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1.
Developmental changes of the fucosylated glycoconjugates in the dorsal root ganglia (DRG) of the rabbit were investigated histochemically using anti-fucosyl GM1 antibody and Ulex europaeus agglutinin 1 (UEA-1) lectin. Neither anti-fucosyl GM1 antibody nor UEA-1 lectin bound to the neural tubes or to the neural crest on embryonic day 14 (E14). Anti-fucosyl GM1 antibody binds diffusely to the DRG of E25. Large neurons unreactive with anti-fucosyl GM1 antibody appeared at 1 month and increased within 6 months after birth. Schwann cells immunoreactive with anti-fucosyl GM1 antibody came to be limited to the satellite cells surrounding the positive neurons. No staining with UEA-1 lectin was observed in the DRG of E25. Some small neurons became reactive with UEA-1 lectin within 1 month and remained to be so at 6 months after birth. Schwann cells including satellite cells were unreactive with this lectin. Since fucosyl GM1 was detected in the lipid fraction of DRGs from 1-month-old and 6-month-old rabbits, fucosyl GM1 itself should be the antigen molecule recognized by the anti-fucosyl GM1 antibody. Further study is necessary to elucidate the association between these developmental changes of the fucosylated glycoconjugates in DRG and their possible functional roles.  相似文献   

2.
Nerve injury, a significant cause of disability, may be treated more effectively using nerve guidance channels containing longitudinally aligned fibers. Aligned, electrospun nanofibers direct the neurite growth of immortalized neural stem cells, demonstrating potential for directing regenerating neurites. However, no study of neurite guidance on these fibers has yet been performed with primary neurons. Here, we examined neurites from dorsal root ganglia explants on electrospun poly-L-lactate nanofibers of high, intermediate, and random alignment. On aligned fibers, neurites grew radially outward from the ganglia and turned to follow the fibers upon contact. Neurite guidance was robust, with neurites never leaving the fibers to grow on the surrounding cover slip. To compare the alignment of neurites to that of the nanofiber substrates, Fourier methods were used to quantify the alignment. Neurite alignment, however striking, was inferior to fiber alignment on all but the randomly aligned fibers. Neurites on highly aligned substrates were 20 and 16% longer than neurites on random and intermediate fibers, respectively. Schwann cells on fibers assumed a very narrow morphology compared to those on the surrounding coverslip. The robust neurite guidance demonstrated here is a significant step toward the use of aligned, electrospun nanofibers for nerve regeneration. (c) 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007.  相似文献   

3.
Tissue engineering is founded on the concept of controlling the behavior of individual cells to stimulate tissue formation. This control is achieved by mimicking signals that manage natural tissue development or repair. These interdependent signals include cytokine delivery, extracellular matrix interactions, and cell-cell communication. Here, we report on the effect of spatial guidance as a signal for nerve tissue regeneration, using a simple in vitro model. We observe the acceleration of neurite extension from rat dorsal root ganglia within micron-scale tubes. Within these hydrogel-filled conduits, neurites were observed to extend more rapidly than when cultured within the hydrogel alone. The spatial cue also induced a change in tissue architecture, with the cabling of cells within the microconduit. The acceleration of neurite extension was found to be independent of conduit diameter within the range of 200 to 635 microm. Finally, our in vitro model enabled quantification of the effect of combining spatial control and localized nerve growth factor delivery.  相似文献   

