活化小胶质细胞致星形胶质细胞激活

目的探讨活化小胶质细胞培养液对星形胶质细胞的影响。方法 LPS激活原代培养小胶质细胞,采用活化的小胶质细胞条件培养液刺激星形胶质细胞,观察星形胶质细胞GFAP及IL-1β和TNFα的表达。结果 LPS刺激后,小胶质细胞OX42表达量上升,IL-1β和TNFα的表达量增高;小胶质细胞条件培养液可致星形胶质细胞激活,GFAP表达量上升,IL-1β和TNFα的表达量增加。结论活化小胶质细胞的条件培养液可致星形胶质细胞激活,激活的小胶质细胞和星形胶质细胞表达前炎症介质IL-1β和TNFα。     

中枢神经星形胶质细胞的研究

中枢神经星形胶质细胞的研究肖芷江华西医科大学成都６１００４１一、形态特征：胞体小，具有细长而分支的突起，突起末端扩大成脚板于邻近的毛细血管壁上。它们可分为纤维性和原浆性两型。前者多分布于脑和脊髓的白质，细胞内富含原纤维，突起长而分支少；后者多分布于脑...     

星形胶质细胞谱系及星形细胞瘤起源的研究

各种神经胶质细胞中数目最多、分布最广的星形细胞担负了神经胶质细胞的大部分功能。根据对两种神经组织标志物─ＧＦＡＰ、Ａ－２Ｂ－５抗体的反应不同，将星形细胞分为１型（ＧＦＡＰ＋Ａ－２Ｂ－５－）和２型（ＧＦＡＰ＋、Ａ－２Ｂ－５＋）。研究指出两型星细胞来源于不同祖细胞，而存在两个谱系，星形细胞胶质瘤与星形细胞具有同样的谱系源。对小胶质细胞在星形细胞发生和分化中的作用亦予以阐述。     

星形胶质细胞在帕金森病发病机制中的作用

帕金森病是中老年人常见的中枢神经系统变性疾病。星形胶质细胞可能参与了其发病过程,一方面,它可以通过释放神经营养因子、谷胱甘肽等保护多巴胺能神经元,在帕金森病中发挥保护作用;另一方面,它也可能通过释放一些促炎症因子而推动帕金森病的发生和发展。     

星形胶质细胞的神经干细胞特性

胶质细胞是脑内数量最多的细胞,它与神经元之间的相互联系是在发育期就精确建立的。不同神经元的功能已有较深入的研究,与之相比,胶质细胞仍是非常神秘的细胞,特别是星形胶质细胞,除了对神经元提供重要的结构、代谢、营养支持外,它与神经元之间复杂的相互联系仍不清楚。本文将对星形胶质细胞作为神经干细胞／祖细胞这一最新发现作一综述。     

Fasudil对实验性自身免疫性脑脊髓炎小鼠小胶质细胞和星形胶质细胞的作用

目的:确认法舒地尔(Fasudil)对实验性自身免疫性脑脊髓炎(EAE)的治疗效果,观察法舒地尔对小胶质细胞和星形胶质细胞的作用.方法:成年雌性C57BL/6小鼠用MOG35-55肽免疫制作慢性EAE模型,分别随机在免疫后第3天(Fasudil早期治疗组)和发病时给予Fasudil(Fasudil晚期治疗组),以同样方式给予生理盐水作为对照.观察临床症状和体质量变化;采用免疫荧光组织化学染色、Western blot 法检测脊髓小胶质细胞和星形胶质细胞iNOS和p-NF-κB/p65的表达,ELISA测定脊髓匀浆中IL-1β和TNF-α水平.结果:Fasudil推迟EAE起病,减轻EAE症状,抑制脊髓中小胶质细胞iNOS以及星形胶质细胞p-NF-κB/p65表达,并伴随炎性因子IL-1β和TNF-α释放降低.结论:Fasudil可抑制EAE小鼠小胶质细胞和星形胶质细胞炎性分子的释放.     

