E18胚胎大鼠皮层区离体神经元培养

神经元细胞体外培养,尤其来自中枢神经系统内的细胞,是研究神经退行性疾病发病机制、神经再生过程以及基因工程小鼠模型等重要的实验手段。E18胚胎大鼠皮层神经元体外培养技术,主要包括前期圆玻片处理、皮层分离、细胞消化、铺种以及更换培养基等。结果发现,该研究神经元细胞生长良好,可维持生长至少20天。在神经元形态方面,树突具有较多分支,轴突在不同细胞间形成连接。通过免疫染色和共聚焦显微镜成像,该研究可观察到树突棘结构。此外,对培养的神经元进行转染实验发现,转染后细胞状态良好,转染效率在10%左右。综上,神经元体外培养技术方法可以较好地培养神经元并能维持神经元正常发育生长。体外培养的神经元细胞可用于免疫组化、基因编辑以及实时成像研究。     

原代大鼠海马神经元的高效转染

用原代大鼠海马神经元为模型,对新型电转染方法Nucleofector^TM与脂质体DOTAP和Lipofectaimine^TM的转染效率和转染前后细胞存活率进行比较研究,探讨Nucleofector^TM的高效性与可靠性。从E18胎鼠海马中取出神经元进行体外培养,并用神经微丝(NF)抗体进行免疫细胞化学染色鉴定细胞类型。分别用DOTAP,Lipofectamine^TM and Nucleofector^TM包裹pCMV-eGFP质粒转染原代大鼠海马神经元。神经元的存活率用流式细胞仪检测。实验结果表明：DOTAP和Lipofectamine^TM的基因转染效率仅为1．55％和2．45％,而Nucleofector^TM的转染效率则超过20％;细胞转染前后的存活率在DOTAP组分别为98．37％和88．35％,Lipofectamine^TM组分别为98．37％和90．11％,而在Nucleofector^TM组中分别为98．37％和51．82％。上述实验数据表明：Nucleofector^TM转染技术能高效并安全地转染原代大鼠海马神经元,但死亡率较高。     

阿糖胞苷对大鼠海马神经元原代培养的影响

目的：探讨在大鼠海马神经元原代培养过程中,阿糖胞苷对培养神经元的影响。方法：将新生24 h大鼠,分离出海马组织,进行原代海马神经元培养,再将细胞分为阿糖胞苷组和对照组,阿糖胞苷组加入1μmol/L阿糖胞苷,通过检测神经元特异性标志物微管相关蛋白-2（Map-2）计算培养神经元的数量,通过台盼蓝染色法观察细胞的存活率。结果：培养第7天,阿糖胞苷组神经元数量为（11±3）个,对照组为（10±4）个,两组无明显差异;阿糖胞苷组神经元细胞在培养第14天时存活率为74%,培养第21天时存活率为49%,而对照组神经元14天时存活率为96%,21天存活率为88%,两组神经元存活率差异明显。结论：原代培养海马神经元时,阿糖胞苷对神经元产量及形态影响不明显,但是由于阿糖胞苷的毒性作用,明显缩短神经元的存活时间,影响长期培养神经元的存活率。     

原代培养的乙酰胆碱能神经元的表型表达与在体不同（英文）

为了进一步了解原代培养神经元技术是否可以用于建立可靠的乙酰胆碱能神经元体外培养细胞模型,该实验检测了分别培养自E18胎鼠基底前脑(basal forebrain, BF)和海马(hippocampus,HIP)原代培养神经元中的乙酰胆碱能神经元的标志物,同时比较了离体培养细胞与在体在相同脑区中乙酰胆碱能标志物表达的差异。使用免疫标记荧光方法,检测了来自E18胎鼠的基底前脑脑区和海马脑区的离体原代培养神经元中在DIV 3和DIV 21时间点上表达Ch AT和p75NTR(两种常用的胆碱能神经元标记物)的神经元的数量,分析其占总神经元数量的比例,并与E18胎鼠和成年小鼠相同脑区的在体组织切片中的结果相比较。结果显示, Ch AT和p75NTR均在来自基底前脑和海马的培养神经元的DIV 3和DIV 21中高比例表达。然而,虽然在E18胎鼠和成年小鼠的基底前脑的组织切片中有Ch AT和p75NTR的表达,但是在同时期的海马组织切片中并无Ch AT的表达,并且来自基底前脑和海马脑区的培养神经元中表达乙酰胆碱能神经元标志物的神经元数量占总神经元数量比例与在体并不一致。这些结果显示,乙酰胆碱能标志物在离体原代培养和在体中的表达状况可能存在不同。根据实验结果推测,在体外应用原代培养方法培养乙酰胆碱能标志物免疫阳性神经元可能并不是乙酰胆碱能神经元。除了通过免疫组织化学方法,还需要更多的技术和方法来鉴定培养细胞中的乙酰胆碱能神经元。     

