against hypoxic-ischemic injury by upregulating glutamate transporter 1 via the phosphoinositide 3-kinase/protein kinase B signaling pathway
    Zhi-qing Zhou, Yong-liang Li, Zhen-bo Ao, Zhi-li Wen, Qi-wen Chen, Zheng-gang Huang, Bing Xiao, Xiao-hua Yan
    2017, 12 (10):  1625-1631.  doi: 10.4103/1673-5374.217335
    Abstract ( 200 )   PDF (1430KB) ( 370 )   Save

    Baicalin is a flavonoid compound extracted from Scutellaria baicalensis root. Recent evidence indicates that baicalin is neuroprotective in models of ischemic stroke. Here, we investigate the neuroprotective effect of baicalin in a neonatal rat model of hypoxic-ischemic encephalopathy.Seven-day-old pups underwent left common carotid artery ligation followed by hypoxia (8% oxygen at 37°C) for 2 hours, before being injected with baicalin (120 mg/kg intraperitoneally) and examined 24 hours later. Baicalin effectively reduced cerebral infarct volume and neuronal loss, inhibited apoptosis, and upregulated the expression of p-Akt and glutamate transporter 1. Intracerebroventricular injection of the phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) inhibitor LY294002 30 minutes before injury blocked the effect of baicalin on p-Akt and glutamate transporter 1, and weakened the associated neuroprotective effect. Our findings provide the first evidence, to our knowledge that baicalin can protect neonatal rat brains against hypoxic-ischemic injury by upregulating glutamate transporter 1 via the PI3K/Akt signaling pathway.

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     The role of glycogen synthase kinase 3 beta in brain injury induced by myocardial ischemia/reperfusion injury in a rat model of diabetes mellitus
    Bo Zhao, Wen-wei Gao, Ya-jing Liu, Meng Jiang, Lian Liu, Quan Yuan, Jia-bao Hou, Zhong-yuan Xia
    2017, 12 (10):  1632-1639.  doi: 10.4103/1673-5374.217337
    Abstract ( 126 )   PDF (1120KB) ( 354 )   Save

    Myocardial ischemia/reperfusion injury can lead to severe brain injury. Glycogen synthase kinase 3 beta is known to be involved in myocardial ischemia/reperfusion injury and diabetes mellitus. However, the precise role of glycogen synthase kinase 3 beta in myocardial ischemia/reperfusion injury-induced brain injury is unclear. In this study, we observed the effects of glycogen synthase kinase 3 beta on brain injury induced by myocardial ischemia/reperfusion injury in diabetic rats. Rat models of diabetes mellitus were generated via intraperitoneal injection of streptozotocin. Models of myocardial ischemia/reperfusion injury were generated by occluding the anterior descending branch of the left coronary artery. Post-conditioning comprised three cycles of ischemia/reperfusion. Immunohistochemical staining and western blot assays demonstrated that after 48 hours of reperfusion, the structure of the brain was seriously damaged in the experimental rats compared with normal controls. Expression of Bax, interleukin-6, interleukin-8, terminal deoxynucleotidyl transferase dUTP nick end labeling, and cleaved caspase-3 in the brain was significantly increased, while expression of Bcl-2, interleukin-10, and phospho-glycogen synthase kinase 3 beta was decreased. Diabetes mellitus can aggravate inflammatory reactions and apoptosis. Ischemic post-conditioning with glycogen synthase kinase 3 beta inhibitor lithium chloride can effectively reverse these changes. Our results showed that myocardial ischemic post-conditioning attenuated myocardial ischemia/reperfusion injury-induced brain injury by activating glycogen synthase kinase 3 beta. According to these results, glycogen synthase kinase 3 beta appears to be an important factor in brain injury induced by myocardial ischemia/reperfusion injury.

