小鼠神经干细胞的生物学特性观察

目的探讨小鼠神经干细胞体外原代培养的生长特性.方法用无血清与单细胞克隆技术对小鼠胚胎脑组织进行分离、培养,用光镜、免疫组织化学进行鉴定,并对其不同生长时期的生物学特性进行透射电镜观察.结果鼠胚胎分离细胞具有连续分化及克隆能力,克隆球和早期的原始细胞神经上皮干细胞蛋白(nestin)抗原呈阳性.成熟分化后胶质纤维酸性蛋白(GFAP)及神经丝-200(NF-200)抗原呈阳性.不同期电镜结果:培养2周的神经干细胞较原始,核大,细胞质少,细胞器不发达.将其继续培养到4周,部分细胞内可见到发达的细胞器,并在分化细胞中观察到神经微管、微丝、胶样丝和细胞间连接样结构.结论胚胎脑组织在体外培养并克隆成神经球,具有很强的增殖能力,是多分化潜能干细胞.     

胚胎大鼠脑纹状体和中脑神经干细胞的培养

目的研究大鼠脑不同部位胚胎神经干细胞的增殖分化特性。方法采用无血清培养基分离和培养大鼠脑的纹状体和中脑的神经干细胞,通过巢蛋白(nestin)表达和5-溴脱氧尿嘧啶(5-bromo-2'-deoxyuridine BrdU)染色,鉴定细胞的增殖能力;通过新生神经元、星形胶质细胞和少突胶质细胞的特异性免疫细胞化学染色,鉴定培养细胞的多潜能性。通过酪氨酸羟化酶的染色(tyrosine hydroxylase,TH)鉴定多巴胺神经元。结果二者在体外培养都可增殖成球,并能分化成神经系统3个谱系的细胞。纹状体增殖传代3个月,中脑培养细胞增殖维持3周。中脑干细胞分化TH阳性细胞比例高于纹状体。结论培养的胎鼠脑细胞是神经干细胞。纹状体干细胞增殖能力高于中脑干细胞,中脑干细胞更倾向于分化成TH阳性细胞。     

猫骨髓源性神经干细胞诱导分化的实验研究

目的探讨猫骨髓分离培养、诱导分化神经干细胞的可行性。方法无菌条件下行骨穿,梯度密度离心获取猫骨髓基质细胞,以“神经干细胞培养基”培养,用分化诱导因子进行体外培养和诱导分化。结果猫骨髓基质细胞在相应培养条件下能在体外培养中增殖、分化,克隆形成细胞球(或称“神经球”),这些细胞球能表达神经干细胞特异性抗原nestin,而且能进一步诱导分化出胶质样细胞和神经元样细胞,免疫细胞化学检测可见有胶质源性纤维酸性蛋白抗体(GFAP)和神经元特异性烯醇化酶(NSE)抗原表达。结论猫骨髓基质细胞在一定条件诱导下可分化成神经胶质样和神经元样细胞。     

胚胎大鼠神经干细胞的体外培养与鉴定

目的利用无血清培养和细胞克隆培养技术从孕鼠(14 d)胚胎中分离出神经干细胞,并进行传代培养和诱导分化。 方法 采用免疫细胞荧光化学染色方法观察不同代数细胞克隆球中nestin、neuN、GFAP阳性细胞比例,鉴定培养的原代和传代的细 胞类型结果随着传代次数增加,克隆球中nestin阳性细胞的比例无明显变化(P>0．05),不同代数的神经干细胞克隆球诱导分化 后均有一定比例的neuN与GFAP阳性细胞。结论 证实从胚胎大鼠大脑皮层分离培养的细胞是神经干细胞,提示体外培养体系中 培养的神经干细胞可以长期传代并保持于细胞的特性。     

