神经营养因子与周围神经再生

人们对神经营养因子在促进周围神经元的存活 ,维持周围神经元的数目方面的作用进行了大量研究。神经损伤后 ,给予外源性神经营养因子 ,能够产生与靶器官源性的神经营养因子相似的作用。周围神经再生过程中 ,神经营养因子NGF、NT 3和BDNF对背根节初级感觉神经元和脊髓运动神经元的存活及其表型的表达具有明确的选择性作用。其他神经营养因子 ,如CNTF、GDNF、LIF、GGF等 ,对神经元细胞也具有不同作用。本文将就神经营养因子对治疗周围神经损伤及周围神经疾病的潜在作用作一综述     

睫状神经营养因子在脊髓损伤中的研究进展

脊髓损伤(spinal cord injury,SCI)的修复是神经科学领域研究的热点问题."神经营养因子理论"认为,神经营养因子能促进神经元的存活、分化和修复.睫状神经营养因子(ciliary neurotrophic factor,CNTF)是目前研究比较多的营养因子之一.它不仅对体内外多种神经元包括感觉、运动、交感、副交感神经元及神经胶质细胞的存活具有促进作用,而且在促进轴突再生、防止受损神经元退变、维持运动神经元功能及诱导神经元和胶质细胞的分化方面也具有重要作用.近年来,关于CNTF在脊髓损伤修复中的作用也有较多的研究,现将对CNTF及其在脊髓损伤中的研究进展做一概述.     

神经营养因子(NGF、NT-3、BDNF及CNTF)和受体trkA、trkB、trkC在正常大鼠脊髓和胳鼠脊髓移植体的免疫组织化学研究

本研究采用免疫组织化学方法观察了NGF家族（NGF、NT－3、BDNF）和非NGF家族的CNTF以及NGF家族因子受体trkA、trkB、trkC在正常大鼠脊髓腰段的分布和胎鼠脊髓移植体在移植后4周的表达。在正常大鼠脊髓腰段,各神经营养因子及受体反应物主要存在于脊髓灰质,特别是前角的运动神经元。但在脊髓后角的分布稍有不同,BDNF阳性细胞的胞浆染色较深,胞核不染色;而NT－3的胞核染色较胞浆为深,核仁不染色。在胎鼠脊髓移植体,NGF、BDNF、CNTF和NT－3及受体trkA、trkB、trkC均有不同程度的染色。本实验结果揭示了在正常大鼠脊髓神经元内各神经营养因子及受体的表达,提示神经营养因子除具有靶源性来源以外,还有神经元自分泌的产物。而在胎鼠移植体内和其周围组织神经营养因子及其受体的表达,可能是在移植体内的移植细胞自分泌和成鼠脊髓损伤的刺激所引起的,这在移植体的存活和发育中有重要作用。     

胶质细胞源性神经营养因子对培养的背根神经节的影响

目的 探讨胶质细胞源性神经营养因子(GDNF)在体外促进正常胚胎大鼠背根神经节(DRGn)的存活及突起生长情况。方法 用原代分离培养法建立体外胚胎大鼠背根神经节单细胞培养体系，通过活体观察、MTT微量比色法、NSE免疫组织化学染色观察不同浓度GDNF对体外培养的正常感觉神经元的影响。结果 GDNF组培养的DRG神经元存活数量增加，神经元突起的长度比对照组明显增长。结论 GDNF能明显促进体外培养的正常大鼠胚胎背根神经节感觉神经元的存活及突起生长，表明GDNF对正常大鼠胚胎发育期感觉神经元具有神经营养作用。     