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    Age-related connectivity differences between attention deficit and hyperactivity disorder patients and typically developing subjects: a resting-state functional MRI study
    Jisu Hong, Bo-yong Park, Hwan-ho Cho, Hyunjin Park
    2017, 12 (10):  1640-1647.  doi: 10.4103/1673-5374.217339
    Abstract ( 135 )   PDF (1409KB) ( 348 )   Save

    Attention deficit and hyperactivity disorder (ADHD) is a disorder characterized by behavioral symptoms including hyperactivity/impulsivity among children, adolescents, and adults. These ADHD related symptoms are influenced by the complex interaction of brain networks which were under explored. We explored age-related brain network differences between ADHD patients and typically developing (TD) subjects using resting state fMRI (rs-fMRI) for three age groups of children, adolescents, and adults. We collected rs-fMRI data from 184 individuals (27 ADHD children and 31 TD children; 32 ADHD adolescents and 32 TD adolescents;and 31 ADHD adults and 31 TD adults). The Brainnetome Atlas was used to define nodes in the network analysis. We compared three age groups of ADHD and TD subjects to identify the distinct regions that could explain age-related brain network differences based on degree centrality, a well-known measure of nodal centrality. The left middle temporal gyrus showed significant interaction effects between disease status (i.e., ADHD or TD) and age (i.e., child, adolescent, or adult) (P < 0.001). Additional regions were identified at a relaxed threshold (P < 0.05). Many of the identified regions (the left inferior frontal gyrus, the left middle temporal gyrus, and the left insular gyrus) were related to cognitive function. The results of our study suggest that aberrant development in cognitive brain regions might be associated with age-related brain network changes in ADHD patients. These findings contribute to better understand how brain function influences the symptoms of ADHD.

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    Toxic effect of acrylamide on the development of hippo­campal neurons of weaning rats
    Sheng-min Lai, Zi-ting Gu, Meng-meng Zhao, Xi-xia Li, Yu-xin Ma, Li Luo, Jing Liu
    2017, 12 (10):  1648-1654.  doi: 10.4103/1673-5374.217345
    Abstract ( 144 )   PDF (1708KB) ( 359 )   Save

    Although numerous studies have examined the neurotoxicity of acrylamide in adult animals, the effects on neuronal development in the embryonic and lactational periods are largely unknown. Thus, we examined the toxicity of acrylamide on neuronal development in the hippocampus of fetal rats during pregnancy. Sprague-Dawley rats were mated with male rats at a 1:1 ratio. Rats were administered 0, 5, 10 or 20 mg/kg acrylamide intragastrically from embryonic days 6–21. The gait scores were examined in pregnant rats in each group to analyze maternal toxicity. Eight weaning rats from each group were also euthanized on postnatal day 21 for follow-up studies. Nissl staining was used to observe histological change in the hippocampus. Immunohistochemistry was conducted to observe the condition of neurites, including dendrites and axons. Western blot assay was used to measure the expression levels of the specific nerve axon membrane protein, growth associated protein 43, and the presynaptic vesicle membrane specific protein, synaptophysin. The gait scores of gravid rats significantly increased, suggesting that acrylamide induced maternal motor dysfunction. The number of neurons, as well as expression of growth associated protein 43 and synaptophysin, was reduced with increasing acrylamide dose in postnatal day 21 weaning rats. These data suggest that acrylamide exerts dose-dependent toxic effects on the growth and development of hippocampal neurons of weaning rats.

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    Effect of erythropoietin combined with hypothermia on serum tau protein levels and neurodevelopmental outcome in neonates with hypoxic-ischemic encephalopathy
    Hong-yan Lv1, 2, Su-jing Wu, Qiu-li Wang1 Li-hong Yang, Peng-shun Ren, Bao-jun Qiao, Zhi-ying Wang, Jia-hong Li, Xiu-ling Gu, Lian-xiang Li
    2017, 12 (10):  1655-1663.  doi: 10.4103/1673-5374.217338
    Abstract ( 152 )   PDF (409KB) ( 315 )   Save

    Although hypothermia therapy is effective to treat neonatal hypoxic-ischemic encephalopathy, many neonatal patients die or suffer from severe neurological dysfunction. Erythropoietin is considered one of the most promising neuroprotective agents. We hypothesized that erythropoietin combined with hypothermia will improve efficacy of neonatal hypoxic-ischemic encephalopathy treatment. In this study, 41 neonates with moderate/severe hypoxic-ischemic encephalopathy were randomly divided into a control group (hypothermia alone for 72 hours, n = 20) and erythropoietin group (hypothermia + erythropoietin 200 IU/kg for 10 days, n = 21). Our results show that compared with the control group, serum tau protein levels were lower and neonatal behavioral neurological assessment scores higher in the erythropoietin group at 8 and 12 days. However, neurodevelopmental outcome was similar between the two groups at 9 months of age. These findings suggest that erythropoietin combined with hypothermia reduces serum tau protein levels and improves neonatal behavioral neurology outcome but does not affect long-term neurodevelopmental outcome.