脑源性神经营养因子对胎鼠神经干细胞向神经元方向分化的诱导

背景：神经元是中枢神经系统起主导功能的细胞，培养干细胞的最终目的是获得相应表型的神经元，从而促进中枢神经系统损伤的修复。但以往相关文献显示神经干细胞分化为神经元的比例不到30%。 目的：以脑源性神经营养因子作为诱导分化剂，观察其对胎鼠源性神经干细胞向神经元方向分化的作用。 设计、时间及地点：细胞学体外观察，于2006-06/2007-08在南京医科大学第一附属医院中心实验室完成。 材料：清洁级孕14~17 d的SD大鼠10只，诱导分化剂脑源性神经营养因子为Peprotech产品，胎牛血清为杭州四季青产品。 方法：孕鼠处死后取出胚胎，剪碎后机械法体外分离培养神经干细胞，锥虫蓝染色计数，调整细胞密度为2×106，添加B27及碱性成纤维细胞生长因子，置于37 ℃、体积分数为0.05的CO2恒温箱中原代培养，待细胞克隆球明显增大、中央变暗时传代扩增。将培养所得的干细胞克隆球分为2组，诱导组添加体积分数为0.01的胎牛血清+20 μg/L脑源性神经营养因子共培养，血清对照组仅添加体积分数为0.01的胎牛血清。 主要观察指标：在倒置显微镜下观察细胞生长、贴壁和分化情况。诱导分化5 d后，行神经元免疫组化鉴定，流式细胞仪检测神经元阳性细胞率。取原代培养未分化的神经干细胞及诱导分化3 d的两组细胞，RT-PCR检测内源性bHLH基因MASH-1的表达。 结果：原代培养可获得数十至数百个神经干细胞聚集在一起的神经克隆球，形态规则，立体感强；悬浮生长的克隆球经诱导分化后，逐渐失去其球状的立体外观，邻近克隆球发出的突起可相互连接，3 d后即有神经元、星形胶质细胞和少突胶质细胞从克隆周围出现。培养的神经干细胞呈巢蛋白阳性表达，诱导分化后呈微管相关蛋白2阳性表达。与血清对照组比较，诱导组神经元阳性细胞率显著升高（χ2=16.0，P < 0.05）。与未分化的神经干细胞比较，诱导组、血清对照组细胞MASH-1的表达均明显升高，且前者升高幅度明显强于后者（F=21.7，P < 0.05）。 结论：脑源性神经营养因子能促进神经干细胞向神经元方向分化，可能与内源性bHLH基因MASH-1的表达升高有关。     

小鼠胚胎干细胞体外向神经干细胞的分化研究

目的观察无血清培养法诱导小鼠胚胎干细胞(Embryome stem cell,ESCs)ESCs体外分化为神经干细胞(Neural stem cell,NSCs)的诱导效率.方法采用无血清培养法诱导小鼠ESCs体外分化为NSCs,对诱导不同时间点的细胞行免疫荧光,RT-PCR检测nestin的表达.结果诱导48 h开始出现nestinmRNA的表达,诱导72 h出现nestin蛋白表达.诱导120 h nestin的表达达高峰,阳性细胞率为(70.3±8.02)%.Nestin阳性细胞呈球形生长,可不断增殖.结论本诱导方法可获得较高纯度的NSCs,所获得的神经干细胞与脑内来源的NSCs有相似的生物学特性.     

成年小鼠嗅球神经干细胞的培养和鉴定

目的 建立完善的成年小鼠嗅球神经千细胞分离培养和鉴定方法,探索新的成年神经干细胞种子来源. 方法 用无血清方法 分离培养成年小鼠嗅球来源的神经干细胞;用克隆培养、5-溴2-脱氧尿嘧啶核昔(BrdU)整合的方法 检验培养细胞的干细胞特性;用免疫荧光细胞化学的方法 检测BrdU、神经干细胞标记物巢蛋白(nestin)和SOX2、分化的细胞标记物Tuj1、胶质纤维酸性蛋白(GFAP)、04的表达. 结果 从成年小鼠嗅球能够分离、培养出具有自我更新、增殖能力的神经球.构成神经球的细胞呈nestin和SOX2阳性,它们分化后产生TuJ1阳性的神经元、GFAP阳性的星形胶质细胞、04阳性的少突胶质细胞. 结论 成年小鼠嗅球存在神经干细胞,其能够在体外进行培养、增殖、分化.是神经干细胞的新的种子来源.     