家蚕原代细胞有丝分裂观察

在28℃,pH值6.4-6.8的条件下,用Grace培养基辅以20%的标准胎牛血清培养半消化法接种的家蚕晚期胚。原代培养细胞能够长期存活,观察到了家蚕原代培养过程中分化细胞的有丝分裂过程,发现了原代细胞分裂过程中赤道板的异常和染色体分离的异常现象;培养6个月和10个月的原代细胞分裂百分比分别为0.02±0.01和0.35±0.10,原代细胞异常的有丝分裂细胞百分比逐渐减少,分别为8.0±1.6和3.2±1.0。     

神经干细胞来源的神经元的诱导分裂

为探讨神经干细胞分化成熟的神经元是否能够分裂。实验取材于成年哺乳动物,将神经干细胞体外培养8d后,诱导分化为神经元,然后进一步诱导其分裂。采用连续摄影与NF-160免疫细胞化学方法检测神经元的分裂过程,同时运用PCNA NF-160(或Chat、GABA、GAD)的免疫双标记证明分裂神经元是否为成熟神经元。将神经干细胞体外诱导分化培养8d,直至分化神经元外形成熟,进而加入EGF与bFGF诱导分裂。诱导分裂2d后,观察到有神经元样细胞分裂;同一区域内神经元样细胞的数量不断增加,表现为NF-160阳性。连续拍摄了神经元样细胞的分裂过程,分裂完成后的细胞同样表现为NF-160抗体反应阳性。PCNA NF-160(或Chat、GABA、GAD)的免疫双标记结果显示,一些细胞的胞浆显示为棕色的同时细胞核显示为黑色。结果提示,在一定的条件下,先前所认为的终末分化神经元可以重新进入细胞周期,成熟神经元仍然可以进行分裂增殖和自我更新。     

SD大鼠视网膜小胶质细胞原代培养方法的改良

目的对经典的原代视网膜小胶质细胞体外纯化培养方法进行简单的改良以提高细胞产量。方法在视网膜小胶质细胞原代培养过程中以McCarthy等的经典方法为基础,寻找适当的初始种植密度,并在初次振荡分离后继续培养以获得多次产出,使用免疫细胞化学染色方法进行小胶质细胞纯度鉴定。结果视网膜小胶质细胞原代培养最宜初始种植密度为1×106/mL,多次分离纯化获得的视网膜小胶质细胞均达到97%以上的纯度。结论视网膜小胶质细胞原代培养过程中,以适当的初始种植密度和多次振荡分离方法可在保证有效纯度的基础上提高细胞产量。     

SD大鼠乳鼠皮层神经元细胞原代培养模型的建立及鉴定

摘要 目的：探讨SD大鼠乳鼠皮层神经元细胞原代培养方法,并鉴定其培养效果,以期建立一种生物学功能良好的体外细胞实验模型。方法：取出生24 h的SD大鼠乳鼠,分离出大脑皮层,在胰酶消化之前先进行离心,然后将胰酶消化后多次离心得到的细胞悬液接种于L-多聚赖氨酸包被的培养皿和共聚焦皿中,以加B27的Neurobasal-A培养基进行神经元细胞的原代培养,倒置显微镜下观察培养细胞的生长状态;通过免疫荧光组化的方法采用神经元标记物MAP-2进行神经元纯度的鉴定;在导入Fluo4-AM的原代神经元细胞,观察电刺激后胞内钙离子信号的变化,以验证神经元细胞的生理状态。结果：采用此方法培养的神经元细胞紧密贴壁、分散均匀、状态良好,神经元细胞周围突起相互连接形成网络;经MAP-2免疫荧光组化技术鉴定神经元的纯度达到95%以上;胞内钙离子信号的变化提示所培养的神经元具有良好的生物学功能。结论：该方法能获得纯度较高并且生物学功能良好的原代培养的SD大鼠乳鼠皮层神经元细胞。     