4.
5.
Tsai SY  Chiu PY  Yang CP  Lee YH 《Neuroscience》2002,114(1):55-67
Corticosterone is the main adrenal glucocorticoids induced by stress in rats. Therapeutic use of high concentration of synthetic glucocorticoids in clinical treatment of spinal cord injury suggests that pharmacological action of glucocorticoids might be beneficial for nerve repair. In this article we cultured axotomized rat dorsal root ganglion neurons to investigate the effects of corticosterone and a glutamate receptor agonist kainic acid on neurite outgrowth. Our results revealed a synergistic effect of corticosterone and kainic acid in promoting neurite outgrowth when applied as early as one and two days in vitro, but not effective at three and four days in vitro. In addition, applied corticosterone and kainic acid were neurotoxic at three and four days in vitro but not at one and two days in vitro. The minimal concentrations of corticosterone and kainic acid to be effective were 10 microM and 1 mM, respectively. The neurotrophic effect of corticosterone and kainic acid was attenuated by the receptor tyrosine kinase A (TrkA) inhibitor AG-879. Western blot analysis and immunocytochemical studies revealed an increase of expressions of both TrkA and growth-associated protein GAP-43 in dorsal root ganglion neurons with combined treatment of corticosterone and kainic acid. Immunocytochemistry showed that corticosterone+kainic acid increase nerve growth factor immunoreactivity in dorsal root ganglion neurites and enhance GAP-43 immunointensity in dorsal root ganglion neurons. These results suggest that the neurotrophic effect of glucocorticoids on axonal regeneration might require facilitation of excitatory stimulation at an early stage of nerve injury, and nerve growth factor may mediate a growth signaling to accomplish the effect.  相似文献   

6.
The epithelial cells of the choroid plexus are a continuation of the ventricular ependymal cells and are regarded as modified ependymal cells. The present study was carried out to determine the influence of choroid plexus ependymal cells (CPECs) on axonal growth in vitro. Choroid plexuses were dissected from the fourth ventricle of postnatal day-1–10 mice, mechanically dissociated, and plated in fibronectin-coated culture dishes. CPECs had spread into monolayers with few endothelial cells in 3-week cultures. Some macrophages were scattered on the monolayer of CPECs. Dorsal root ganglia (DRG) were excised from mouse fetuses of 14-day gestation, dissociated with trypsin and cocultured on the CPEC monolayers. For comparison, dissociated DRG neurons were cocultured on astrocyte monolayers or cultured on laminin-coated plates. After 4.5 h culturing, the cultures were fixed and immunohistochemically double-stained for neurites and CPECs using antibodies against -tubulin III and S-100 , respectively. It was demonstrated that neurons extended many long neurites with elaborate branching on the surface of S-100-stained CPECs. In contrast, DRG neurons cultured on the astrocytes and on the laminin-coated plates had much shorter primary neurites with fewer branches than those cultured on the CPECs. The total length of neurites including primary neurites and their branches, of a single DRG neuron was 285 ± 14, 395 ± 15 and 565 ± 12 m on the laminin-coated plates, on astrocytes and on CPECs, respectively. Scanning electron microscopy revealed extension of neurites with well-developed growth cones on the ependymal cells. These results suggest that CPECs have a great capacity to promote neurite outgrowth from DRG neurons in vitro.  相似文献   

7.
目的 研究维生素C(Vitamin C,Vit.C)对大鼠背根神经节神经元轴突生长的影响,为探讨神经再生新策略提供基础。 方法 取新生SD大鼠背根神经节(dorsal root ganglion, DRG)进行神经元分离培养。在培养液中加入不同浓度的维生素C(0, 100, 200, 400 μmol/L)处理24 h后通过βIII tubulin, RhoA免疫组化以及鬼笔环肽染色对神经元突起的数量和长度、生长锥伪足数量、神经元胞体大小及其内RhoA表达强度进行分析。 结果 神经元突起的数量、长度,生长锥伪足的数量以及神经元胞体面积均随维生素C的浓度增高而增长,而神经元内RhoA表达强度则相应降低。 结论 维生素C可促进体外大鼠背根节神经元突起的生长,这可能与RhoA表达下调相关。  相似文献   

