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Table of Content

    25 December 2014, Volume 9 Issue 24 Previous Issue    Next Issue
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    A novel mode of retinal regeneration: the merit of a new Xenopus model
    Masasuke Araki
    2014, 9 (24):  2125-2127.  doi: 10.4103/1673-5374.147942
    Abstract ( 259 )   PDF (358KB) ( 605 )   Save
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    Activities of nicotinic acetylcholine receptors modulate neurotransmission and synaptic architecture
    Akira Oda,Hidekazu Tanaka
    2014, 9 (24):  2128-2131.  doi: 10.4103/1673-5374.147943
    Abstract ( 275 )   PDF (194KB) ( 1340 )   Save

    The cholinergic system is involved in a broad spectrum of brain function, and its failure has been implicated in Alzheimer’s disease. Acetylcholine transduces signals through muscarinic and nicotinic acetylcholine receptors, both of which influence synaptic plasticity and cognition. However, the mechanisms that relate the rapid gating of nicotinic acetylcholine receptors to persistent changes in brain function have remained elusive. Recent evidence indicates that nicotinic acetylcholine receptors activities affect synaptic morphology and density, which result in persistent rearrangements of neural connectivity. Further investigations of the relationships between nicotinic acetylcholine receptors and rearrangements of neural circuitry in the central nervous system may help understand the pathogenesis of Alzheimer’s disease.

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    A novel artificial nerve graft for repairing long-distance sciatic nerve defects: a self-assembling peptide nanofiber scaffold-containing poly(lactic-co-glycolic acid) conduit
    Xianghai Wang, Mengjie Pan, Jinkun Wen, Yinjuan Tang, Audra D. Hamilton, Yuanyuan Li, Changhui Qian, Zhongying Liu, Wutian Wu, Jiasong Guo
    2014, 9 (24):  2132-2141.  doi: 10.4103/1673-5374.147944
    Abstract ( 183 )   PDF (6984KB) ( 1314 )   Save

    In this study, we developed a novel artificial nerve graft termed self-assembling peptide nanofiber scaffold (SAPNS)-containing poly(lactic-co-glycolic acid) (PLGA) conduit (SPC) and used it to bridge a 10-mm-long sciatic nerve defect in the rat. Retrograde tracing, behavioral testing and histomorphometric analyses showed that compared with the empty PLGA conduit implantation group, the SPC implantation group had a larger number of growing and extending axons, a markedly increased diameter of regenerated axons and a greater thickness of the myelin sheath in the conduit. Furthermore, there was an increase in the size of the neuromuscular junction and myofiber diameter in the target muscle. These findings suggest that the novel artificial SPC nerve graft can promote axonal regeneration and remyelination in the transected peripheral nerve and can be used for repairing peripheral nerve injury.

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    The Achyranthes bidentata polypeptide k fraction enhances neuronal growth in vitro and promotes peripheral nerve regeneration after crush injury in vivo
    Qiong Cheng, Chunyi Jiang, Caiping Wang, Shu Yu, Qi Zhang, Xiaosong Gu, Fei Ding
    2014, 9 (24):  2142-2150.  doi: 10.4103/1673-5374.147948
    Abstract ( 283 )   PDF (3670KB) ( 788 )   Save

    We have previously shown that Achyranthes bidentata polypeptides (ABPP), isolated from Achyranthes bidentata Blume (a medicinal herb), exhibit neurotrophic and neuroprotective effects on the nervous system. To identify the major active component of ABPP, and thus optimize the use of ABPP, we used reverse-phase high performance liquid chromatography to separate ABPP. We obtained 12 fractions, among which the fraction of ABPPk demonstrated the strongest neuroactivity. Immunocytochemistry and western blot analysis showed that ABPPk promoted neurite growth in cultured dorsal root ganglion explant and dorsal root ganglion neurons, which might be associated with activation of Erk1/2. A combination of behavioral tests, electrophysiological assessment, and histomorphometric analysis indicated that ABPPk enhanced nerve regeneration and function restoration in a mouse model of crushed sciatic nerve. All the results suggest that ABPPk, as the key component of ABPP, can be used for peripheral nerve repair to yield better outcomes than ABPP.

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    The effects of claudin 14 during early Wallerian degeneration after sciatic nerve injury
    Leilei Gong, Yun Zhu, Xi Xu, Huaiqin Li, Weimin Guo, Qin Zhao, Dengbing Yao
    2014, 9 (24):  2151-2158.  doi: 10.4103/1673-5374.147946
    Abstract ( 213 )   PDF (1869KB) ( 906 )   Save

    Claudin 14 has been shown to promote nerve repair and regeneration in the early stages of Wallerian degeneration (0–4 days) in rats with sciatic nerve injury, but the mechanism underlying this process remains poorly understood. This study reported the effects of claudin 14 on nerve degeneration and regeneration during early Wallerian degeneration. Claudin 14 expression was up-regulated in sciatic nerve 4 days after Wallerian degeneration. The altered expression of claudin 14 in Schwann cells resulted in expression changes of cytokines in vitro. Expression of claudin 14 affected c-Jun, but not Akt and ERK1/2 pathways. Further studies revealed that enhanced expression of claudin 14 could promote Schwann cell proliferation and migration. Silencing of claudin 14 expression resulted in Schwann cell apoptosis and reduction in Schwann cell proliferation. Our data revealed the role of claudin 14 in early Wallerian degeneration, which may provide new insights into the molecular mechanisms of Wallerian degeneration.