大鼠骨髓基质干细胞的分离培养与向神经元样细胞诱导分化的实验研究

目的 探讨大鼠骨髓基质干细胞的提取、分离培养和体外扩增的最佳条件,研究其在体外培养中定向诱导分化为神经元样细胞的可能。方法 通过密度梯度离心和贴壁培养法从成年大鼠骨髓中分离骨髓基质干细胞,进行培养扩增,观察其生长特性;用2-巯基乙醇(β-mercaptoethanol,β-ME)对传代细胞诱导分化,并通过免疫细胞化学染色鉴定分化细胞的类型。结果 原代培养时形成由基质干细胞组成的细胞集落,细胞集落14d时接近融合,传代后,细胞体积变大,约5～7d传代一次。β-ME诱导后,70％以上的细胞在形态上呈神经元样,免疫细胞化学染色呈NSE阳性,GFAP阴性,说明诱导分化的细胞为神经元,而不是星形胶质细胞。结论 骨髓基质干细胞在体外培养条件下生长良好,并可连续传代;在β-ME作用下可被诱导分化为神经元样细胞。     

Visualization of Mitochondrial Membrane Dynamics in Primary Cultured Neurons by Cryo-electron Tomography

本文利用冷冻电子断层扫描成像技术研究了原代培养海马神经元中线粒体膜的动态变化. 线粒体的分裂与融合是线粒体膜动态变化的主要方式，也是维持线粒体功能正常的重要手段. 线粒体分裂的机制研究以往是基于荧光标记的光学显微成像，由于分辨率的限制并不能直接观察到线粒体分裂过程中的超微结构特征. 冷冻电子断层成像通过尽可能保持样品生理状态从而获得更真实的结构信息. 本文通过对原代海马神经元中的自发性线粒体膜动态变化的成像，发现中央分裂和外周分裂的线粒体都与内质网在空间上存在一定的相互作用，内质网通过缠绕在线粒体分裂位点来参与分裂过程. 值得注意的是，还发现部分线粒体会出现线粒体外膜与内膜分离的现象，形成“无基质”的特殊区域. 这些可能都表明了线粒体质量控制的方式.     

Embryonic stem cell-derived neural progenitors as non-tumorigenic source for dopaminergic neurons

AIM:To find a safe source for dopaminergic neurons,we generated neural progenitor cell lines from human embryonic stem cells.METHODS:The human embryonic stem(hES)cell line H9 was used to generate human neural progenitor(HNP)cell lines.The resulting HNP cell lines were differentiated into dopaminergic neurons and analyzed by quantitative real-time polymerase chain reaction and immunofluorescence for the expression of neuronal differentiation markers,including beta-III tubulin(TUJ1)and tyrosine hydroxylase(TH).To assess the risk of teratoma or other tumor formation,HNP cell lines and mouse neuronal progenitor(MNP)cell lines were injected subcutaneously into immunodeficient SCID/beige mice.RESULTS:We developed a fairly simple and fast protocol to obtain HNP cell lines from hES cells.These cell lines,which can be stored in liquid nitrogen for several years,have the potential to differentiate in vitro into dopaminergic neurons.Following day 30 of differentiation culture,the majority of the cells analyzed expressed the neuronal marker TUJ1 and a high proportion of these cells were positive for TH,indicating differentiation into dopaminergic neurons.In contrast to H9 ES cells,the HNP cell lines did not form tumors in immunodeficient SCID/beige mice within 6 mo after subcutaneous injection.Similarly,no tumors developed after injection of MNP cells.Notably,mouse ES cells or neuronal cells directly differentiated from mouse ES cells formed teratomas in more than 90%of the recipients.CONCLUSION:Our findings indicate that neural progenitor cell lines can differentiate into dopaminergic neurons and bear no risk of generating teratomas or other tumors in immunodeficient mice.     

Control of neuronal morphology and connectivity: Emerging developmental roles for gap junctional proteins

Recent evidence indicates that gap junction (GJ) proteins can play a critical role in controlling neuronal connectivity as well as cell morphology in the developing nervous system. GJ proteins may function analogously to cell adhesion molecules, mediating cellular recognition and selective neurite adhesion. Moreover, during synaptogenesis electrical synapses often herald the later establishment of chemical synapses, and thus may help facilitate activity-dependent sculpting of synaptic terminals. Recent findings suggest that the morphology and connectivity of embryonic leech neurons are fundamentally organized by the type and perhaps location of the GJ proteins they express. For example, ectopic expression in embryonic leech neurons of certain innexins that define small GJ-linked networks of cells leads to the novel coupling of the expressing cell into that network. Moreover, gap junctions appear to mediate interactions among homologous neurons that modulate process outgrowth and stability. We propose that the selective formation of GJs between developing neurons and perhaps glial cells in the CNS helps orchestrate not only cellular synaptic connectivity but also can have a pronounced effect on the arborization and morphology of those cells involved.     