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    Locomotor analysis identifies early compensatory changes during disease progression and subgroup classification in a mouse model of amyotrophic lateral sclerosis
    Melissa M. Haulcomb, Rena M. Meadows, Whitney M. Miller, Kathryn P. McMillan, MeKenzie J. Hilsmeyer, Xuefu Wang, Wesley T. Beaulieu, Stephanie L. Dickinson, Todd J. Brown, Virginia M. Sanders, Kathryn J. Jones
    2017, 12 (10):  1664-1679.  doi: 10.4103/1673-5374.217346
    Abstract ( 173 )   PDF (2006KB) ( 339 )   Save

    Amyotrophic lateral sclerosis is a motoneuron degenerative disease that is challenging to diagnose and presents with considerable variability in survival. Early identification and enhanced understanding of symptomatic patterns could aid in diagnosis and provide an avenue for monitoring disease progression. Use of the mSOD1G93A mouse model provides control of the confounding environmental factors and genetic heterogeneity seen in amyotrophic lateral sclerosis patients, while investigating underlying disease-induced changes. In the present study, we performed a longitudinal behavioral assessment paradigm and identified an early hindlimb symptom, resembling the common gait abnormality foot drop, along with an accompanying forelimb compensatory mechanism in the mSOD1G93A mouse. Following these initial changes, mSOD1 mice displayed a temporary hindlimb compensatory mechanism resembling an exaggerated steppage gait. As the disease progressed, these compensatory mechanisms were not sufficient to sustain fundamental locomotor parameters and more severe deficits appeared. We next applied these initial findings to investigate the inherent variability in B6SJL mSOD1G93A survival. We identified four behavioral variables that, when combined in a cluster analysis, identified two subpopulations with different disease progression rates: a fast progression group and a slow progression group. This behavioral assessment paradigm, with its analytical approaches, provides a method for monitoring disease progression and detecting mSOD1 subgroups with different disease severities. This affords researchers an opportunity to search for genetic modifiers or other factors that likely enhance or slow disease progression. Such factors are possible therapeutic tar ets with the potential to slow disease progression and provide insight into the underlying pathology and disease mechanisms.

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    Protective effects of Bushen Tiansui decoction on hippocampal synapses in a rat model of Alzheimer’s disease
    Shan Hui, Yu Yang, Wei-jun Peng, Chen-xia Sheng, Wei Gong, Shuai Chen, Pan-pan Xu, Zhe Wang
    2017, 12 (10):  1680-1686.  doi: 10.4103/1673-5374.217347
    Abstract ( 162 )   PDF (893KB) ( 372 )   Save

    Bushen Tiansui decoction is composed of six traditional Chinese medicines: Herba Epimedii, Radix Polygoni multiflori, Plastrum testudinis,Fossilia Ossis Mastodi, Radix Polygalae, and Rhizoma Acorus tatarinowii. Because Bushen Tiansui decoction is effective against amyloid beta (Aβ) toxicity, we hypothesized that it would reduce hippocampal synaptic damage and improve cognitive function in Alzheimer’s disease. To test this hypothesis, we used a previously established animal model of Alzheimer’s disease, that is, microinjection of aggregated Aβ25–35 into the bilateral brain ventricles of Sprague-Dawley rats. We found that long-term (28 days) oral administration of Bushen Tiansui decoction (0.563, 1.688, and 3.375 g/mL; 4 mL/day) prevented synaptic loss in the hippocampus and increased the expression levels of synaptic proteins, including postsynaptic density protein 95, the N-methyl-D-aspartate receptor 2B subunit, and Shank1. These results suggested that Bushen Tiansui decoction can protect synapses by maintaining the expression of these synaptic proteins. Bushen Tiansui decoction also ameliorated measures reflecting spatial learning and memory deficits that were observed in the Morris water maze (i.e., increased the number of platform crossings and the amount of time spent in the target quadrant and decreased escape latency) following intraventricular injections of aggregated Aβ25–35 compared with those measures in untreated Aβ25–35-injected rats. Overall, these results provided evidence that further studies on the prevention and treatment of dementia with this traditional Chinese medicine are warranted.