福尔马林炎性痛对星形胶质细胞活化的影响

目的:研究福尔马林炎性痛对中枢神经系统星形胶质细胞活化的影响。方法:成年健康SD大鼠,随机分为正常组、实验组和生理盐水组;实验组左后足底注射4%福尔马林100μl建立炎性痛模型,并分为注射后30 min、60 min、3 h、6 h、12h、1 d、3 d、7 d、15 d等9个时间点。组织常规石蜡包埋,应用免疫组织化学显色和Image J图像分析检测星形胶质细胞标志物GFAP在脊髓、脑和海马内的表达和分布。结果:正常组和生理盐水组脊髓、脑和海马内GFAP有少量表达;实验组脊髓、脑和海马内的G-FAP阳性细胞数和光密度值在60 min~3 h开始增加,1~3 d达到峰值,随后开始下降,15 d降至正常水平,阳性细胞呈现增殖和肥大两种形态学改变。结论:福尔马林炎性痛大鼠脊髓、脑和海马内星形胶质细胞被激活,可能参与炎性痛形成、维持与恶化。     

氨对星形胶质细胞超微结构的影响

目的：在体外实验条件下观察氨对星状胶质细胞超微结构的影响。材料与方法：用ＮＨ４Ｃｌ造成高高ＮＨ４环境，对体外培养之星形胶质细胞的形态变化进行了超微结构观察。结果：高ＮＨ４环境下，星菜胶质细胞首先表现出损伤性变化，细胞电子密度降低，线粒体、内质网等细胞器肿胀，在胞质内形成许多单位膜包绕的电子密度降低的空泡区域，以后随着氨浓度加大或／和氨作用的时间延长，细胞内成份开始出现增生修复现象，次级溶酶体数量增     

雷公藤甲素对LPS诱导的神经炎症中星形胶质细胞和小胶质细胞激活的抑制作用

选用健康成年雄性SD大鼠,用不同剂量的雷公藤甲素[10、25、50μg/(kg·d)]预处理5d后,海马注射内毒素(LPS,4μg)24h。采用免疫组织化学和荧光组织化学方法观察海马内星形胶质细胞标记物胶质纤维酸性蛋白(GFAP)和小胶质细胞标记物蓖麻凝集素-1(RCA-1)表达的变化。结果显示:与生理盐水对照组比较,LPS注射引起注射部位GFAP表达增加,RCA-1阳性细胞增多、变大。而雷公藤甲素[50μg/(kg·d)]可明显下调LPS诱导的GFAP和RCA-1的表达,其抑制程度与药物剂量呈正相关。本研究结果提示,雷公藤甲素对海马内LPS诱导的星形胶质细胞和小胶质细胞的激活有明显的抑制作用。     

NH+4对星状胶质细胞谷氨酰胺代谢的影响

目的：了解体外培养状态下,ＮＨ４＋对脑星准确无误胶质细胞谷氨酰胺代谢的影响。方法;将不同浓度ＮＨ４ＣＩ加入培养液作用不同的时间,分别收集细胞及上清进行测定。结果：ＮＨ４＾＋作用后,星状胶质细胞谷氨酰胺合成酶活性啬细胞内及上清液内谷氨酰胺含量啬且在一定程度上随着ＮＨ４＾＋氨的浓度的增大而增加。然而,妾ＮＨ４＾＋２作用时间达到一定时限（７２ｈ）后,酶的活性及细胞内谷氨酰胺的量不再增加,甚至有所下降或减     

Kainate receptors in primary afferents to the rat gracile nucleus

The expression of metabotropic glutamate receptor 8 (mGluR8) was studied in the rat hippocampus after pilocarpine-induced status epilepticus (APISE) by light immunohistochemistry and immunoelectron microscopy. At 1 day APISE, mGluR8 immunoreactivity was up-regulated in the entire molecular layer of the dentate gyrus. At 7 days APISE, mGluR8 immunoreactive cells began to appear in the stratum lacunosum moleculare of CA1, and by day 31, they were seen in all layers of CA1. By electron microscopy and double labelling study, the mGluR8 immunoreactive cells were identified as astrocytes. The present novel finding of induced expression of mGluR8 in astrocytes APISE suggests that it may be linked to gliosis.     