人脑胶质瘤干细胞的分离、增殖和分化的研究

目的从人胶质瘤中分离并鉴定肿瘤干细胞。方法用神经干细胞无血清培养方法从胶质瘤中分离出具有单细胞克隆能力的细胞球,通过核型分析证明其肿瘤特性,用MTT法检测单克隆细胞增殖能力,应用免疫组织化学的方法检测克隆细胞nestin抗原和分化后相关神经细胞特异性抗原的表达。结果所获得的细胞球具有连续克隆的能力,nestin抗原阳性,并具有肿瘤核型,分化后的细胞表达星形胶质细胞和神经元特异性抗原。结论成功培养出脑胶质瘤肿瘤干细胞,该细胞具有自我更新、多向分化和很强的增殖能力等干细胞的特征。     

人脑胶质瘤肿瘤干细胞的培养及鉴定

目的:从人胶质瘤中分离并鉴定肿瘤干细胞。方法:用神经干细胞无血清培养方法从胶质瘤中分离出具有单细胞克隆能力的细胞球,通过核型分析证明其肿瘤特性,用MTT法检测单克隆细胞增殖能力,应用免疫组织化学的方法检测克隆细胞nestin抗原和分化后相关神经细胞特异性抗原的表达。结果:所获得的细胞球具有连续克隆的能力,nestin抗原阳性,并具有肿瘤核型,分化后的细胞表达星形胶质细胞和神经元特异性抗原。结论:成功培养出脑胶质瘤肿瘤干细胞,该细胞具有自我更新、多向分化和很强的增殖能力等干细胞的特征。     

表皮生长因子对脑源性神经生长因子诱导体外培养大鼠脑海马神经干细胞向神经元分化的影响*★

目的：获得大量神经干细胞并且能够控制其向神经元定向分化可为进一步修复损伤大脑和治疗退行性神经系统疾病奠定种子细胞基础，实验观察了表皮生长因子对脑源性神经生长因子诱导神经干细胞向神经元分化过程中的影响。 方法：实验于2007-08在中国医科大学神经解剖研究室完成。①材料：清洁级雄性成年SD大鼠3只，由中国医科大学实验动物部提供，实验过程中对动物的处置符合动物伦理学标准。②实验方法：无菌条件下分离大鼠脑海马组织，胰蛋白酶消化后采用无血清培养技术体外培养神经干细胞，传至第4代克隆球直径约为200 μm时，滴加DMEM/F12 + 2% B27 + 20 μg/L表皮生长因子+ 20 μg/L碱性成纤维细胞生长因子 + 条件培养液（细胞原代培养第7天的上清液的过滤液），进行单细胞克隆培养，传代的神经干细胞分成空白对照组、表皮生长因子组、脑源性神经生长因子组、表皮生长因子+脑源性神经生长因子组。空白对照组培养液为含体积分数0.1胎牛血清的DMEM/F12，其余3组培养液在此基础上分别加入各自对应的细胞因子培养1周，表皮生长因子浓度为20 μg/L，脑源性神经生长因子浓度为50 μg/L。③实验评估：传代后的克隆球进行神经干细胞免疫细胞化学染色鉴定。计数神经元特异性烯醇化酶阳性细胞率，检测神经干细胞向神经元的分化情况。 结果：①单细胞克隆培养后，克隆球细胞表达巢蛋白，诱导分化后神经元特异性烯醇化酶、胶质纤维酸性蛋白均呈阳性表达。②与空白对照组神经干细胞分化为神经元的比例比较，表皮生长因子组有所降低；脑源性神经生长因子组、表皮生长因子+脑源性神经生长因子组均明显提高（t=2.309~2.779，P < 0.05），且后者提高幅度尤为显著（t=2.309，P < 0.05）。 结论：表皮生长因子可以提高脑源性神经生长因子诱导成年大鼠脑海马神经干细胞向神经元分化的比例。     

脑源性神经生长因子基因转染对脊髓神经干细胞分化的影响

目的 研究BDNF基因转染小鼠脊髓源性NSCs向神经元分化情况.方法 选取体外培养E14小鼠胚胎脊髓来源NSCs,构建整合有BDNF基因的逆转录病毒载体,感染体外培养的NSCs,诱导其向神经元分化.采用免疫细胞化学方法鉴定,确定NSCs的分化比例.结果 转染后诱导分化24 h后可见部分细胞贴壁分化,48 h后转染细胞大部分贴壁.BDNF转染NSCs分化为神经元比例较未转染NSCs明显增高,差异有统计学意义(P＜0.05).结论 逆转录病毒载体介导BDNF基因转染NSCs可促进细胞分化,且分化多为神经元方向.