Fibronectin associated with the glial component of embryonic brain cell cultures

In a basic approach to investigations of neuronal–glial interactions during both normal brain development and its pathogenesis, embryonic brain cell populations were fractionated into purified neuronal and glial components. Using separation procedures based on differential adhesion and cytotoxicity, the isolated neuronal and glial phenotypes could be identified by distinct morphological and biochemical characteristics, including the visualization of glial fibrillary acid protein (GFA) within glial cells in immunohistochemical assays with monospecific anti-GFA serum. When unfractionated cerebrum cells dissociated from 10-day chick or 14-day mouse embryos were plated as monolayers and cultured for 1-14 days, monospecific antiserum against fibronectin (LETS glycoprotein) was found to react with many, but not all, of the cells as revealed by indirect immunofluorescence microscopy. The isolated neuronal and glial components of these populations were used to determine whether the appearance of membrane-associated fibronectin was characteristic of one cell type or the other, or both, and if neuronal–glial cell interaction was required for its expression. It was found that the surfaces of glial cells, completely isolated from neurons, showed an intense fluorescent reaction to the anti-fibronectin serum. In contrast, the purified neuronal cultures showed no fluorescence with either the anti-GFA or anti-fibronectin sera. These results demonstrate fibronectin as a cell surface protein associated primarily with glial cells and independent of neuronal–glial cell interaction for its expression. Furthermore, the results indicate that the fibronectin observed on glial cell surfaces in these cultures is produced endogenously and is not due to the preferential binding of fibronectin present in the culture medium. The role of fibronectin as an adhesive molecule in neuronal–glial interactions is discussed.     

Differentiation of embryonic chick sympathetic neurons in vivo: ultrastructure,and quantitative determinations of catecholamines and somatostatin

Summary The ultrastructural and transmitter development of lumbar sympathetic ganglia was studied in embryonic day-6 through-18 chick embryos. At embryonic day 6, ganglia are populated by two morphologically distinct types of neuronal cells and Schwann cell precursors. The neuronal populations basically comprise a granule-containing cell and a developing principal neuron. Granule-containing cells have, an irregularly shaped or oval nucleus with small clumps of chromatin attached to the inner nuclear membrane and numerous large (up to 300 nm) membrane-limited granules. Developing principal neurons display a more rounded vesicular nucleus with evenly distributed chromatin, prominent nucleoli, more developed areas of Golgi complexes, and rough endoplasmic reticulum and large dense-core vesicles up to 120 nm in diameter. There are granule-containing cells with fewer and smaller granules which still display the nucleus typical for granule-containing cells. These granule-containing cells may develop toward developing principal neurons or the resting state of granule-containing cells found in older ganglia. Both granule-containing cells and developing principal neurons proliferate and can undergo degeneration. At embryonic day 9 there are far more developing principal neurons than granule-containing cells. Most granule-containing cells have very few granules. Mitotic figures and signs of cell degeneration are still apparent. Synapse-like terminals are found on both developing principal neurons and granule-containing cells. Ganglionic development from embryonic day 11 through 18 comprises extensive maturation of developing principal neurons and a numerical decline of granule-containing cells. Some granule-containing cells with very few and small granules still persist at embryonic day 18. The mean catecholamine content per neuron increases from 0.044 femtomol at embryonic day 7 to 0.22 femtomol at embryonic day 15. Concomitantly, there is a more than 6-fold increase in tyrosine hydroxylase activity. Adrenaline has a 14% share in total catecholamines at embryonic day 15. Somatostatin levels are relatively high at embryonic day 7 (1.82 attomol per neuron) and are 10-fold reduced by embryonic day 15. Our results suggest the presence of two morphologically distinct sympathetic neuronal precursors at embryonic day 6: one with a binary choice to become a principal neuron or to die, the other one, a granule-containing cell, which alternatively may develop into a principal neuron, acquire a resting state or die.     