缺氧对星形胶质细胞表达P450 2C11 mRNA的影响

目的:观察缺氧和/或谷氨酸对星形胶质细胞细胞色素P4502C11mRNA表达的影响, 探讨大脑星形胶质细胞在缺氧性脑血管扩张反应中的作用。方法:取新生Wistar大鼠大脑皮层星形胶质细胞作原代、传代培养后, 分为4组:①对照组;②谷氨酸组;③缺氧组;④缺氧+谷氨酸组。每一组包括5个时点:0h、3h、6h、12h、24h(以缺氧后开始记时).于②和④组加入100μmol/L的L-谷氨酸。③和④组用95%N²/5%CO²的混合气体条件培养。提取总RNA, 用RT-PCR技术检测P4502C11mRNA的表达量。结果:①在静息状态下, 星形胶质细胞表达一定量的P4502C11mRNA;②对照组和缺氧组各时点星形胶质细胞P4502C11mRNA的表达量无显著差异;③谷氨酸组P4502C11mRNA6h显著增高, 以后更为显著(24h内);④缺氧+谷氨酸组P4502C113h显著增高, 以后更为显著(24h内);⑤缺氧+谷氨酸组增高的幅度显著高于谷氨酸组。结论:缺氧和谷氨酸协同作用, 促使体外培养的星形胶质细胞P4502C11mRNA表达增强, 后者催化花生四烯酸生成环氧二十烷三烯酸, 这可能是缺氧性脑血管扩张的重要机制之一。     

Distribution of peptide transporter PEPT2 mRNA in the rat nervous system

 The signaling action of neuropeptides in the brain is terminated by breakdown through extracellular peptidases and subsequent removal of the peptide fragments from the extracellular fluid via specific transporter proteins. Here we describe the anatomical distribution in the rat nervous system of the recently isolated high affinity peptide transporter PEPT2. Using nonisotopic in situ hybridization we demonstrate that PEPT2 mRNA is expressed in brain by astrocytes, subependymal cells, ependymal cells and epithelial cells of choroid plexus. Furthermore, PEPT2 is expressed in retina by Müller cells and in dorsal root ganglia by satellite cells. The mRNA levels of PEPT2 in astrocytes are moderate and relatively homogenous throughout the brain except for an area in ventral forebrain where PEPT2 levels are below average. PEPT2 mRNA expression is weakly upregulated in reactive astrocytes that were stimulated through an injection of the glutamatergic neurotoxin quinolinic acid. These data suggest that removal of neuropeptide fragments from brain extracellular fluid occurs via PEPT2 expressed in astrocytes, ependymal cells and choroid plexus epithelial cells. Accepted: 26 October 1998     

Morphology and functions of astrocytes cultured on water-repellent fractal tripalmitin surfaces

In the brain, astrocytes play an essential role with their multiple functions and sophisticated structure, as surrounded by a fractal environment which has not been available in our traditional cell culture. Water-repellent fractal tripalmitin (PPP) surfaces can imitate the fractal environment in vivo, so the morphology and biochemical characterization of astrocytes on these surfaces are examined. Water-repellent fractal PPP surface can induce astrocytes to display sophisticated morphology with smaller size of cell area, longer and finer filopodium-like processes, and higher morphological complexity. The super water-repellent fractal PPP surface with water contact angle of 150°∼160° produces the maximal effects compared with other surfaces at lower water contact angles. The trends of characteristic protein expression, including that of nestin, vimentin, GFAP and glutamine synthetase, for astrocytes cultured on super water-repellent fractal PPP surfaces approximate more to in vivo pattern. The super water-repellent PPP surface also render astrocytes to perform more pronounced promotion of neurogenesis by increasing the release of nerve growth factor in a co-culture system. Altogether, our results suggest that the super water-repellent fractal PPP surface facilitates the astrocytes to mimic their in vivo performance, thus provides a closer-to-natural culture environment for experimental assessment of glial structure and functions.     

Stimulating effect of neutral proteases on cells in vitro

Some results concerning the stimulatory effect of proteases on lymphocytes and other cells such as Hela cells and fibroblasts are evaluated. Preliminary evidence indicates that such stimulating factors are indeed released from cells during phagocytosis and can be inhibited by aprotinin. The potential role of such proteases in inflammation is discussed.Supported by grant of the Swiss National Fund for Scientific Research.     

