星形胶质细胞

<正> 本文着重讨论星形胶质细胞在位置和功能上与中枢神经系统细胞外隙的关系。目前,一般来说,对少突胶质细胞和小胶质细胞的功能已颇为明确(髓鞘形成,吞噬作用)。但在中枢神经系统的总体积上占有较大比重的星形胶质细胞,其功能问题却     

小胶质细胞对星形胶质细胞活化影响的实验研究

反应性星形胶质活化是中枢神经系统(CNS)在许多病理情况下常见的反应,但其发生机理尚有待阐明。近年研究发现一些细胞因子能引起星形胶质细胞的活化,我们及其它一些实验室的工作证实在多种损伤后小胶质细胞反应最早,是CNS损伤急性阶段主要应答细胞;故有文献提出反应性胶质化是一种后发现象,受小胶质细胞分泌产物的调节。本实验应用细胞培养技术观察了小胶质细胞条件培养液对星形胶质细胞的影响。取新生大鼠大脑皮层,参考Giulian(86)与McCarthy(80)等的方法进行星形胶质细胞与小胶质细胞的分离纯化培养;传代2次的星形胶质细胞种植于多孔…     

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     

马桑内酯对星形胶质细胞细胞周期变化的影响

胶质细胞细胞周期的改变,会导致细胞自身功能的改变．从而引发一些疾病的形成。研究致痫时星形胶质细胞细胞周期的变化,可能对癫痫的形成机制提供新的思路。用马桑内酯（CL）刺激体外纯化培养的海马星形胶质细胞2、4、6、8h后．应用流式细胞技术测定越形胶喷细胞细胞周期各时期细胞的变化．结果显示：CL作用4h后,G1期细胞数较对照组和2h组明显下降（P〈0．05）,S期和G2＋M期比对照组明显增高（P〈0．05）。同时细胞凋亡也随着时间的延长而增加（P〈0．05）。本实验结果提示致痫时星形胶质细胞细胞周期会发生改变．即细胞由G1／G0期向S和G2＋M期快速转化。     

白藜芦醇对星形胶质细胞ATP释放的影响

目的研究白藜芦醇对体外培养的星形胶质细胞牵拉损伤后三磷酸腺苷（ATP）释放的影响,探索其对中枢神经保护作用的可能机制。方法采用不同剂量的白藜芦醇与星形胶质细胞共同培养12h后,进行牵拉损伤,检测不同实验组星形胶质细胞内、外ATP含量,并进行乳酸脱氢酶（LDH）漏出量的测定。结果牵拉损伤使星形胶质细胞分泌ATP明显增加,相反细胞内ATP含量明显下降（P〈0．05）;1μmol白藜芦醇能够使星形胶质细胞损伤后ATP分泌进一步增加（P〈0．05）;而100μmol白藜芦醇能减少损伤后ATP分泌（P〈0．05）。对细胞进行LDH漏出量的检测发现,牵拉损伤能够使星形胶质细胞的LDH漏出量增加（P〈0．05）,1μmol白藜芦醇进一步加剧了LDH漏出（P〈0．05）,100μmol白藜芦醇能够有效减少星形胶质细胞的LDH漏出（P〈0．05）。结论星形胶质细胞受到牵拉损伤后,100μmol白藜芦醇能够减少其ATP释放,且能够减少LDH漏出,进而对星形胶质细胞起到保护作用。     

人胎儿中枢神经系统星形胶质细胞形态发育的观察

为观察人胎儿中枢神经系统星形胶质细胞形态发育。用胶质原纤维酸性蛋白抗体进行免疫组织化学染色。结果表明；１．以颈段脊髓，脑干，海马和小脑蚓部于胚胎２５周其ＧＦＡＰ染色强度，细胞密度接近出生时水平。而此时期大脑皮层Ａｓｔ密度约为出生时的四分之一。２．在同一胎龄ＣＮＳ的不同部位，ＧＦＡＰ阳性Ａｓｔ分布不均匀。３．Ａｓｔ不仅在毛细胞血管周围，而且在小血管周围密度大染色深，环绕血管呈辐射状排列。     