8.
Summary Sensory neurons and associated glial cells are known to express the cell-cell adhesion molecule E-cadherin. The cellular and subcellular localization of this molecule in the dorsal root ganglion, dorsal root, and spinal cord of postnatal mice was studied by the pre-embedding immunoelectron microscopic labelling technique. In the dorsal root and the superficial layer of the dorsal horn, a subset of fasciculating unmyelinated axons expressed E-cadherin at their axon-axon contacts at all ages studied, and these axons were clustered together and segregated from E-cadherin-negative axons. In contrast, pre-myelinating large-diameter axons in P2 mice as well as myelinated axons in mice from P14 to adulthood were E-cadherin-negative. Glial cells also expressed E-cadherin: In the dorsal root ganglia, all of the satellite cells expressed E-cadherin at contact sites with neurons, other satellite cells, and basal lamina, at all ages studied. In dorsal roots from P14 to adulthood, myelin-forming Schwann cells expressed E-cadherin at the outer mesaxons and the contact sites with basal lamina. Non-myelin-forming Schwann cells occasionally stained for this molecule at contact sites with the plasma membrane of E-cadherin-positive axons and at other sites. These results strongly suggest that E-cadherin plays an important role in the selective fasciculation of a particular subset of unmyelinated sensory fibres, and also in glial cell contacts.  相似文献   

9.
Current surgical treatment of spinal root injuries aims at reconnecting ventral roots to the spinal cord while severed dorsal roots are generally left untreated. Reactive changes in dorsal root ganglia (DRGs) and in injured dorsal roots after such complex lesions have not been analysed in detail. We studied dorsal root remnants and lesioned DRGs 6 months after C7 dorsal rhizotomy, ventral root avulsion and immediate ventral root replantation in adult rabbits. Replanted ventral roots were fixed to the spinal cord with fibrin glue only or with glue containing ciliary neurotrophic factor and/or brain-derived neurotrophic factor. Varying degrees of degeneration were observed in the deafferented dorsal spinal cord in all experimental groups. In cases with well-preserved morphology, small myelinated axons extended into central tissue protrusions at the dorsal root entry zone, suggesting sprouting of spinal neuron processes into the central dorsal root remnant. In lesioned DRGs, the density of neurons and myelinated axons was not significantly altered, but a slight decrease in the relative frequency of large neurons and an increase of small myelinated axons was noted (significant for axons). Unexpectedly, differences in the degree of these changes were found between control and neurotrophic factor-treated animals. Central axons of DRG neurons formed dorsal root stumps of considerable length which were attached to fibrous tissue surrounding the replanted ventral root. In cases where gaps were apparent in dorsal root sheaths, a subgroup of dorsal root axons entered this fibrous tissue. Continuity of sensory axons with the spinal cord was never observed. Some axons coursed ventrally in the direction of the spinal nerve. Although the animal model does not fully represent the situation in human plexus injuries, the present findings provide a basis for devising further experimental approaches in the treatment of combined motor/sensory root lesions.  相似文献   

10.
Dorsal root ganglion neurons from neonatal rats were grown in culture for 12 h and the extent of neurite outgrowth determined by counting the fraction of neurons with neurites. In the presence of high K+, veratridine or bradykinin the extent of neurite outgrowth was reduced by about 60%. The inhibitory effect of depolarisation was reversible and was abolished by nifedipine. gamma-Aminobutyric acid (GABA), baclofen and 2-chloroadenosine had no effect on neurite outgrowth in control cultures but abolished the inhibitory effect of depolarisation.  相似文献   

11.
Involvement of dorsal root ganglia in Fabry''s disease.   总被引:1,自引:0,他引:1       下载免费PDF全文
Bouts of shooting pain along the extremities are common in the early stages of Fabry's disease. No pathological explanation has been advanced to clarify the mechanism of such pain. In the present case neuronal storage of glycolipid was confined to dorsal root ganglia neurones only. It is suggested that this may explain the shooting pain in Fabry's disease. In hereditary sensory radicular neuropathy, familial dysautonomia, and tabes dorsalis, changes in dorsal root ganglia cells cause similar clinical signs and thus it may be concluded that shooting pains in Fabry's disease may be caused by damage to dorsal root ganglia neurones.  相似文献   

