Bone mesenchymal stromal cells stimulate neurite outgrowth of spinal neurons by secreting neurotrophic factors

It has been demonstrated that bone mesenchymal stromal cells (BMSCs) stimulate neurite outgrowth from dorsal root ganglion (DRG) neurons. The present in vitro study tested the hypothesis that BMSCs stimulate the neurite outgrowth from spinal neurons by secreting neurotrophic factors. Spinal neurons were cocultured with BMSCs, fibroblasts and control medium in a non-contact system. Neurite outgrowth of spinal neurons cocultured with BMSCs was significantly greater than the neurite outgrowth observed in neurons cultured with control medium or with fibroblasts. In addition, BMSC-conditioned medium increased the length of neurites from spinal neurons compared to those of neurons cultured in the control medium or in the fibroblasts-conditioned medium. BMSCs expressed brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF). The concentrations of BDNF and GDNF in BMSC-conditioned medium were 132±12 and 70±6 pg ml(-1), respectively. The addition of anti-BDNF and anti-GDNF antibodies to BMSC-conditioned medium partially blocked the neurite-promoting effect of the BMSC-conditioned medium. In conclusion, our results demonstrate that BMSCs promote neurite outgrowth in spinal neurons by secreting soluble factors. The neurite-promoting effect of BMSCs is partially mediated by BDNF and GDNF.     

脑源性神经营养因子诱导的骨髓间质干细胞治疗脑缺血再灌注大鼠后的形态学改变

目的 观察脑源性神经营养因子(BDNF)诱导的骨髓间质干细胞(MSCs)移植治疗大鼠脑缺血冉灌注模型后的形态学改变。以探讨BDNF诱导的MSCs移植治疗脑缺血的可行性。方法以BDNF诱导或末诱导的MSCs移植治疗大鼠脑缺血再灌注模型2周及4周后。用患侧脑重量与对侧脑重量的比值来比较各组脑萎缩程度，电子显微镜下观察各组脑梗死灶边缘超微结构。结果移植诱导或未诱导MSCs的患侧脑／对侧脑重量比值均较未移植组高。但诱导组和未诱导组间比较无显著差异。移植BDNF诱导或未诱导MSCs可显著减少腑梗死灶边缘神经元坏死和凋亡，移植BDNF诱导MSCs还可减少血管内皮细胞凋亡。结论BDNF诱导或未诱导的MSCs移植治疗脑缺血再灌注可减轻脑萎缩程度，减少神经元和血管内皮细胞凋亡、坏死，具有潜在的临床应用价值。     

Bone marrow stromal cells promote neurite outgrowth of spinal motor neurons by means of neurotrophic factors in vitro

Transplantation of bone marrow stromal cells (BMSCs) into spinal cord injury models has shown significant neural function recovery; however, the underlying mechanisms have not been fully understood. In the present study we examined the effect of BMSCs on neurite outgrowth of spinal motor neuron using an in vitro co-culture system. The ventral horn of the spinal grey matter was harvested from neonatal Sprague–Dawley rats, cultured with BMSCs, and immunostained for neurofilament-200 (NF-200). Neurite outgrowth of spinal motor neurons was measured using Image J software. ELISA was used to quantify neurotrophic factors such as brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF) and nerve growth factor (NGF) in culture media, and antibodies or exogenous neurotrophic factors were used to block or mimic the effect of BMSCs on neurite outgrowth, respectively. The results showed that neurite outgrowth significantly increased in spinal motor neurons after co-cultured with BMSCs, while the secretion level of BDNF, GDNF and NGF was dramatically elevated in co-culture. However, the neurite outgrowth-promoting effect of BMSCs was found to significantly reduced using antibodies to BDNF, GDNF and NGF. In addition, a fraction of BMSCs was found to exhibit NF-200 immunoreactivity. These results indicated that BMSCs could promote neurite outgrowth of motor neurons by means of neurotrophic factors. The findings of the present study provided new cues for the treatment of spinal cord injury.     