Insights into the regulation of neuronal viability by nucleophosmin/B23

The vastness of the neuronal network that constitutes the human brain proves challenging when trying to understand its complexity. Furthermore, due to the senescent state they enter into upon maturation, neurons lack the ability to regenerate in the face of insult, injury or death. Consequently, their excessive death can be detrimental to the proper functioning of the brain. Therefore, elucidating the mechanisms regulating neuronal survival is, while challenging, of great importance as the incidence of neurological disease is becoming more prevalent in today’s society. Nucleophosmin/B23 (NPM) is an abundant and ubiquitously expressed protein that regulates vital cellular processes such as ribosome biogenesis, cell proliferation and genomic stability. As a result, it is necessary for proper embryonic development, but has also been implicated in many cancers. While highly studied in the context of proliferative cells, there is a lack of understanding NPM’s role in post-mitotic neurons. By exploring its role in healthy neurons as well as its function in the regulation of cell death and neurodegeneration, there can be a better understanding of how these diseases initiate and progress. Owing to what is thus far known about its function in the cell, NPM could be an attractive therapeutic target in the treatment of neurodegenerative diseases.     

The fine structure of continuous human neuroblastoma lines SK-N-SH,SK-N-BE(2), and SK-N-MC

Summary Cell cultures of the continuous human neuroblastoma lines SK-N-SH, SK-N-BE(2), and SK-N-MC at exponential and stationary growth phase have been examined by electron microscopy. At the level of fine structure these cells did not show typical neuronal differentiation such as extensive granular endoplasmic reticulum or neurites with microtubules and neurofilaments. Instead they were characterized by abundant free ribosomes, moderate Golgi complexes, and usually scant granular endoplasmic reticulum, features similar to the fine structure of early normal embryonic autonomic neurons. However, in several respects appearance of differentiated features of the neuroblastoma cells did not follow the pattern observed for normal neurons, suggesting noncoordinate, expression of neuronal phenotypic properties. First, an occasional neuroblastoma cell had as extensive granular endoplasmic reticulum as would be found at later stages in normal developing neurons. Second, the cellular processes of these neuroblastoma cells did not have the fine structure of developing or mature axons in vivo. Third, few dense core vesicles were found in SK-N-SH and SK-N-BE(2), though these organelles are numerous in early normal adrenergic neurons and the adrenergic character of these two lines is apparent from other studies that have demonstrated expression of neurotransmitter synthesizing enzymes (SK-N-MC is cholinergic). The fine structural characterization of these continuous human neuroblastoma cell lines will allow this parameter to be utilized with other approaches in future experimental studies. This work was supported by PSC-BHE Research Award 11612 from the City University of New York and in part by the National Cancer Institute Core Grant CA-08748 to the Sloan-Kettering Institute. E. N. B. was the recipient of a predoctoral fellowship under USPHS Training Grant GM02050.     

NGF 对大鼠胚胎中脑神经细胞体外增殖和分化的影响

目的:探讨神经生长因子(nerve growth factor,NGF)对大鼠胚胎中脑神经细胞体外增殖和分化的影响。方法:在体外分离培养大鼠胚胎中脑神经细胞的培养液中加入不同浓度(10、50、100、200ng/ml)的NGF,培养不同时间,以不加神经营养因子的细胞为对照组,通过MTT法检测细胞活性,神经元特异性烯醇化酶免疫细胞荧光技术鉴定神经细胞,光镜下形态学观察各组大鼠中脑神经细胞体外增殖和分化情况。结果:胚胎中脑神经细胞胞体增大、突起延长且有丰富的神经纤维连结成网络状,细胞集落数增加,显示出剂量-效应关系。结论:一定剂量的NGF能促进大鼠中脑神经细胞分化和增殖,增强其活性。     

Mature neurons: equipped for survival

Neurons completely transform how they regulate cell death over the course of their lifetimes. Developing neurons freely activate cell death pathways to fine-tune the number of neurons that are needed during the precise formation of neural networks. However, the regulatory balance between life and death shifts as neurons mature beyond early development. Mature neurons promote survival at all costs by employing multiple, often redundant, strategies to prevent cell death by apoptosis. This dramatic shift from permitting cell death to ensuring cellular survival is critical, as these post-mitotic cells must provide neuronal circuitry for an organism''s entire lifetime. Importantly, as many neurodegenerative diseases afflict adult neuronal populations, the survival mechanisms in mature neurons are likely to be either reversed or circumvented during neurodegeneration. Examining the adaptations for inhibiting apoptosis during neuronal maturation is key to comprehending not just how neurons survive long term, but may also provide insight for understanding how neuronal toxicity in various neurodegenerative diseases may ultimately lead to cell death.