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    Nischarin-siRNA delivered by polyethylenimine-alginate nanoparticles accelerates motor function recovery after spinal cord injury
    Yue-min Ding, Yu-ying Li, Chu Wang, Hao Huang, Chen-chen Zheng, Shao-han Huang, Yang Xuan, Xiao-yi Sun, Xiong Zhang
    2017, 12 (10):  1687-1694.  doi: 10.4103/1673-5374.217348
    Abstract ( 144 )   PDF (1271KB) ( 373 )   Save

    A previous study by our group found that inhibition of nischarin promotes neurite outgrowth and neuronal regeneration in Neuro-2a cells and primary cortical neurons. In recent years, more and more studies have shown that nanomaterials have good prospects in treatment of spinal cord injury. We proposed that small interfering RNA targeting nischarin (Nis-siRNA) delivered by polyethyleneimine-alginate (PEIALG) nanoparticles promoted motor function recovery in rats with spinal cord injury. Direct microinjection of 5 μL PEI-ALG/Nis-siRNA into the spinal cord lesion area of spinal cord injury rats was performed. From day 7 after surgery, Basso, Beattie and Bresnahan score was significantly higher in rats from the PEI-ALG/Nis-siRNA group compared with the spinal cord injury group and PEI-ALG/Control-siRNA group. On day 21 after injection, hematoxylin-eosin staining showed that the necrotic area was reduced in the PEI-ALG/Nis-siRNA group. Immunohistochemistry and western blot assay results confirmed successful inhibition of nischarin expression and increased protein expression of growth-associated protein-43 in the PEI-ALG/Nis-siRNA group. These findings suggest that a complex of PEI-ALG nanoparticles and Nis-siRNA effectively suppresses nischarin expression, induces expression of growth-associated protein-43, and accelerates motor function recovery after spinal cord injury.

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    Central projections and connections of lumbar primary afferent fibers in adult rats: effectively revealed using Texas red-dextran amine tracing
    Shi-de Lin, Tao Tang, Ting-bao Zhao, Shao-jun Liu
    2017, 12 (10):  1695-1702.  doi: 10.4103/1673-5374.217371
    Abstract ( 206 )   PDF (3270KB) ( 256 )   Save

    Signals from lumbar primary afferent fibers are important for modulating locomotion of the hind-limbs. However, silver impregnation techniques, autoradiography, wheat germ agglutinin-horseradish peroxidase and cholera toxin B subunit-horseradish peroxidase cannot image the central projections and connections of the dorsal root in detail. Thus, we injected 3-kDa Texas red-dextran amine into the proximal trunks of L4 dorsal roots in adult rats. Confocal microscopy results revealed that numerous labeled arborizations and varicosities extended to the dorsal horn from T12–S4, to Clarke’s column from T10–L2, and to the ventral horn from L1–5. The  abeled varicosities at the L4 cord level were very dense, particularly in laminae I–III, and the density decreased gradually in more rostral and caudal segments. In addition, they were predominately distributed in laminae I–IV, moderately in laminae V–VII and sparsely in laminae VIII–X. Furthermore, direct contacts of lumbar afferent fibers with propriospinal neurons were widespread in gray matter. In conclusion, the projection and connection patterns of L4 afferents were illustrated in detail by Texas red-dextran amine-dorsal root tracing.

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    End-to-side neurorrhaphy repairs peripheral nerve injury: sensory nerve induces motor nerve regeneration
    Qing Yu, She-hong Zhang, Tao Wang, Feng Peng, Dong Han, Yu-dong Gu
    2017, 12 (10):  1703-1707.  doi: 10.4103/1673-5374.217350
    Abstract ( 141 )   PDF (794KB) ( 364 )   Save