星形神经胶质细胞对PC12细胞生长发育的影响

在神经系统的生长发育过程中 ,星形胶质细胞对神经元生长发育的作用是一项重要的研究课题。本文以体外培养的 SD大鼠大脑皮质星形胶质细胞与 PC12神经元按不同细胞数目比例 ( 5 0∶ 1～ 1∶ 1)共同培养 ,并用其制备的条件培养液培养 PC12细胞 ,用快速灵敏的 MTT比色法测定 PC12神经元的细胞活力 ,用光学相差显微镜观察 PC12细胞形态学变化。结果显示 ,星形胶质细胞条件培养液可增强 PC12细胞活力 ( MTT测定的 OD值由 0 .2 5 5± 0 .0 12提高到 0 .5 10± 0 .0 3 6,P<0 .0 0 1,且细胞折光性较对照组强 ) ,却不能促使 PC12神经元突起的生出。将星形胶质细胞与 PC12细胞按 3 0∶ 1～ 1∶ 1的比例共同培养时 ,既可提高 PC12细胞折光性和光晕又可促使其突起的生长 ;如按 5 0∶ 1～ 40∶ 1的比例共同培养时 ,只观察到提高 PC12细胞折光性和光晕 ,而无促使其突起生长发育的作用。本文结果提示 ,PC12神经元细胞活力的提高与星形胶质细胞分泌到条件培养液中的可溶性因子有关 ,而 PC12神经元突起生长发育可能是和与星形胶质细胞的直接接触以及二者的细胞数目比有关。     

星形胶质细胞的可塑性

星形胶质细胞具有可塑性 ,即指其在内外环境变化刺激下 ,在整个生命过程中 ,能改变其自身特性 ,而在表型上呈现出很大程度的可变性。主要表现为细胞大小、形态及数目的变化 ,其中以细胞突起变化最明显。不同发育阶段 ,不同区域的星形胶质细胞可塑性不同。星形胶质细胞可塑性的机制 ,目前认为主要是递质刺激相应的星形胶质细胞受体来实现的     

罗格列酮对大鼠脑出血急性期小胶质细胞和星形胶质细胞的影响

目的:研究罗格列酮对大鼠脑出血后小胶质细胞、星形胶质细胞的影响。方法:雄性SD大鼠随机分为对照组、大剂量干预组、小剂量干预组和假手术组。采用Ⅳ型胶原酶肝素生理盐水尾状核立体定向注射法建立大鼠脑出血模型,大剂量干预组给予罗格列酮2 mg·kg~(-1)·d~(-1)灌胃,小剂量干预组给予罗格列酮0.2 mg·kg~(-1)·d~(-1)灌胃,连续7 d。在术前和术后每日进行1次Longa神经功能缺损评分和尾部微量血糖测量,在术后第2天和第7天采用免疫组织化学检测脑小胶质细胞和星形胶质细胞。结果:大剂量干预组在术后第4天到第7天,小剂量干预组在术后第5天到第7天的Longa神经功能缺损评分低于对照组;大剂量干预组在术后第4天到第7天,小剂量干预组在术后第6天和第7天的微量血糖低于对照组;大剂量干预组术后第2天和第7天血肿周边活化的小胶质细胞较对照组增加,小剂量干预组术后第7天血肿周边活化的小胶质细胞较对照组增加;大剂量干预组和小剂量干预组术后第7天星形胶质细胞较对照组明显增加。结论:罗格列酮可以部分改善大鼠脑出血急性期神经功能,这可能与调节小胶质细胞和星形胶质细胞激活和功能有关。     

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。     

布洛芬对戊四氮点燃癫痫大鼠星形胶质细胞的影响

目的:探讨不同剂量布洛芬对戊四氮(PTZ)点燃癫痫大鼠的影响及其作用机制。方法:雄性SD大鼠60只,随机分为对照组、PTZ组和PTZ+布洛芬组(按布洛芬剂量分为4组),分别对其进行干预,观察记录各组大鼠行为学及脑电图变化,同时观测布洛芬的不良反应,采用免疫荧光染色及Western Blot检测GFAP的表达情况。结果:PTZ组与对照组相比,痫样发作和星形胶质细胞增生明显(P 0. 05); PTZ+布洛芬各组痫样发作和星形胶质细胞增生情况较PTZ组降低,且剂量越高抑制作用越明显(P 0. 05),但不良反应的发生也越多。结论:布洛芬可通过抑制星形胶质细胞增生影响癫痫发作,且剂量越高抑制作用越强,但其不良反应也随剂量的增加而增加。     