Acidic and basic fibroblast growth factors enhance neurite outgrowth in cultured rat spinal cord neurons

Abstract

We have studied neurotrophic effects of acidic fibroblast growth factor (aFCF) and basic fibroblast growth factor (bFGF) on explanted ventral and dorsal spinal cord cultures from 13- and 14-day-old rat embryos. Cultures treated with aFCF and bFGF significantly enhanced neurite outgrowth with cultures of ventral spinal cord, but not with cultures of dorsal spinal cord. Our data suggest that aFCF and bFGF are potent neurotrophic factors on rat ventral spinal cord neurons in vitro. [Neurol Res 1995; 17: 70-72]     

多发性硬化、视神经脊髓炎患者血清及脑脊液中脑源性神经营养因子与胶质细胞源性神经营养因子水平

目的 探讨多发性硬化(MS)、视神经脊髓炎(NMO)患者血清及脑脊液中脑源性神经营养因子(BDNF)、胶质细胞源性神经营养因子(GDNF)水平及其神经保护作用.方法 对62例MS、NMO患者及21例对照者进行研究,患者组复发期进行扩展残疾状态量表(EDSS)评分、MRI检查及寡克隆带测定,液相芯片分析技术检测血清及脑脊液BDNF、GDNF浓度.结果 MS、NMO患者复发期血清及脑脊液BDNF(μg/L,MS患者:5.616±0.650、0.186±0.012;NMO患者6.584±0.929、0.176±0.006)、GDNF浓度(μg/L,MS患者:0.039、0.080;NMO患者0.029、0.050)与对照组(μg/L,血清:4.374±0.501、0.040;脑脊液:0.152±0.011、0.065)比较差异无统计学意义;脑脊液BDNF与GDNF浓度水平呈正相关(r=0.756,P=0.000),血清BDNF与GDNF浓度水平呈负相关(r=-0.329,P=0.018).血清及脑脊液BDNF、GDNF浓度与EDSS评分、血脑屏障指数、Delpech指数及Tourtellotte合成率无明显相关性.有或无脑萎缩的MS、NMO患者血清及腩脊液BDNF、GDNF浓度差异无统计学意义.结论 MS、NMO患者体内BDNF与GDNF水平相关,二者可能具有协同的神经保护作用.BDNF及GDNF与NMO、MS患者血脑屏障破坏及中枢神经系统内IgG合成无关,与神经功能残疾及脑萎缩的关系仍需研究.     

Temporal changes in the neurotrophic environment of the denervated striatum as determined by the survival and outgrowth of grafted fetal dopamine neurons

There is growing evidence that the neurotrophic environment of the denervated striatum may change with time following a lesion of the nigrostriatal pathway in young adult rats. To test this hypothesis, we implanted fetal dopamine grafts into the striatum at several different time points relative to the nigrostriatal pathway lesion and allowed the grafts to integrate with the host for a period of 1 month; subsequently, we observed the function and morphology of the dopamine grafts. Fetal grafts were implanted at the following time points relative to the lesion: 1 week before (-1 Week), at the same time (Week 0), 1 week after (1 Week), 4 weeks after (4 Weeks), or 12 weeks after (12 Weeks). Amphetamine-induced rotational behavior was assessed 4 weeks after grafting for all groups. Rotational scores indicate that grafts for the 1 Week group showed the greatest reversal of amphetamine-induced rotational behavior that was also significantly greater than the scores for the -1 Week group. Morphological analysis revealed that grafts in the Week 0, 1 Week and 4 Weeks groups showed a significantly larger area of tyrosine hydroxylase-positive (TH+) fiber outgrowth than in the -1 Week group, while fiber outgrowth for the 12 Weeks group was significantly lower than for the 1 Week group. Cell count analysis for TH+ neurons within the graft indicate a significantly greater number of TH+ neurons in grafts for the 1 Week group than in grafts for the -1 Week. The results of this study suggest that neurotoxic lesions may induce a compensatory increase in neurotrophic activity within the denervated striatum of young rats that is conducive to the survival and outgrowth of fetal dopamine grafts. These data also correlate well with reports that the expression of several specific dopaminergic neurotrophic factors within the striatum increase following a neurotoxic lesion of the nigrostriatal pathway in young adult rats.     