Abstract：

Objective To study the differentiation potential of mouse spinal cord derived neural stem cells (NSCs) into neurons after being transfected with BDNF gene in vitro. Methods Spinal cord derived NSCs from the E14 fetus mouse were isolated and cultured in vitro; the retrovirus containing pLXSN-BDNF gene was established and transfected into thc above NSCs, and thea, spinal cord derived NSCs were induced to be differentiated into neuron-like cells. Immunohistochemistry was employed to detect and calculate the ratio of differentiation of NSCs into neurons. Results The NSCs cultured in vitro partly adhered to the wall and differentiated within 24 h of transfection with BDNF gene, and most of the NSCs adhered to the wall differentiated within 48 h of transfection. The level of neurons from spinal cord derived NSCs modified by BDNF gene was markedly increased as compared with that that from normal spinal cord derived NSCs (P＜0.05). Conclusion NSCs transfected by retroviral pLXSN-BDNF can promote the cell differentiation. BDNF gene can increase greatly the percentage of neurons in the course of inducing the differentiation of mouse NSCs.     

Total saponins of Panax ginseng effects on proliferation and differentiation of human embryonic neural stem cells and in a Parkinson's disease mouse model

BACKGROUND:Total saponins of Panax ginseng(TSPG) exhibits neuroprotection against Parkinson's disease in the substantia nigra. OBJECTIVE:To investigate the effects of TSPG on human embryonic neural stem cells(NSCs) proliferation and differentiation into dopaminergic neurons using in vitro studies,and to observe NSC differentiation in a mouse model of Parkinson's disease,as well as behavioral changes before and after transplantation. DESIGN,TIME AND SETTING:In vitro neural cell biology trial and in vivo r...     

成人脑神经干细胞体内外增殖、分化和迁移研究

目的探索从成人脑组织获取的神经干细胞（成人-hNSCs）在体外的增殖能力、分化特性、以及在裸鼠颅内的存活、迁移及分化情况。方法分别留取癫痫患者手术切除的颞叶脑组织和10W左右人类自然流产胎儿纹状体组织,体外分离成单细胞悬液,无血清培养基培养、传代并诱导分化。软琼脂糖集落形成实验检测NSCs的增殖能力。免疫荧光法检测NSCs标志物神经上皮巢蛋白（Nestin）和诱导分化后神经元标志物13．tubllin以及神经胶质细胞标志物胶质纤维酸性蛋白（GFAP）的表达;利用动物立体定向仪将体外悬浮培养2W的人NSCs移植入裸鼠颅内,检测NSCs在裸鼠脑组织局部的存活、迁移和分化状况。结果成人-hNSCs集落形成能力较胚胎脑组织来源的NSCs（胎儿-hNSCs）明显减弱,免疫荧光染色显示分离的NSCs呈Nestin阳性,诱导分化后可见（β-tubllin和GFAP阳性的神经细胞,其中80％的细胞为GFAP阳性的星形胶质细胞,20％左右为β-tubllin阳性细胞。分别将成人-hNSCs和胎儿．hNSCs移植入裸鼠纹状体,1个月后,冰冻切片,荧光显微镜观察到来源于成人脑组织来源的NSCs仅见沿针道的近距离迁移,免疫荧光染色在成人-hNSCs移植裸鼠颅内只检测到GFAP阳性的星形胶质细胞。而胎儿-hNSCs可穿过针道,沿大脑廉向脑实质广泛迁移,免疫荧光染色能检测到GFAP和少量（β-tubllin阳性细胞。结论成人脑组织和胚胎纹状体组织中均能成功分离到神经前体细胞,而与胎儿．hNSCs相比,成人-hNSCs体外增殖能力、多向分化潜能和体内迁移能力都明显减弱。     