Effects of different concentrations of oxygen-ozone on rats' astrocytes in vitro

Although the widespread use of the oxygen-ozone in pain management, there is currently no consensus on its mechanisms of action and nearly no report for its action on nervous cells. Accordingly, the present study was designed to assess the effects of oxygen-ozone on astrocytes. Astrocytes were cultured in vitro through methods of trypsinization, different-speed cultivation and passaging to purify, then seeded into 24 well plates and divided to one of four groups (n=7) to receive the following treatments: respectively added 400 microl complete medium (CM) after effects of 20 microg/ml oxygen-ozone (Group O-20), 40 microg/ml oxygen-ozone (Group O-40), 60 microg/ml oxygen-ozone (Group O-60); without intervention (Group C). After incubation of 2 h or 4 h, cell morphology was observed and endocellular superoxide dismutase (SOD), endocellular malondialdehyde (MDA), lactate dehydrogenase (LDH) leaking ratio, and dead cells' percentage were detected. The results showed cell damage in Group O-60. As compared with Group C, endocellular SOD increased in all groups, MDA at 2 h increased in Groups O-40 and O-60 and MDA at 4 h decreased in Groups O-20 and O-40; LDH leaking ratio at 2 h in Group O-20 and those at 2 and 4 h in Group O-40 decreased, while LDH leaking ratio at 4 h increased and dead cells' percentage in Group O-60 increased. We conclude that in short time (2 and 4 h), oxygen-ozone of 60 microg/ml showed a damaging role on astrocytes in vitro, while oxygen-ozone of 20 and 40 microg/ml did not show damaging role obviously.     

组胺对星形胶质细胞Egr-1表达的调节作用

 目的: 探讨组胺对星形胶质细胞早期反应生长因子-1(Egr-1)表达是否具有调节作用。方法: 将野生型(WT)和组氨酸脱羧酶敲除(HDC-KO)小鼠及组胺处理的HDC-KO小鼠取脑,并提取皮层组织总RNA。将原代培养的大鼠皮层星形胶质细胞分别给予不同浓度的组胺(10^-8、10^-7、10^-6、10^-5或10^-4 mol/L)处理15、30、60、120或240 min。组胺H₁、H₂受体拮抗剂分别于组胺给药前15 min加入。组胺处理完毕后,提取细胞总RNA或蛋白。利用real-time PCR和Western blot测定Egr-1的表达。结果: 与WT小鼠相比,HDC-KO小鼠大脑皮层Egr-1的mRNA表达量显著降低,而外源性给予组胺则能促进其Egr-1的mRNA表达。在培养的星形胶质细胞上,组胺可促进Egr-1的mRNA表达,其中10^-5 mol/L的组胺作用最强,而组胺(10^-5 mol/L)处理30 min时Egr-1的mRNA表达量达到峰值,相应的Egr-1蛋白表达于60 min时显著增高,该作用可被组胺H₁受体拮抗剂而非H₂受体拮抗剂显著抑制。结论: 组胺对大脑皮层组织及培养的星形胶质细胞Egr-1表达具有上调作用,该作用与激动组胺H₁受体有关。     

孕酮对小鼠认知能力及星形胶质细胞表达的影响

目的研究孕酮对成年雌性去卵巢小鼠认知能力的影响,及其与星形胶质细胞GFAP免疫阳性细胞表达是否存在关联性。方法 60只雌性昆明小鼠随机分为5组,除假手术对照组(SHAM组)外,其余各组小鼠行双侧卵巢切除术。术后对各组小鼠分别腹腔注射不同剂量孕酮或生理盐水。用Y-型电迷宫测试系统测定小鼠的认知功能变化,免疫组化法测定星形胶质细胞(astrocytes,AC)标志物胶质纤维酸性蛋白(GFAP)免疫阳性细胞的表达和变化。结果小鼠认知功能测定中,去卵巢对照组(OVX组)小鼠与SHAM组小鼠相比,在第2、3时段正确反应次数显著降低(P<0.05),高孕酮剂量组(HP组)小鼠与OVX组相比,在第3时段正确反应次数显著增高(P<0.05);GFAP表达测定中,OVX组与SHAM组小鼠相比,GFAP阳性细胞AOD和阳性细胞面积表达水平增加(P<0.05),孕酮中剂量组(MP组)和HP组与OVX组小鼠相比,GFAP阳性细胞AOD和阳性细胞面积表达水平降低(P<0.05)。结论雌、孕激素的缺乏会引起成年雌性小鼠认知障碍,孕酮的长期补充治疗可以改善小鼠认知能力,其作用机制与星形胶质细胞的变化相关。     

The effect of tetanus toxin on in vitro synaptogenesis

Cultures of spinal cord neurons and cocultures of rat embryo neurons and muscle cells have been studied in the presence of tetanus toxin (TT) at a concentration of 40 micrograms/ml of medium. TT strongly stimulated neurite outgrowth, notably branching from the cell bodies. In addition it induced a marked, overall increase in acetylcholine receptor (AChR), but inhibited focalisation of AChR and acetylcholinesterase (AChE) at the synaptic sites. TT seems to act on neurite emergence, on the neuronal factor(s) controlling AChE and AChR concentrations, and on the factor(s) modulating degradation and/or synthesis of AChR.     