GDNF诱导分化骨髓基质细胞对PD大鼠的治疗作用

目的探讨胶质细胞源性神经营养因子（GDNF）诱导分化骨髓基质细胞（BMSCs）脑内移植对帕金森病（PD）模型的治疗作用。方法体外培养、分离和纯化的BMSCs，用5-溴脱氧尿核苷（BrdU）标记和GDNF诱导分化。分别将经GDNF诱导分化（A组）和未经GDNF诱导分化（B组）的BMSCs移植到PD大鼠模型纹状体区。另设生理盐水对照组（C组）和PD模型对照组（D组）。于不同时间点检测大鼠旋转行为变化，运用免疫荧光组织化学方法分析比较各组纹状体内酪氨酸羟化酶（TH）阳性细胞数量。结果①旋转行为检测显示，C组和D组在所有时间点未见明显变化；在移植后7～30d，A组和B组分别与C组和D组比较，旋转行为明显减少（P〈0．05）；A组比B组旋转行为减少更为显著（P〈0．05）。②免疫荧光组织化学检测显示，A组与B组比较，GFAP和TH阳性细胞数量明显增多（P〈0．05）。但各组自身各时程比较数量变化无统计学意义（P〉0．05）。结论A组的BMSCs脑内移植有效地改善了PD大鼠模型的旋转行为，提高了移植后TH阳性细胞的数量。     

人脐带间充质干细胞中神经营养因子的表达

目的 通过检测人脐带间充质干细胞(hUC-MSCs)的神经营养因子谱,以进一步认识hUC-MSCs通过分泌神经营养因子治疗神经损伤的作用. 方法 组织块培养法分离培养hUC-MSCs,流式细胞仪鉴定干细胞表面标记物,Raybio人细胞因子抗体芯片检测hUC-MSCs神经营养因子表达情况,RT-PCR检测hUC-MSCs神经营养因子的基因表达,ELISA法定量检测hUC-MSCs上清液中分泌的脑源性神经营养因子(BDNF)、胶质细胞源性神经营养因子(GDNF)、肝细胞生长因子(HGF)、神经营养因子3(NT-3)含量. 结果 流式细胞分析结果显示hUC-MSCs表面标记物CD29、CD44、CD90阳性(94.05％、90.75％、98.12％),CD34、CD45阴性(3.09％、0.80％).Raybio人细胞因子抗体芯片结果显示,与神经营养相关的因子BDNF、表皮生长因子(EGF)、GDNF、HGF、NT-3、血管内皮细胞生长因子(VEGF)、胰岛素样生长因子-1(IGF-1)、神经营养因子4(NT-4)在hUC-MSCs中均有表达.RT-PCR检验也证实IGF-1、VEGF、神经生长因子(NGF)、HGF、GDNF、NT-4、BDNF和NT-3基因在hUC-MSCs表达.ELISA检测细胞上清液中BDNF、GDNF、HGF、NT-3的含量分别为(475.20±32.22) pg/mL、(82.33±3.39) pg/mL、(704.50±12.86) pg/mL、(230.41±16.66) pg/mL,分别与空白对照组相比,差异均有统计学意义(P＜0.05). 结论 hUC-MSCs富含神经营养因子,是一种理想的用于神经损伤治疗的种子细胞.     

BDNF-expressing marrow stromal cells support extensive axonal growth at sites of spinal cord injury

Bone marrow stromal cells (MSCs) constitute a heterogeneous cell layer in the bone marrow, supporting the growth and differentiation of hematopoietic stem cells. Recently, it has been reported that MSCs harbor pluripotent stem cells capable of neural differentiation and that simple treatment of MSCs with chemical inducing agents leads to their rapid transdifferentiation into neural cells. We examined whether native or neurally induced MSCs would reconstitute an axonal growth-promoting milieu after cervical spinal cord injury (SCI), and whether such cells could act as vehicles of growth factor gene delivery to further augment axonal growth. One month after grafting to cystic sites of SCI, native MSCs supported modest growth of host sensory and motor axons. Cells "neurally" induced in vitro did not sustain a neural phenotype in vivo and supported host axonal growth to a degree equal to native MSCs. Transduction of MSCs to overexpress brain-derived neurotrophic factor (BDNF) resulted in a significant increase in the extent and diversity of host axonal growth, enhancing the growth of host serotonergic, coerulospinal, and dorsal column sensory axons. Measurement of neurotrophin production from implanted cells in the lesion site revealed that the grafts naturally contain nerve growth factor (NGF) and neurotrophin-3 (NT-3), and that transduction with BDNF markedly raises levels of BDNF production. Despite the extensive nature of host axonal penetration into the lesion site, functional recovery was not observed on a tape removal or rope-walking task. Thus, MSCs can support host axonal growth after spinal cord injury and are suitable cell types for ex vivo gene delivery. Combination therapy with other experimental approaches will likely be required to achieve axonal growth beyond the lesion site and functional recovery.     