Bone morphogenetic proteins mediate cellular response and, together with Noggin, regulate astrocyte differentiation after spinal cord injury

Bone morphogenetic proteins (BMPs) play a critical role in regulating cell fate determination during central nervous system (CNS) development. In light of recent findings that BMP-2/4/7 expressions are upregulated after spinal cord injury, we hypothesized that the BMP signaling pathway is important in regulating cellular composition in the injured spinal cord. We found that BMP expressions were upregulated in neural stem cells (NSCs), neurons, oligodendrocytes and microglia/macrophages. Increased expression levels of pSmad1/5/8 (downstream molecules of BMP) were detected in neurons, NSCs, astrocytes, oligodendrocytes and oligodendroglial progenitor cells (OPCs). Active astrocytes which form the astroglial scar were probably derived from NSCs, OPCs and resident astrocytes. Since quiescent NSCs in the normal adult spinal cord will proliferate and differentiate actively into neural cells after traumatic injury, we proposed that BMPs can regulate cellular components by controlling NSC differentiation. Neurosphere culture from adult mouse spinal cord showed that BMP-4 promoted astrocyte differentiation from NSCs while suppressing production of neurons and oligodendrocytes. Conversely, inhibition of BMP-4 by Noggin notably decreased the ratio of astrocyte to neuron numbers. However, intrathecal administration of Noggin in the injured spinal cord failed to attenuate glial fibrillar acidic protein (GFAP) expression even though it effectively reduced pSmad expression. Noggin treatment did not block phosphorylation of Stat3 and the induction of GFAP in the injured spinal cord, suggesting that in addition to the BMP/Smad pathway, the JAK/STAT pathway may also be involved in the regulation of GFAP expression after spinal cord injury.     

多聚赖氨酸和明胶对神经干细胞增殖和分化的影响

摘要 背景：目前大鼠神经干细胞体外诱导分化的研究报道诸多,但其分化过程很难控制,很多实验的操作方法复杂,分化比率也很低。 目的：探索大鼠胚胎前脑神经干细胞体外原代及传代培养方法,并观察其分化规律。 方法：胎鼠在无菌条件下分离出前脑,制备单细胞悬液,以1×1011L-1接种于含N2的DMEM/F12培养基中培养,传代培养过程中加入BrdU,标记神经干细胞球。诱导分化实验分为多聚赖氨酸铺板组、明胶铺板组和无铺板组。采用体积分数20%胎牛血清刺激其分化。免疫细胞化学检测nestin、BrdU及在血清诱导条件下神经干细胞向神经细胞分化的能力。 结果与结论：细胞呈神经干细胞样生长,具有连续增殖能力,可以传代培养。传代神经球中的细胞均呈nestin阳性和BrdU阳性。多聚赖氨酸铺板组和明胶铺板组贴壁后分化为神经细胞能力强于无铺板组(P < 0.01)。多聚赖氨酸铺板组略强于明胶铺板组(P > 0.05)。神经谱系标记物神经胶质纤维酸性蛋白和微管相关蛋白2的免疫细胞化学结果均阳性。结果表明,大鼠胚胎前脑富含神经干细胞,其分化观察,多聚赖氨酸和明胶在诱导神经干细胞分化中作为细胞贴壁支持物提高分化细胞数量的作用,且多分化为星形胶质细胞。 关键词：多聚赖氨酸;神经干细胞;明胶;增殖分化;体外培养 doi:10.3969/j.issn.1673-8225.2010.47.004     

Nestin-EGFP transgenic mice: visualization of the self-renewal and multipotency of CNS stem cells

We generated transgenic mice carrying enhanced green fluorescent protein (EGFP) under the control of the nestin second-intronic enhancer (E/nestin:EGFP). Flow cytometry followed by in vitro assays revealed that in situ EGFP expression in the embryonic brain correlated with the mitotic index, the cogeneration of both neurons and glia, and the frequency of neurosphere formation in vitro. High-level EGFP expressors derived from embryos included a distinct subpopulation of cells that were self-renewable and multipotent, criteria that define neural stem cells (NSCs). Such cells were largely absent among lower-level or non-EGFP expressors, thereby permitting us to enrich for NSCs using EGFP expression level. In adults, although E/nestin:EGFP-positive cells included the NSC population, the frequency of neurosphere formation did not correlate directly with the level of EGFP expression. However, moderately EGFP-expressing cells in adults gained EGFP intensity when they formed neurospheres, suggesting embryonic and adult NSCs exist in different microenvironments in vivo.     