12.
Hou S  Tian W  Xu Q  Cui F  Zhang J  Lu Q  Zhao C 《Neuroscience》2006,137(2):519-529
Hyaluronic acid hydrogels modified with polyclonal anti-Nogo-66 receptor antibody were developed in order to promote regeneration in the injured CNS. These modified hydrogels were intended not only to deliver antibodies, but also to serve as a scaffold for neural regeneration following their implantation into injured tissue. Since unmodified hyaluronic acid-hydrogels do not support cell attachment, the gels were modified with polyclonal anti-Nogo-66 receptor with the aim of altering the surface properties of the gels in such a way as to improve neuronal adherence and survival. After evaluating the immobilization efficiency of the system, chicken dorsal root ganglia and dorsal root ganglia cells were planted on the surface of the modified gels to determine cell viability. Dorsal root ganglia were also cultured close to the gels in order to assay the inducement of neurite outgrowth. In dorsal root ganglia and cell viability assay, dorsal root ganglia and neuron cells could adhere to the modified hydrogels and survive well, but it did not happen to unmodified hydrogels. After 72 h, these attached cells were stained positively with immuno-staining for neurofilament. Neurite outgrowth inducement assay showed that the number and length of dorsal root ganglia neurites on the side toward modified hydrogels were significantly more than that on the opposite side (both P<0.01). The results reveal that hyaluronic acid-hydrogels modified with anti-Nogo-66 receptor can support neural cell attachment and survival in vitro. Furthermore, this system can greatly induce neurite outgrowth. The results also indicate that this modified hydrogels have potential to repair injury in the CNS.  相似文献   

13.
Degenerative change in cervical segments C5-C7 was documented to determine whether osteo-ligamentous adaptations were age-related. In addition, companion morphological studies were carried out to determine whether parallel changes occurred in related soft tissues, including DRG. Independent of the provoking stimulus, aberrant soft tissue change may be expected with segmental degeneration. Two associations were identified: between the incidence of segmental degeneration and severity of DRG distortion, and between segmental degeneration and DRG inflammatory mast cell density. Peripheral type C cells seemed more susceptible to compression in circumstances of DRG distortion. In light of neuropeptide expression in these cell types, predominant type C cell compression may be clinically relevant in the noxious cascade contributing to the sensation of pain.  相似文献   

14.
Secreted Slit proteins have previously been shown to signal through Roundabout (Robo) receptors to negatively regulate axon guidance and cell migration. During vertebrate development, Slit proteins have also been shown to stimulate branching and elongation of sensory axons and cortical dendrites. In this study, Slit1/Robo2 mRNA and protein expressions were detected in adult rat dorsal root ganglion (DRG) and in cultured DRG neurons. Treatment of both models with recombinant, soluble Slit1 protein was found to promote neurite outgrowth and elongation. In contrast, treatment with a recombinant human Robo2/Fc chimera inhibited neurite outgrowth and elongation. When adult DRG and cultured DRG neurons were pretreated with soluble recombinant human Robo2/Fc chimera, neurite outgrowth and elongation was not induced. These findings indicate that Slit1/Robo2 signaling may have a role in regulating peripheral nerve regeneration.  相似文献   

15.
16.
Dorsal root ganglia with nerve fibers, dissected from 3-month-old young adult mice and 26-month-old aged mice, were embedded in collagen gel. In the young adult mice regenerating neurites appeared from nerve-transected terminals after 12-24 h in culture, regardless of the length of fibers, but in the aged mice, regenerating neurites were first seen after 12-48 h. Administration of nerve growth factor to the explants markedly enhanced the growth of regenerating neurites from both the young adult and aged mice.  相似文献   