稳定表达GDNF基因的骨髓基质干细胞对多巴胺能神经元的作用

目的 制备胶质细胞源性神经生长因子(GDNF)基因修饰的骨髓基质干细胞(MSCs)，观察其对多巴胺能神经元的作用，探索治疗帕金森氏病的新途径。方法 应用逆转录聚合酶链反应(RT-PCR)方法从新生小鼠大脑皮层细胞克隆出GDNF cDNA片断，以pEGFP-C1为载体导入MSCs，制备稳定表达GDNF基因的MSCs工程细胞，采用联合培养的技术通过倒置显微镜和免疫组织化学的方法观察MSCs和GDNF基因修饰的MSCs工程细胞与多巴胺能神经元之间的相互作用。结果 MSCs和GDNF基因修饰的MSCs工程细胞均能促进多巴胺能神经元的存活和生长，MSCs工程细胞作用更强。结论 成功构建了GDNF基因修饰的MSCs工程细胞，该细胞对多巴胺能神经元有明显营养保护作用，在帕金森病治疗中可能有重要价值。     

Effects of polychlorinated biphenyls (PCBs) on expression of neurotrophic factors in C6 glial cells in culture

Polychlorinated biphenyls (PCBs) are persistent environmental pollutants that affect nervous system function. Glial cells are among the first lines of defense in the nervous system and are involved in activities, including production of neurotrophic factors, which maintain an environment optimally suited for neuronal function. In this study, we investigated the effects of a commercial mixture of PCBs, Aroclor 1254 (A1254), on neurotrophic factor secretion by C6 cells in culture. C6 cells were exposed to medium containing 10 ppm A1254, 0.1% dimethyl sulfoxide (DMSO=vehicle), or normal culture medium. Glial cell line-derived neurotrophic factor (GDNF) and nerve growth factor (NGF) protein were measured by enzyme-linked immunosorbant assay. GDNF mRNA was measured by real-time RT-PCR. The role of protein kinase C (PKC) signaling in A1254 effects was investigated using bisindolylmaleimide, a PKC antagonist. Exposure to A1254 increased NGF (8.8x10(-5)+/-8.2x10(-6)pg NGF/cell) and GDNF (1.0x10(-4)+/-6.7x10(-6)pg GDNF/cell) secretion compared to DMSO treated controls (5.0x10(-5)+/-7.5x10(-6)pg NGF/cell and 6.2x10(-5)+/-3.1x10(-6)pg GDNF/cell). The effect of A1254 was long-lived, as GDNF secretion was elevated following 5 days of exposure (4.1x10(-5)+/-1.7x10(-6)pg GDNF/cell in A1254 exposed cells vs. 2.9x10(-5)+/-2.3x10(-6)pg GDNF/cell in DMSO exposed cells). GDNF mRNA expression was also elevated following exposure to A1254 (1.14+/-0.07 gene expression units in A1254 exposed cells vs. 0.8+/-0.07 gene expression units in DMSO exposed cells). Bisindolylmaleimide was able to block the effects of A1254 on GDNF secretion. Thus, one potential mechanism by which PCBs may alter nervous system function is via disruption of neurotrophic factor expression by glial cells. The observation that neurotrophic factor expression was increased following exposure to PCB may suggest that glial cells increase expression of neuroprotective genes following exposure to potentially damaging agents such as PCBs.     