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    Transplantation of human amniotic epithelial cells repairs brachial plexus injury: pathological and biomechanical analyses
    Qi Yang, Min Luo, Peng Li, Hai Jin
    2014, 9 (24):  2159-2163.  doi: 10.4103/1673-5374.147947
    Abstract ( 202 )   PDF (635KB) ( 728 )   Save

    A brachial plexus injury model was established in rabbits by stretching the C6 nerve root. Immediately after the stretching, a suspension of human amniotic epithelial cells was injected into the injured brachial plexus. The results of tensile mechanical testing of the brachial plexus showed that the tensile elastic limit strain, elastic limit stress, maximum stress, and maximum strain of the injured brachial plexuses were significantly increased at 24 weeks after the injection. The treatment clearly improved the pathological morphology of the injured brachial plexus nerve, as seen by hematoxylin eosin staining, and the functions of the rabbit forepaw were restored. These data indicate that the injection of human amniotic epithelial cells contributed to the repair of brachial plexus injury, and that this technique may transform into current clinical treatment strategies.

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    Long-term treatment with PP2 after spinal cord injury resulted in functional locomotor recovery and increased spared tissue
    Odrick R. Rosas, Aranza I. Torrado, Jose M. Santiago, Ana E. Rodriguez, Iris K. Salgado, Jorge D. Miranda
    2014, 9 (24):  2164-2173.  doi: 10.4103/1673-5374.147949
    Abstract ( 195 )   PDF (1050KB) ( 670 )   Save

    The spinal cord has the ability to regenerate but the microenvironment generated after trauma reduces that capacity. An increase in Src family kinase (SFK) activity has been implicated in neuropathological conditions associated with central nervous system trauma. Therefore, we hypothesized that a decrease in SFK activation by a long-term treatment with 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyramidine (PP2), a selective SFK inhibitor, after spinal cord contusion with the New York University (NYU) impactor device would generate a permissive environment that improves axonal sprouting and/or behavioral activity. Results demonstrated that long-term blockade of SFK activation with PP2 increases locomotor activity at 7, 14, 21 and 28 days post-injury in the Basso, Beattie, and Bresnahan open field test, round and square beam crossing tests. In addition, an increase in white matter spared tissue and serotonin fiber density was observed in animals treated with PP2. However, blockade of SFK activity did not change the astrocytic response or infiltration of cells from the immune system at 28 days post-injury. Moreover, a reduced SFK activity with PP2 diminished Ephexin (a guanine nucleotide exchange factor) phosphorylation in the acute phase (4 days post-injury) after trauma. Together, these findings suggest a potential role of SFK in the regulation of spared tissue and/or axonal outgrowth that may result in functional locomotor recovery during the pathophysiology generated after spinal cord injury. Our study also points out that ephexin1 phosphorylation (activation) by SFK action may be involved in the repulsive microenvironment generated after spinal cord injury.

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    Thermomineral water promotes axonal sprouting but does not reduce glial scar formation in a mouse model of spinal cord injury
    Dubravka Aleksić, Milan Aksić, Nevena Divac, Vidosava Radonjić, Branislav Filipović, Igor Jakovčevski
    2014, 9 (24):  2174-2181.  doi: 10.4103/1673-5374.147950
    Abstract ( 194 )   PDF (1999KB) ( 625 )   Save

    Thermomineral water from the Atomic Spa Gornja Trep?a has been used for a century in the treatment of neurologic disease. The thermomineral water contains microelements, including lithium and magnesium, which show neural regeneration-promoting effects after central nervous system injury. In this study, we investigated the effects of oral intake of thermomineral water from the Atomic Spa Gornja Trep?a on nerve regeneration in a 3-month-old mouse model of spinal cord injury. The mice receiving oral intake of thermomineral water showed better locomotor recovery than those without administration of thermomineral water at 8 and 12 weeks after lower thoracic spinal cord compression. At 12 weeks after injury, sprouting of catecholaminergic axons was better in mice that drank thermomineral water than in those without administration of thermomineral water, but there was no difference in glial reaction to injury between mice with and without administration of thermomineral water. These findings suggest that thermomineral water can promote the nerve regeneration but cannot reduce glial scar formation in a mouse model of spinal cord injury.