GDNF和HSV-GDNF对培养的大鼠脊髓运动神经元缺氧后的Bcl-2表达的影响

目的:观察细胞胶质源性神经营养因子(Glial cell line-derived neurotrophic factor,GDNF)和单纯疱疹病毒介导的GDNF(GDNF transformed by herpes simplex virus vector,HSV-GDNF)对体外培养的大鼠脊髓运动神经元缺氧-复氧时的作用和Bcl-2表达的影响。方法:观察缺氧2h、4h和缺氧4h后恢复供氧24、72h时,脊髓运动神经元存活数,并用抗Bcl-2抗血清行免疫组织化学染色,对Bcl-2免疫反应阳性神经元作平均光密度分析。结果:经GDNf、HSV-GDNF孵育的脊髓运动神经元缺氧-复氧后Bcl-2表达较对照组明显增强,神经元损伤程度减轻,神经元存活数明显高于对照组,且HSV-GDNF组的效果更好。结论:GDNF、HSV-GDNF对缺氧-复氧的大鼠脊髓运动神经元有保护作用,HSV-GDNF比GDNF更能增强缺氧-复氧后脊髓运动神经元Bcl-2的表达,提高神经元存活数,抑制缺氧后神经元的死亡。     

胶质细胞源性神经营养因子体外对脊髓运动神经元的作用

目的 :观察不同浓度的胶质细胞源性神经营养因子 (GDNF) ,对大鼠胚胎脊髓运动神经元生长活性的作用。方法 :取大鼠胚胎脊髓腹侧组织体外分离 ,进行原代细胞培养 ,应用抗神经微丝单克隆抗体 (mAb)SMI32进行运动神经元的免疫细胞化学染色 ,从细胞形态学及应用MTT比色法 ,研究GDNF对大鼠脊髓运动神经元的影响。结果 :GDNF能明显促进体外培养的大鼠脊髓运动神经元存活及突起的生长 (P <0 .0 5 ) ,且具有剂量依赖的趋势。结论 :不同浓度的GDNF对体外培养的大鼠胚胎脊髓运动神经元 ,有不同程度的促生长作用     

GDNFR-α在体外培养的大鼠脊髓和背根节神经元中分布的免疫组织化学研究

目的观察胶质细胞源性神经营养因子受体-α(GDNFR-α)在体外培养的大鼠脊髓和背根节神经元中的分布,探讨GDNF对脊髓运动神经元和感觉神经元的作用. 方法原代培养脊髓和背根节神经元,5d后行抗GDNFR-α多克隆抗体免疫组织化学SP法染色. 结果 GDNF免疫反应存在于体外培养的脊髓神经元、背根节神经元以及胶质细胞中. 结论 GDNF可能对脊髓神经元、背根节神经元和胶质细胞的生理功能具有一定的调节作用.     

GDNFR-〆在体外培养的大鼠脊髓和背根节神经元中分布的免疫组织化学研究

目的　观察胶质细胞源性神经营养因子受体 - α(GDNFR- α)在体外培养的大鼠脊髓和背根节神经元中的分布 ,探讨 GDNF对脊髓运动神经元和感觉神经元的作用。　方法　原代培养脊髓和背根节神经元 ,5 d后行抗 GDNFR- α多克隆抗体免疫组织化学 SP法染色。　结果　 GDNF免疫反应存在于体外培养的脊髓神经元、背根节神经元以及胶质细胞中。　结论　 GDNF可能对脊髓神经元、背根节神经元和胶质细胞的生理功能具有一定的调节作用     

GDNF促进大鼠背根神经元的存活和突起生长

探讨胶质细胞源性神经营养因子(GDNF)对正常胚胎大鼠背根神经节(DRGn)的存活及突起生长的作用。本实验采用神经组织原代分离培养的方法建立体外胚胎大鼠背根神经节单细胞培养体系，从细胞形态学及应用MTT。法观察1μg／L、10μg／L、50μg／L和100μg／L GDNF对体外培养的正常感觉神经元生长的影响。结果表明：GDNF能明显促进体外培养的正常大鼠背根神经节感觉神经元的存活及突起生长。提示GDNF对正常大鼠胚胎发育期感觉神经元具有神经营养作用。     