骨髓间充质干细胞向多巴胺能神经元的诱导分化

背景：近年来研究发现,神经营养因子在骨髓间充质干细胞的分化中发挥重要作用。目前脑组织中具有再生能力的神经干细胞在体外是否具有直接诱导骨髓间充质干细胞分化为多巴胺能神经元的作用还未见报道。 目的：观察大鼠间充质干细胞在胶质细胞源性神经营养因子与神经干细胞共培养两种诱导条件下体外分化成多巴胺能神经元的能力。 方法：分离培养SD大鼠骨髓间充质干细胞,取第3代细胞分2组培养,一组细胞应用胶质细胞源性神经营养因子单独诱导,另一组细胞与已培养成球的神经干细胞共培养进行诱导,共培养之前行Brdu标记。诱导3 d后以免疫组织化学法检测各组贴壁细胞神经元特异性标志物神经原纤维和多巴胺能神经元特异性标志物酪氨酸羟化酶的表达,观察间充质干细胞的分化情况。 结果与结论：胶质细胞源性神经营养因子单独诱导组间充质干细胞在诱导24 h后胞体回缩呈锥形,突起延长且数量增多,有神经元样形态,且细胞间相互连接成网络状,3 d后部分细胞表达神经原纤维,其中少部分同时表达酪氨酸羟化酶。与神经干细胞共培养组神经干细胞球很快解离,迅速贴壁,共培养的贴壁细胞大量增殖且多呈神经元样,胞体细长多突起,相互间连接成网,多数贴壁细胞分别单独表达神经原纤维和酪氨酸羟化酶,少数细胞可见Brdu/神经原纤维,Brdu/胶质纤维酸性蛋白,Brdu/酪氨酸羟化酶双标阳性。提示间充质干细胞在胶质细胞源性神经营养因子、神经干细胞存在的情况下可定向转化为神经元,并有向多巴胺能神经元分化的可能。在该实验条件下胶质细胞源性神经营养因子效果好于神经干细胞。     

Somatostatin and calcitonin stimulate neurite regeneration of molluscan neurons in vitro

Isolated neurons from the gastropod Physella heterostropha fail to regenerate their neurites if cultured in defined medium in the absence of growth factors. A significant number of cultured neurons extend neurites if they are cultured in brain-conditioned or hemocyte-conditioned medium. Synthetic somatostatin and salmon calcitonin also stimulate neurite regeneration in a dose-dependent manner. Thyrotropin-releasing hormone, arginine vasotocin, and eledoisin fail to promote neurite outgrowth. It is concluded that, like other molluscan neurons, isolated neurons from Physella require the presence of factors that are released by brain tissue or are present in the hemolymph, and that somatostatin and calcitonin can, in part, substitute for the endogenous neurite-regenerating activities.     

Gene transfer of glial cell line-derived neurotrophic factor promotes functional recovery following spinal cord contusion

Neuronal cell death and the failure of axonal regeneration cause a permanent functional deficit following spinal cord injury (SCI). Administration of recombinant glial cell line-derived neurotrophic factor (GDNF) has previously been reported to rescue neurons following severe SCI, resulting in improved hindlimb locomotion in rats. In this study, thus, GDNF gene therapy using an adenoviral vector (rAd-GDNF) was examined in rats following SCI induced by dropping the NYU weight-drop impactor from a height of 25 mm onto spinal segment T9-T10. To evaluate the efficacy of intraspinal injection of recombinant adenovirus into the injured spinal cord, we observed green fluorescent protein (GFP) gene transfer in the contused spinal cord. GFP was effectively expressed in the injured spinal cord, and the most prominently transduced cells were astrocytes. The expression of GDNF was detected only in rats receiving rAd-GDNF, not the controls, and remained detectable around the injured site for at least 8 days. Open-field locomotion analysis revealed that rats receiving rAd-GDNF exhibited improved locomotor function and hindlimb weight support compared to the control groups. Immunohistochemical examination for the neuronal marker, calcitonin gene-related peptide (CGRP), showed an increase in CGRP+ neuronal fibers in the injured spinal cord in rats receiving rAd-GDNF treatment. Collectively, the results suggest that adenoviral gene transfer of GDNF can preserve neuronal fibers and promote hindlimb locomotor recovery from spinal cord contusion. This research should provide information for developing a clinical strategy for GDNF gene therapy.     