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    Hyperbaric oxygen therapy improves local microenvironment after spinal cord injury
    Yang Wang, Shuquan Zhang, Min Luo, Yajun Li
    2014, 9 (24):  2182-2188.  doi: 10.4103/1673-5374.147951
    Abstract ( 207 )   PDF (464KB) ( 985 )   Save

    Clinical studies have shown that hyperbaric oxygen therapy improves motor function in patients with spinal cord injury. In the present study, we explored the mechanisms associated with the recovery of neurological function after hyperbaric oxygen therapy in a rat model of spinal cord injury. We established an acute spinal cord injury model using a modification of the free-falling object method, and treated the animals with oxygen at 0.2 MPa for 45 minutes, 4 hours after injury. The treatment was administered four times per day, for 3 days. Compared with model rats that did not receive the treatment, rats exposed to hyperbaric oxygen had fewer apoptotic cells in spinal cord tissue, lower expression levels of aquaporin 4/9 mRNA and protein, and more NF-200 positive nerve fibers. Furthermore, they had smaller spinal cord cavities, rapid recovery of somatosensory and motor evoked potentials, and notably better recovery of hindlimb motor function than model rats. Our findings indicate that hyperbaric oxygen therapy reduces apoptosis, downregulates aquaporin 4/9 mRNA and protein expression in injured spinal cord tissue, improves the local microenvironment for nerve regeneration, and protects and repairs the spinal cord after injury.

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    Mild hypothermia combined with a scaffold of NgR-silenced neural stem cells/Schwann cells to treat spinal cord injury
    Dong Wang, Jinhua Liang, Jianjun Zhang, Shuhong Liu, Wenwen Sun
    2014, 9 (24):  2189-2196.  doi: 10.4103/1673-5374.147952
    Abstract ( 192 )   PDF (788KB) ( 717 )   Save

    Because the inhibition of Nogo proteins can promote neurite growth and nerve cell differentiation, a cell-scaffold complex seeded with Nogo receptor (NgR)-silenced neural stem cells and Schwann cells may be able to improve the microenvironment for spinal cord injury repair. Previous studies have found that mild hypothermia helps to attenuate secondary damage in the spinal cord and exerts a neuroprotective effect. Here, we constructed a cell-scaffold complex consisting of a poly(D,L-lactide-co-glycolic acid) (PLGA) scaffold seeded with NgR-silenced neural stem cells and Schwann cells, and determined the effects of mild hypothermia combined with the cell-scaffold complexes on the spinal cord hemi-transection injury in the T9 segment in rats. Compared with the PLGA group and the NgR-silencing cells + PLGA group, hindlimb motor function and nerve electrophysiological function were clearly improved, pathological changes in the injured spinal cord were attenuated, and the number of surviving cells and nerve fibers were increased in the group treated with the NgR-silenced cell scaffold + mild hypothermia at 34°C for 6 hours. Furthermore, fewer pathological changes to the injured spinal cord and more surviving cells and nerve fibers were found after mild hypothermia therapy than in injuries not treated with mild hypothermia. These experimental results indicate that mild hypothermia combined with NgR gene-silenced cells in a PLGA scaffold may be an effective therapy for treating spinal cord injury.

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    Transplantation of placenta-derived mesenchymal stem cell-induced neural stem cells to treat spinal cord injury
    Zhi Li, Wei Zhao, Wei Liu, Ye Zhou, Jingqiao Jia, Lifeng Yang
    2014, 9 (24):  2197-2204.  doi: 10.4103/1673-5374.147953
    Abstract ( 325 )   PDF (6210KB) ( 1122 )   Save

    Because of their strong proliferative capacity and multi-potency, placenta-derived mesenchymal stem cells have gained interest as a cell source in the field of nerve damage repair. In the present study, human placenta-derived mesenchymal stem cells were induced to differentiate into neural stem cells, which were then transplanted into the spinal cord after local spinal cord injury in rats. The motor functional recovery and pathological changes in the injured spinal cord were observed for 3 successive weeks. The results showed that human placenta-derived mesenchymal stem cells can differentiate into neuron-like cells and that induced neural stem cells contribute to the restoration of injured spinal cord without causing transplant rejection. Thus, these cells promote the recovery of motor and sensory functions in a rat model of spinal cord injury. Therefore, human placenta-derived mesenchymal stem cells may be useful as seed cells during the repair of spinal cord injury.

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    Melatonin lowers edema after spinal cord injury
    Cheng Li, Xiao Chen, Suchi Qiao, Xinwei Liu, Chang Liu, Degang Zhu, Jiacan Su, Zhiwei Wang
    2014, 9 (24):  2205-2210.  doi: 10.4103/1673-5374.147954
    Abstract ( 260 )   PDF (1756KB) ( 752 )   Save

    Melatonin has been shown to diminish edema in rats. Melatonin can be used to treat spinal cord injury. This study presumed that melatonin could relieve spinal cord edema and examined how it might act. Our experiments found that melatonin (100 mg/kg, i.p.) could reduce the water content of the spinal cord, and suppress the expression of aquaporin-4 and glial fibrillary acidic protein after spinal cord injury. This suggests that the mechanism by which melatonin alleviates the damage to the spinal cord by edema might be related to the expression of aquaporin-4 and glial fibrillary acidic protein.

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