    End-to-side neurorrhaphy is an option in the treatment of the long segment defects of a nerve. It involves suturing the distal stump of the disconnected nerve (recipient nerve) to the side of the intimate adjacent nerve (donor nerve). However, the motor-sensory specificity after end-to-side neurorrhaphy remains unclear. This study sought to evaluate whether cutaneous sensory nerve regeneration induces motor nerves after end-to-side neurorrhaphy. Thirty rats were randomized into three groups: (1) end-to-side neurorrhaphy using the ulnar nerve (mixed sensory and motor) as the donor nerve and the cutaneous antebrachii medialis nerve as the recipient nerve; (2) the sham group: ulnar nerve and cutaneous antebrachii medialis nerve were just exposed; and (3) the transected nerve group: cutaneous antebrachii medialis nerve was transected and the stumps were turned over and tied. At 5 months, acetylcholinesterase staining results showed that 34% ± 16% of the myelinated axons were stained in the end-to-side group, and none of the myelinated axons were stained in either the sham or transected nerve groups. Retrograde fluorescent tracing of spinal motor neurons and dorsal root ganglion showed the proportion of motor neurons from the cutaneous antebrachii medialis nerve of the end-to-side group was 21% ± 5%. In contrast, no motor neurons from the cutaneous antebrachii medialis nerve of the sham group and transected nerve group were found in the spinal cord segment. These results confirmed that motor neuron regeneration occurred after cutaneous nerve end-to-side neurorrhaphy.

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    miR-30c promotes Schwann cell remyelination following peripheral nerve injury
    Sheng Yi, Qi-hui Wang, Li-li Zhao, Jing Qin, Ya-xian Wang, Bin Yu, Song-lin Zhou
    2017, 12 (10):  1708-1715.  doi: 10.4103/1673-5374.217351
    Abstract ( 225 )   PDF (1174KB) ( 336 )   Save

    Differential expression of miRNAs occurs in injured proximal nerve stumps and includes miRNAs that are firstly down-regulated and then gradually up-regulated following nerve injury. These miRNAs might be related to a Schwann cell phenotypic switch. miR-30c, as a member of this group, was further investigated in the current study. Sprague-Dawley rats underwent sciatic nerve transection and proximal nerve stumps were collected at 1, 4, 7, 14, 21, and 28 days post injury for analysis. Following sciatic nerve injury, miR-30c was down-regulated, reaching a minimum on day 4, and was then upregulated to normal levels. Schwann cells were isolated from neonatal rat sciatic nerve stumps, then transfected with miR-30c agomir and co-cultured in vitro with dorsal root ganglia. The enhanced expression of miR-30c robustly increased the amount of myelin-associated protein in the co-cultured dorsal root ganglia and Schwann cells. We then modeled sciatic nerve crush injury in vivo in Sprague-Dawley rats and tested the effect of perineural injection of miR-30c agomir on myelin sheath regeneration. Fourteen days after surgery, sciatic nerve stumps were harvested and subjected to immunohistochemistry, western blot analysis, and transmission electron microscopy. The direct injection of miR-30c stimulated the formation of myelin sheath, thus contributing to peripheral nerve regeneration. Overall, our findings indicate that miR-30c can promote Schwann cell myelination following peripheral nerve injury. The functional study of miR-30c will benefit the discovery of new therapeutic targets and the development of new treatment strategies for peripheral nerve regeneration.

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     In vitro neuroprotective effects of ciliary neurotrophic factor on dorsal root ganglion neurons with glutamate-induced neurotoxicity
    Shu-yun Wen, Ai-min Li, Kuan-qing Mi, Rui-zheng Wang, Hao Li, Hua-xiang Liu, Yi Xing
    2017, 12 (10):  1716-1723.  doi: 10.4103/1673-5374.217352
    Abstract ( 115 )   PDF (1214KB) ( 319 )   Save

    Ciliary neurotrophic factor has neuroprotective effects mediated through signal transducer and Janus kinase (JAK) 2/activator of transcription 3 (STAT3) and phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathways. Whether ciliary neurotrophic factor is neuroprotective for glutamate-induced excitotoxicity of dorsal root ganglion neurons is poorly understood. In the present study, the in vitro neuroprotective effects of ciliary neurotrophic factor against glutamate-induced excitotoxicity were determined in a primary culture of dorsal root ganglion neurons from Wistar rat embryos at embryonic day 15. Whether the JAK2/STAT3 and PI3K/Akt signaling pathways were related to the protective effects of ciliary neurotrophic factor was also determined. Glutamate exposure inhibited neurite outgrowth, cell viability, and
    growth-associated protein 43 expression and promoted apoptotic neuronal cell death, all of which were reversed by the administration of exogenous ciliary neurotrophic factor. Additionally, preincubation with either JAK2 inhibitor AG490 or PI3K inhibitor LY294002 blocked the neuroprotective effect of ciliary neurotrophic factor. These data indicate that the two pathways JAK2/STAT3 and PI3K/Akt play major roles in mediating the in vitro neuroprotective effects of ciliary neurotrophic factor on dorsal root ganglion neurons with glutamate-induced neurotoxicity.