GDNF及HSV-GDNF对体外培养大鼠脊髓运动神经元受损后凋亡的影响

目的　观察胶质细胞源性神经营养因子 (GDNF)及单纯疱疹病毒载体介导的 GDNF(HSV- GDNF)对体外培养的胎鼠脊髓运动神经元在划痕损伤后凋亡的影响。　方法　对培养 12 d神经元行划痕损伤 ,并将其分成 4组 (无血清对照组、血清组、HSV- GDNF组和 GDNF组 ) ,给予不同培养液 ,定期观察各组的运动神经元存活数。分别于划痕损伤第 4d和第 7d时对神经元作 TU NEL 染色 ,检测运动神经元凋亡数 ,并在图像分析仪上对凋亡神经元作平均光密度的色谱分析。　结果　各组内运动神经元存活数与培养时间成反比。从对照组、HSV- GDNF组到 GDNF组 ,运动神经元凋亡数和凋亡神经元的平均光密度均依次减少 ,但对照组和血清组、GDNF组和 HSV-GDNF组间的运动神经元凋亡数以及凋亡神经元平均光密度均无显著差异。　结论　 GDNF和 HSV- GDNF能挽救生长发育过程中受损的脊髓运动神经元的凋亡 ,对体外培养的受损脊髓运动神经元具有一定的保护作用。     

Glial cell line-derived neurotrophic factor (GDNF) enhances sympathetic neurite growth in rat hearts at early developmental stages

Molecular signaling of sympathetic innervation of myocardium is an unresolved issue. The purpose of this study was to investigate the effect of neurotrophic factors on sympathetic neurite growth towards cardiomyocytes. Cardiomyocytes (CMs) and sympathetic neurons (SNs) were isolated from neonatal rat hearts and superior cervical ganglia, and were co-cultured, either in a random or localized way. Neurite growth from SNs toward CMs was assessed by immunohistochemistry for neurofilament M and α-actinin in response to neurotrophic factors-nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), ciliary neurotrophic factor (CNTF) and a chemical repellent, semaphorin 3A. As a result, GDNF as well as NGF and BDNF stimulated neurite growth. GDNF enhanced neurite outgrowth even under the NGF-depleted culture condition, excluding an indirect effect of GDNF via NGF. Quantification of mRNA and protein by real-time PCR and immunohistochemistry at different developmental stages revealed that GDNF is abundantly expressed in the hearts of embryos and neonates, but not in adult hearts. GDNF plays an important role in inducing cardiac sympathetic innervation at the early developmental stages. A possible role in (re)innervation of injured or transplanted or cultured and transplanted myocardium may deserve investigation.     

The IL-6/sIL-6R fusion protein hyper-IL-6 promotes neurite outgrowth and neuron survival in cultured enteric neurons.

The undisturbed development of the enteric nervous system depends on the supply of various neurotrophic factors during ontogenesis. Besides glial cell line-derived neurotrophic factor (GDNF), leukemia inhibitory factor (LIF) and ciliary neurotrophic factor (CNTF) take part in its development. CNTF and LIF belong to the interleukin-6 (IL-6) family of cytokines. The combination of IL-6 and the soluble IL-6 receptor accelerates peripheral nerve regeneration. In this study, we examined the effect of the fusion protein Hyper-IL-6, which consists of IL-6 and the soluble receptor sIL-6R, on neurite outgrowth and neuronal survival in vitro. Myenteric plexus of newborn rats was dissected and dissociated. Cells were grown in either serum-free chemically defined medium alone or medium supplemented with sIL-6R, IL-6, sIL-6+IL-6, Hyper-IL-6, CNTF, LIF, or GDNF. Average neurite outgrowth per neuron was highest in GDNF-treated and Hyper-IL-6-treated cultures. The number of neurite-bearing neurons was reduced in GDNF cultures compared with Hyper-IL-6-treated cells, so that the total neurite outgrowth was maximal after Hyper-IL-6 stimulation. Hyper-IL-6 furthermore stimulated neuronal survival and morphologic differentiation of the enteric glia.     