尼莫地平对大鼠面神经损伤的保护作用及GDNF表达的影响

目的 探讨尼莫地平对大鼠面神经损伤的保护作用及对胶质细胞源性神经生长因子(GDNF)表达的影响.方法 96只大鼠按随机数字表法分为假手术组、单纯损伤组、尼莫地平预处理组、尼莫地平后处理组,后三组建立大鼠面神经电损伤模型.应用HE染色、Western blotting等方法,观察大鼠面神经损伤后不同时期(1、3、6月)GDNF的动态表达变化及尼莫地平不同给药时间对其表达的影响.结果 与单纯损伤组相比,尼莫地平预处理组大鼠面神经损伤程度减轻,GDNF表达升高,持续时间延长;尼莫地平预处理组GDNF表达和尼莫地平后处理组间比较差异有统计学意义(P＜0.05);尼莫地平后处理组GDNF表达在3月、6月时与单纯损伤组比较差异无统计学意义(P＞0.05).结论 预防性应用尼莫地平可以保护面神经,其机制可能是通过调节GDNF的表达而实现的.

Abstract：

Objective To study the protective function of nimodipine on facial nerve injury and its effect on the expression of glial cell line-derived neurotrophic factor (GDNF). Methods Ninety-six SD rats were randomly divided into sham-operated group, facial nerve injury group, nimodipine pretreatment group, and nimodipine post-treatment group. Rat models of facial nerve injury in thc later 3groups were established. The dynamic changes of expression of GDNF were observed by HE staining and Western blotting in different treatment groups and at different time points (1, 3 and 6 months after the injury). Restdts Compared with the facial nerve injury group, the nimodipine pretreatment and post-treatment groups had significantly less severe nerve damage and significantly up-rcgulated expression of GDNF (P＜0.05). The expression of GDNF in the nimodipine pretreatment group was statistically higher than that in the nimodipine post-treatment group (P＜0.05). However, the expression of GDNF in the nimodipine post-treatment group was not statistically different from that in the facial nerve injury group 3 and 6 months after the injury (P＞0.05). Conclusion Nimodipine has significant facial nerve protective effect, and one of the mechanisms of nimodipine to protect the facial nerve is to regulate the GDNF expression.     

成年大鼠骨髓基质干细胞诱导分化为神经元样细胞不同方法比较的研究

目的 研究成年大鼠骨髓基质干细胞(BMSCs)诱导分化为神经元样细胞不同的方法，寻找它向神经细胞分化的最佳条件。方法 取纯度较高的BMSCs，通过不同的神经营养因子诱导法和抗氧化剂诱导法，进行抗巢蛋白(nestin)、神经元特异烯醇化酶(NSE)、神经胶质纤维酸性蛋白(GFAP)、酪氨酸羟化酶(TH)免疫细胞化学染色，观察相应的阳性细胞数。结果 诱导第3天A组(EGF：表皮生长因子，bFGF：碱性成纤维细胞生长因子，RA：全反式维甲酸)，B组(GDNF：胶质细胞系源性神经营养因子，BDNF：脑源性神经营养因子)，C组(EGF，bFGF，GDNF，BDNF和RA)的Nestin阳性细胞数较多，其中以C组最多，而D组(抗氧化剂)Nestin阳性细胞数少于前三组。A，B，C组的NSE，GFAP染色阳性细胞数较D组少，但D组有部分细胞发生死亡。诱导第7天A，B，C组的NSE，GFAP阳性细胞数较第3天时明显增多，C组最多，B组其次，Nestin阳性细胞数比例较第3天时明显减少。而D组的NSE，GFAP阳性细胞数少于其第3天时；C组诱导成神经细胞比例较高，阴性对照组和空白对照组极少或无阳性细胞。此外，神经营养因子诱导法生成神经样细胞的比例都多于胶质样细胞。结论 抗氧化剂诱导法分化诱导快，而神经营养因子诱导法分化诱导效率高，诱导后细胞生长状态明显好于前者，各种神经营养因子联合作用影响BMSCs的增殖和分化。     

Glial cell line derived neurotrophic factor promotes the recovery of dopamine neurons damaged by 6-hydroxydopamine in vitro