Neurosphere-derived neural cells show region-specific behaviour in vitro

Neurosphere cultures provide a useful model to study neural stem/progenitor cells (NSC/NPCs). The degree to which neurospheres (NS) retain their regional identity in vitro has, however, been questioned. Here, NS obtained from mouse embryonic cortex, striatum or spinal cord were compared after differentiation. Neurons from cortical NS formed well ordered clusters containing astrocytes, those from striatal NS formed an external ring at the borderof the astrocyte layer, whereas those from spinal cord NS spread radially like the astrocytes. Such in-vitro neural behaviour was region-specific and persisted in clonal conditions, providing evidence of the maintenance of positional cues in NS cultures.     

基质细胞衍生因子-1诱导神经干细胞靶向性迁移的实验研究

目的 观察基质细胞衍生因子-1(SDF-1)对神经干细胞(NSCs)迁移的影响.方法 由胚胎大鼠脑组织获取NSCs并进行传代培养和分化鉴定,使用流式细胞术检测NSCs纯度及SDF-1特异性受体CXCR4的表达情况,之后利用Blind-Well小室体外迁移体系观察不同浓度的SDF-1(0 ng/L、1 ng/mL、10 ng/mL、50 ng/mL、100 ng/mL、500 ng/mL和1000 ng/mL)对NSCs迁移数量的影响,并使用μ-载片观察SDF-1对NSCs迁移距离的影响.结果成功分离培养得到了能够在体外不断分裂增殖、具有多向分化潜能的NSCs,连续传3代后绝大部分细胞nestin表达阳性,nestin和CXCR4的共表达率达到80%左右.细胞趋化实验结果表明,SDF-1对NSCs有较强的趋化作用,随着SDF-1浓度的升高,发生迁移的细胞数量也随之增加,并于SDF-1浓度为500ng/mL时达到最高峰[(256.79±38.27)个细胞/每高倍视野].在μ-载片细胞生长通道两侧的SDF-1浓度梯度(500ng/mL→0ng/mL)作用下,由细胞克隆球迁出的细胞呈不对称分布,通常有更多的迁出细胞分布于趋化因子浓度较高的一侧,且该侧细胞的最大迁移距离也比对侧远.结论 SDF-1与其特异性受体CXCR4相巨作用能够诱导NSCs发生靶向性迁移.     

Migration and differentiation of neural progenitor cells from two different regions of embryonic central nervous system after transplantation into the intact spinal cord

Transplantation of in vitro-expanded neural stem cells (NSCs) is a potentially powerful tool to repair functions of the injured spinal cord. A prerequisite for the successful transplantation therapy is identification of optimized experimental parameters that can promote maximal survival, extensive migration and selective differentiation of the transplanted NSC population in the spinal cord. To this end, we evaluated the basic characteristics of NSC-like cells from two different donor sources, the embryonic hippocampus and spinal cord, after transplantation into the neonatal spinal cord. Proliferation and differentiation phenotypes of both NSC-like cells can be controlled by the concentration of fibroblast growth factor-2 (FGF-2) in vitro. Both NSC-like cells can survive within the environment of the intact neonatal spinal cord and showed extensive migratory behaviour shortly after transplantation. However, quantitative analysis revealed preferential migration of hippocampus-derived cells in the dorsal white matter. Both NSC-like cells showed restricted phenotype toward the oligodendroglial lineage after transplantation. Transplantation of the mixture of two cell types revealed selective survival of hippocampus-derived NSC-like cells. This study indicates the possibility of transplanting hippocampus-derived NSCs to supply the cell source for immature oligodendrocytes, which are thought to be essential for both the myelination and trophic support of regenerating axons in the dorsal white matter of the spinal cord.