Photolytic flash-induced intercellular calcium waves using caged calcium ionophore in cultured astrocytes from newborn rats

Waves of elevated intracellular free calcium that propagate between neighboring astrocytes are important for the intercellular communication between astrocytes as well as between neurons and astrocytes. However, the mechanisms responsible for the initiation and propagation of astrocytic calcium waves remain unclear. In this study, intercellular calcium waves were evoked by focal photolysis of a caged calcium ionophore (DMNPE-caged Br A23187) in cultured astrocytes from newborn rats. The focal photolysis of the caged compound resulted in the increase in intracellular calcium in a single astrocyte, and this increase then propagated to neighboring astrocytes. We also analyzed the spatiotemporal characteristics of the intercellular calcium waves, and estimated the propagation pathways for them. The method using a caged calcium ionophore described in this study provides a new in vitro model for the analysis of intercellular calcium waves.     

Copper-treatment increases the cellular GSH content and accelerates GSH export from cultured rat astrocytes

To test whether copper exposure affects astroglial glutathione (GSH) metabolism, we have exposed astrocyte-rich primary cultures with copper chloride in concentrations of up to 30 μM and investigated cellular and extracellular GSH contents. Cultured astrocytes accumulated copper in a concentration-dependent manner thereby increasing the specific cellular copper content within 24 h up to sevenfold. The increase in the cellular copper content was accompanied by a proportional increase in the specific cellular GSH content that reached up to 165% of the values of cells that had been incubated without copper, while the low cellular content of GSH disulfide (GSSG) remained unaltered in copper-treated cells. Also the rate of GSH export was significantly increased after copper exposure reaching up to 177% of control values. The export of GSH from control and copper-treated astrocytes was lowered by more than 70%, if cells were incubated in presence of the multidrug-resistance protein (Mrp) 1 inhibitor MK571 or at a low incubation temperature of 4 °C. These data demonstrate that copper accumulation stimulates GSH synthesis and accelerates Mrp1-mediated GSH export from cultured astrocytes. These processes are likely to contribute to the resistance of astrocytes against copper toxicity and could improve the supply of GSH precursors from astrocytes to neurons.     

体外血小板活化因子对神经元和星形胶质细胞的作用

目的：研究血小板活化因子（PAF）对神经元活力及星形胶质细胞胶质纤维酸性蛋白（GFAP）表达的影响。 方法： 分别取BALB/c胎鼠和新生小鼠大脑皮层，纯化培养神经元和星形胶质细胞，设正常对照组和实验组，实验组中分别加入4、8和16 μmol/L的PAF并分别作用4 h、24 h和72 h,用MTT法和免疫组织化学方法测定神经元活力和星形胶质细胞表达GFAP的平均灰度值。 结果： PAF作用后，神经元活力降低；星形胶质细胞数量减少，但存活细胞GFAP表达增加。两者均呈浓度依赖关系。 结论： PAF不仅直接作用于神经元，且可通过作用于星形胶质细胞间接影响神经元的存活。     

Determining the oxidation states of manganese in NT2 cells and cultured astrocytes

Excessive brain manganese (Mn) can produce a syndrome called “manganism”, which correlates with loss of striatal dopamine and cell death in the striatum and globus pallidus. The prevalent hypothesis for the cause of this syndrome has been oxidation of cell components by the strong oxidizing agent, Mn³⁺, either formed by oxidation of intracellular Mn²⁺ or transported into the cell as Mn³⁺. We have recently used X-ray absorption near edge structure spectroscopy (XANES) to determine the oxidation states of manganese complexes in brain and liver mitochondria and in nerve growth factor (NGF)-induced and non-induced PC12 cells. No evidence was found for stabilization or accumulation of Mn³⁺ complexes because of oxidation of Mn²⁺ by reactive oxygen species in these tissues. Here we extend these studies of manganese oxidation state to cells of brain origin, human neuroteratocarcinoma (NT2) cells and primary cultures of rat astrocytes. Again we find no evidence for stabilization or accumulation of any Mn³⁺ complex derived from oxidation of Mn²⁺ under a range of conditions.