Glial cell line derived neurotrophic factor (GDNF) has been shown to be a potent neurotrophic factor for dopamine neurons in culture and to prevent the loss of substantia nigra dopamine neurons following in vivo lesions with 6-hydroxydopamine (6-OHDA). In this study we used mesencephalic cultures containing both neurons and glia to examine whether GDNF protects dopamine neurons from 6-OHDA toxicity in vitro. Our data show that GDNF does not prevent the loss of dopamine neurons caused by treatment with 6-OHDA in vitro. However, continuous exposure to GDNF increases the high affinity dopamine uptake in cultures treated with 6-OHDA, suggesting that it enhances the growth of damaged dopamine neurons. We also show that in vitro treatment with 6-OHDA causes widespread cell death in mesencephalic cultures, which is not restricted to dopamine neurons. The lack of selectivity of 6-OHDA toxicity when applied in vitro may explain the inability of GDNF to prevent the loss of dopamine neurons in mesencephalic cultures. The stimulation of the growth of 6-OHDA damaged dopamine neurons by GDNF, observed in our study, suggests that it may prove beneficial in the treatment of injured dopamine neurons.     

Immunosuppressive (FK506) and non-immunosuppressive (GPI1046) immunophilin ligands activate neurotrophic factors in the mouse brain

Based on the fact that several recent reports have indicated that non-immunosuppressive immunophilin ligands (IPLs) can activate neurite outgrowth or nerve regeneration, we investigated the neurotrophic factor-activating abilities of IPLs in vivo in order to clarify the molecular basis of neurotrophic-like activity. Both FK506 (an immunosuppressive IPL) and GPI1046 (a non-immunosuppressive IPL) significantly increased glial cell line-derived neurotrophic factor (GDNF) content in the substantia nigra. In addition, FK506 increased striatal brain-derived neurotrophic factor (BDNF) content significantly. Thus, our present results suggest that the molecular basis of IPL-induced neurotrophic-like activity may be dependent on GDNF and/or BDNF activation.     

慢病毒介导的胶质细胞系源性神经营养因子在骨髓基质细胞中的表达及其对乳胞素干预PC12细胞的保护作用

目的 建立慢病毒介导的胶质细胞系源性神经营养因子(glial cellline-derived neurotrophic factor,GDNF)表达系统,体外感染骨髓基质细胞,检测过表达GDNF对蛋白酶抑制剂引起的PC12细胞损伤的神经保护作用.方法 经双酶切和T4连接酶构建pLenti6/V5-GDNF表达质粒,经293FT细胞包装产生高滴度病毒.用RT-PCR、ELISA和免疫细胞化学方法检测感染骨髓基质细胞(bone marrow stromal cells,BMSCs)后GDNF的表达,并检测过表达GDNF对蛋白酶抑制剂乳胞素(1actacystin)引起的PC12细胞损伤的保护作用.结果 成功构建pLenti6/V5-GDNF表达质粒,获得高滴度具有感染能力的病毒储存液(5.6×105 TU/mL).BMSCs体外被感染后能大量分泌GDNF(接近800 pg/mL),过表达GDNF能减轻乳胞素(10 μmol/L)引起的PC12细胞损伤.结论 慢病毒介导的GDNF转染骨髓基质细胞后能分泌具有生物学活性的GDNF,对蛋白酶体抑制剂引起的PC12细胞损伤有保护作用.     

抗坏血酸联合胶质细胞源性神经营养因子诱导神经干细胞向多巴胺能神经元分化的研究

目的 研究抗坏血酸(AA)和胶质细胞源性神经营养因子(GDNF)对神经干细胞向多巴胺能神经元分化的影响.方法 从新生24h内的sD大鼠脑组织分离和培养神经干细胞,进行神经干细胞鉴定.第二代神经干细胞诱导培养基中分别给予AA或(和)GDNF,10d后终止诱导,进行DA能神经元特异性标记物酪氨酸羟化酶(TH)和多巴胺转运蛋白的免疫细胞化学检测和TH基因的RT-PCR检测.结果 各诱导组均检测到TH mRNA的表达;与对照组比较,AA及GDNF均能增加NSC向TH阳性细胞分化的比率(P<0.05);与单独运用100μmol/LAA或10ng/mlGDNF组比较,联合诱导组可明显提高NSCs向TH阳性细胞分化的比率(P<0.05).结论 AA和GDNF均能促进NSCs向DA能神经元分化,两者联合诱导后分化作用得到进一步加强.