17.
Dorsal root ganglia, sodium channels, and fibromyalgia sympathetic pain   总被引:1,自引:0,他引:1  
Fibromyalgia (FM) is the most frequent cause of generalized pain in the community. Trauma and infection are frequent FM triggering events. A consistent line of investigation suggests that autonomic dysfunction may explain the multi-system features of FM, and that FM is a sympathetically maintained neuropathic pain syndrome. Dorsal root ganglia (DRG) are potential sympathetic-nociceptive short-circuit sites. Sodium channels located in DRG (particularly Nav1.7) act as molecular gatekeepers of pain detection at peripheral nociceptors. Different infecting agents may lie dormant in DGR. Trauma or infection can induce neuroplasticity with an over-expression of sympathetic fibers and sodium channels in DRG. Nerve growth factor (NGF) mediates these phenotypic changes, which enable catecholamines and/or sympathetic impulses to activate nociceptors. Several DRG sodium "channelopathies" have been recently associated to rare painful-dysautonomic syndromes, such as primary erythermalgia and paroxysmal extreme pain disorder (formerly familial rectal pain syndrome). We propose that enhanced DRG excitability may play a key role in FM pain. Individuals at risk would be those with genetically determined sympathetic hyperactivity, or those with inherent sodium channelopathies. Today's stressful environment may contribute to permanent sympathetic hyperactivity. Trauma or infection would induce sodium channels up-regulation and sympathetic sprouting in DRG through NGF over-expression. High levels of NGF have been reported in the cerebro-spinal fluid of FM patients. These post-traumatic (or post-infective) phenotypic changes would induce a sympathetically maintained neuropathic pain syndrome resulting in widespread pain, allodynia and paresthesias - precisely, the key clinical features of FM. If this hypothesis proves to be true, then sodium channel blockers could become therapeutic options for FM pain.  相似文献   

18.
目的: 研究神经生长颗粒(NGG)含药血清对体外培养新生大鼠背根神经节生长及高分子量神经丝蛋白(NF-H)和生长相关蛋白43(GAP43)表达的影响.方法: 采用体外大鼠背根神经节(DRG)植块培养,通过免疫荧光细胞化学法,观察不同剂量的含药血清对DRG神经突起生长的影响;采用DRG单细胞分离培养,通过实时荧光定量PCR和免疫印迹法分别观察不同剂量的含药血清对DRG细胞NF-H和GAP43基因及蛋白表达的影响.结果: 免疫荧光细胞化学法提示NGG含药血清能促进DRG神经突起的生长;实时荧光定量PCR和免疫印迹法结果提示NGG含药血清能增加体外培养的DRG细胞NF-H、 GAP43 mRNA和蛋白的表达.结论: NGG含药血清能促进体外培养DRG神经突起的生长并促进NF-H和GAP43的表达,表明NGG对发育期感觉神经元具有一定的神经营养作用.  相似文献   

19.
Sun WW  Liu J  Wang XY  Zhang LS  Zhang W  Li LY  Li H  Wang TH 《Neuroscience letters》2008,431(2):112-117
Changes in the platelet derived growth factor (PDGF) in the spared dorsal root ganglia (DRG) and associated spinal dorsal horns were evaluated in cats subjected to unilateral removal of L1-L5 and L7-S2 DRG, sparing the L6 DRG. The number of PDGF immunopositive neurons and protein expression decreased significantly in the spared DRG and associated dorsal horns of the L3 and L6 cord segments at 3 days post-operation (dpo). It bottomed to the lowest level at 7 dpo in the DRG, then returned to the control level at 14 dpo; while in the L6 dorsal horn, it rapidly increased at 7 dpo and exceeded the control level at 14 dpo. This showed a significant upregulation in the spared DRG and associated spinal dorsal horns, especially in the L6 cord segment following a transient decrease. Meanwhile, a significant upregulation of PDGF mRNA was also seen in L6 DRG and L3 and L6 dorsal horns at 3 dpo. The upregulation of the endogenous PDGF in the said structures indicated a potential role of this factor in spinal cord plasticity after partial dorsal root ganglia removal in cats.  相似文献   

20.
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