Ciliary neurotrophic factor (CNTF) plus soluble CNTF receptor α increases cyclooxygenase-2 expression, PGE2 release and interferon-γ-induced CD40 in murine microglia

Background  

Ciliary neurotrophic factor (CNTF) has been regarded as a potent trophic factor for motor neurons. However, recent studies have shown that CNTF exerts effects on glial cells as well as neurons. For instance, CNTF stimulates astrocytes to secrete FGF-2 and rat microglia to secrete glial cell line-derived neurotrophic factor (GDNF), which suggest that CNTF exerts effects on astrocytes and microglia to promote motor neuron survival indirectly. As CNTF is structurally related to IL-6, which can stimulate immune functions of microglia, we hypothesized that CNTF might exert similar effects.     

Integrin alphav and NCAM mediate the effects of GDNF on DA neuron survival,outgrowth, DA turnover and motor activity in rats

Glial cell line-derived neurotrophic factor (GDNF) is a specific neurotrophic factor for midbrain dopamine (DA) neurons, but the mechanism underlying the neurotrophic action of GDNF is not well known. The cell adhesion molecules integrin and Neural cell adhesion molecule (NCAM) play important roles in neurite outgrowth and fasciculation. In the present study, we found that subchronic GDNF administration to the pars compacta of substantia nigra in rats increased the expression of integrin alphav and NCAM. Immunostaining results demonstrated the wide distribution of integrin alphav and NCAM in all mesencephalic neurons. The results also demonstrated the co-expression of TH with integrin alphav and NCAM in the same neurons of mesencephalic culture. Further, GDNF significantly increased integrin alphav expression in single TH-positive neurons. Function-blocking anti-integrin alphav and anti-NCAM antibodies antagonized the effects of GDNF on DA neuron survival, outgrowth, DA turnover, and locomotor activity in rats. These results demonstrate that integrin alphav and NCAM mediate the effects of GDNF on DA neuron survival and outgrowth during development and on DA turnover and motor function during adulthood.     

Depletion of glial cell line-derived neurotrophic factor in substantia nigra neurons of Parkinson''s disease brain

The distribution of nerve growth factor (NGF), ciliary neurotrophic factor (CNTF), glial cell line-derived neurotrophic factor (GDNF), brain derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3) and neurotrophin-4 (NT-4) in substantia nigra pars compacta (SNc) of Parkinson's disease (PD) brains was investigated by immunofluorescence. Cases studied included four 69–77 year old neurologically normal male controls and four 72–79 year old male PD patients. Integrated optical densities (IODs) of immunofluorescence over individual neuromelanin-containing neurons and in areas of neuropil and the number of neurons on H & E stained adjacent sections were quantitated with the use of the BioQuant Image Analyzer. Data were statistically analyzed by ANOVA, including the unpaired two-tailed Student t-test and the Mann–Whitney test. The results showed 55.8% (P<0.0001) dropout of SNc neurons in PD brains compared to age-matched controls. Despite considerable neuronal dropout, immunofluorescent NTFs in the PD brains showed differential reductions that were consistent within the group as compared to age-matched controls: reductions were GDNF, 19.4%/neuron (P<0.0001), 20.2%/neuropil (P<0.0001); CNTF, 11.1%/neuron (P<0.0001), 9.4%/neuropil (P<0.0001); BDNF, 8.6%/neuron (P<0.0001), 2.5%/neuropil. NGF, NT-3 and NT-4 showed no significant differences within surviving neurons or neuropil. Since the depletion of GDNF both within surviving neurons and neuropil was twice as great as that of CNTF and BDNF and since the other NTFs showed no changes, GDNF, of the tested NTFs, is probably the most susceptible and the earliest to decrease in the surviving neurons of SNc. These observations suggest a role for decreased availability of GDNF in the process of SNc neurodegeneration in PD.     