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     Effect of glial cells on remyelination after spinal cord injury
    Hai-feng Wang, Xing-kai Liu, Rui Li, Ping Zhang, Ze Chu, Chun-li Wang, Hua-rui Liu, Jun Qi, Guo-yue Lv, Guang-yi Wang, Bin Liu, Yan Li, Yuan-yi Wang
    2017, 12 (10):  1724-1732.  doi: 10.4103/1673-5374.217354
    Abstract ( 249 )   PDF (312KB) ( 380 )   Save

    Remyelination plays a key role in functional recovery of axons after spinal cord injury. Glial cells are the most abundant cells in the central nervous system. When spinal cord injury occurs, many glial cells at the lesion site are immediately activated, and different cells differentially affect inflammatory reactions after injury. In this review, we aim to discuss the core role of oligodendrocyte precursor cells and crosstalk with the rest of glia and their subcategories in the remyelination process. Activated astrocytes influence proliferation, differentiation, and maturation of oligodendrocyte precursor cells, while activated microglia alter remyelination by regulating the inflammatory reaction after spinal cord injury. Understanding the interaction between oligodendrocyte precursor cells and the rest of glia is necessary when designing a therapeutic plan of remyelination after spinal cord injury.

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    Brain-derived neurotropic factor and GABAergic transmission in neurodegeneration and neuroregeneration
    Jinwook Kim, Sueun Lee, Sohi Kang, Sung-Ho Kim, Jong-Choon Kim, Miyoung Yang, Changjong Moon
    2017, 12 (10):  1733-1741.  doi: 10.4103/1673-5374.217353
    Abstract ( 144 )   PDF (345KB) ( 347 )   Save

    Neurotoxicity induced by stress, radiation, chemicals, or metabolic diseases, is commonly associated with excitotoxicity, oxidative stress, and neuroinflammation. The pathological process of neurotoxicity induces neuronal death, interrupts synaptic plasticity in the brain, and is similar to that of diverse neurodegenerative diseases. Animal models of neurotoxicity have revealed that clinical symptoms and brain lesions can recover over time via neuroregenerative processes. Specifically, brain-derived neurotropic factor (BDNF) and gamma-aminobutyric acid (GABA)-ergic transmission are related to both neurodegeneration and neuroregeneration. This review summarizes the accumulating evidences that suggest a pathogenic role of BDNF and GABAergic transmission, their underlying mechanisms, and the relationship between BDNF  and GABA in neurodegeneration and neuroregeneration. This review will provide a comprehensive overview of the underlying mechanisms of neuroregeneration that may help in developing potential strategies for pharmacotherapeutic approaches to treat neurotoxicity and neurodegenerative disease.

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    Diffusion tensor tractography studies on mechanisms of recovery of injured fornix
    Sung Ho Jang, Han Do Lee
    2017, 12 (10):  1742-1744.  doi: 10.4103/1673-5374.217355
    Abstract ( 124 )   PDF (306KB) ( 336 )   Save

    The fornix, which connects the medial temporal lobe and the medial diencephalon, is involved in episodic memory as an important part of the Papez circuit. The mechanisms of recovery of an injured fornix revealed by diffusion tensor tractography in the five studies are summarized as follows: 1) recovery through the nerve tract from an injured fornical crus to the medial temporal lobe via the normal pathway of the fornical crus; 2) recovery through the nerve tract originating from an ipsi-lesional fornical body connected to the ipsi-lesional medial temporal lobe via the splenium of the corpus callosum; 3) recovery through the nerve tract from the ipsi-lesional fornical body extending to the contra-lesional medial temporal lobe via the splenium of the corpus callosum; 4) recovery through the nerve tract originating from the ipsi-lesional fornical column connected to the ipsi-lesional medial temporal lobe; and 5) recovery through the nerve tract originating from the contra-lesional fornical column connected to the ipsi-lesional medial temporal lobe via the contra-lesional medial temporal lobe and the splenium of the corpus callosum. These diffusion tensor tractography studies on mechanisms of recovery of injured fornical crus appeared to provide useful information for clinicians caring for patients with brain injury, however, studies on this topic are still in the beginning stages.

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