NGF对新生大鼠隔神经元的神经营养作用

本实验观察了神经生长因子（ＮＧＦ，２．５ｓ）对无血清培养新生大鼠隔神经元生长发育的作用。结果证明，ＮＧＦ能促进新生大鼠隔神经元的存活，增加神经元胞体面积和直径，增加隔培养神经元中ＡＣｈＥ阳性神经元的数目。流式细胞分析显示，ＮＧＦ使神经元平均蛋白含量增加。以上结果表明：ＮＧＦ对新生大鼠隔神经元的生长发育具有促进作用。Ｐ＜０．０１３．ＮＧＦ增加隔培养神经元胞体面积、最长径和最短径图像分析结果可见：在前７ｄ，在神经元胞体面积、最长径和最短径等方面两组之间无明显差别，但在培养１４、２１和３０ｄ时，ＮＧＦ组培养神经元的平均胞体面积、最长径和最短径均大于对照组，经统计学处理有显著意义（表２）。表２对隔培养神经元胞体面积、最长径和最短径的影响（ｘ±ｓ）注：Ｎ＝３０与同时期对照组相比＊Ｐ＜０．０５Ｐ＜０．０１４．ＮＧＦ促进新生大鼠隔细胞的总量白合成用ＦＡＣＳ４４０流式细胞仪测定隔细胞的平均蛋白含量，结果表明：在培养３、７、１４和２１ｄ时，ＮＧＦ组培养细胞的平均蛋白含量均显著高于对照组（表３，Ｆｉｇ．１）。表３ＮＧＦ对隔神经元蛋白合成的影响（ｘ±ｓ）往：Ｎ＝５与同时期对照组相比　＊Ｐ＜０．０５５．ＮＧＦ提高隔神经元的ＡＣｈＥ?     

胶质细胞源性神经营养因子在成年大鼠三叉神经节及三叉神经核团中的分布

目的 观察胶质细胞源性神经营养因子(GDNF)在成年大鼠三叉神经节及三叉神经核团内的分布，探讨其对三叉神经感觉神经元及运动神经元的作用。方法 抗GDNF多克隆抗体免疫组织化学ABC法。结果 成年大鼠三叉神经运动核、三叉神经感觉核簇及三叉神经节中出现GDNF免疫反应阳性。结论 成年大鼠三叉神经运动核、三叉神经感觉核簇及三叉神经节中存在GDNF神经元。     

星形胶质细胞和神经生长因子对新生大鼠脑内P物质受体阳性神经元存活与突起生长的影响──体外培养研究

本实验用无血清培养进行神经元与星形胶质细胞的联合培养，观察了星形胶质细胞和神经生长因子对新生大鼠基底神经节和下位脑干内的P物质受体阳性神经元存活与生长的影响。结果表明：（1）含神经生长因子的NeurobasalMedium／N2supplement（N／N2）能支持新生鼠脑神经元的存活和神经元突起的生长，其效果与加血清的Dulbacco改良Eagle培养基（s－DMEM）相似；（2）利用星形胶质细胞作为滋养细胞，种植新生鼠基底神经节和下位脑干细胞于其上，可见星形胶质细胞对神经元的突起生长（生长锥）有明显的促进作用，其中基底神经节神经元神经突的生长优于下位脑干神经元；（3）免疫组织化学反应结果显示，来源于基底神经节的培养神经元有87％为P物质受体阳性神经元，而下位脑干为84％，P物质受体阳性神经元的胞体形态完整，突起生长良好。本实验表明含神经生长因子的N／N2Medium或s－DMEM可作为P物质受体神经元体外培养的培养基，星形胶质细胞可在一定程度上支持新生大鼠脑P物质受体神经元的存活与突起生长，并可保持其分化特性。