一氧化氮对星形胶质细胞轴突生长因子-1表达及迁移的影响

目的 探讨一氧化氮(NO)对星形胶质细胞中轴突生长因子-1(netri-1)的表达变化以及对细胞迁移的影响。方法 采用硝普钠（SNP）作为NO供体处理星形胶质细胞,通过振荡培养和差速贴壁法分离纯化新生SD大鼠星形胶质细胞,接种至培养板,分为实验组和对照组,每组6个样本,实验组用50μmol/L SNP处理星形胶质细胞,通过划痕法观察细胞的迁移,并采用Western blotting 和免疫细胞化学方法分别检测处理前后的星形胶质细胞中netrin-1蛋白的表达变化。 结果 SNP处理后,实验组的星形胶质细胞与对照组相比,划痕区细胞明显增多,星形胶质细胞netrin-1表达随着时间的推移出现先升高后降低趋势,于48 h达到峰值 (P<0.01)。 结论 SNP使星形胶质细胞netrin-1表达水平发生变化和影响星形胶质细胞迁移,提示netrin-1可能通过NO的调控而影响星形胶质细胞迁移。     

Effects of polyunsaturated fatty acids and hormones on synaptogenesis in serum-free medium cultures of mouse fetal hypothalamic cells

The effects of soluble factors on synaptogenesis by mouse fetal hypothalamic cells cultured in chemically defined conditions have been examined using transmission electron microscopy. Hypothalami taken on the 16th day of gestation were mechanically dissociated and cells were seeded in a minimum serum-free medium supplemented or not with the following components: triiodothyronine, corticosterone and a mixture of polyunsaturated fatty acids (arachidonic acid plus docosahexaenoic acid bound to defatted bovine serum albumin). In the minimum serum free medium synapses were found after 10 days in culture. However, the development of synaptic vesicles was very limited, whereas that of the presynaptic and postsynaptic densities was apparently normal. Supplementation of the minimum serum-free medium with triiodothyronine, corticosterone and polyunsaturated fatty acids added simultaneously, permitted a full development of synapses as attested to by the increase in number and the regular shape and diameter of synaptic vesicles as well as by the complexity and diversity of synapse configurations. Among those three factors, polyunsaturated fatty acids clearly played a key role. The ability of synapses formed in culture to respond to potassium evoked depolarization was examined on cultures grown for 12 days in the simultaneous presence of the three above mentioned supplements. Exposure for 3 min to 60 mM potassium chloride induced in synaptic boutons vesicular depletion, apposition of vesicle clusters onto the presynaptic grid, appearance of a rich filamentous network and of some coated vesicles. Return to 3mM potassium chloride induced in 3 min a massive restoration of the population of vesicles which slightly differed from synaptic vesicles in control cultures. These results show that: (1) the formation of synaptic vesicles in this system is regulated by soluble factors among which polyunsaturated fatty acids play a major role, and (2) synapses formed de novo in chemically defined conditions of culture display the same ability to respond to and to recover from potassium evoked depolarization as adult axon terminals. Thus, they offer a suitable model for analysis of the mechanisms involved in membrane traffic in central neurons.     

Effects of neonatal intraocular colchicine on synaptogenesis and on the retention of the ipsilateral retinofugal projection within the superior colliculus

Summary A normally transient ipsilateral retinofugal projection exists in the rat but is retained following eye removal because of the loss of competitive interaction between crossed and uncrossed fibers. To further explore this phenomenon, colchicine (10^–3M) was injected into the right eye of newborn albino rats to partially suppress axonal transport in optic fibers, alter the developmental time course of retinofugal synaptic terminals and determine if this would in turn extend the period of survival of the ipsilateral projection. Measurements of the number of fibers in the nerve were also made to insure that colchicine was not lethal to the retinofugal projection. Projections into the superior colliculus were demonstrated by anterograde movement of HRP from the left eye. TMB histochemistry revealed dense labeling of the contralateral retino-recipient layers at 5 dpn in untreated or saline-injected controls. The ipsilateral projection was seen as a lighter band of activity across the colliculus which was most concentrated in the antero-medial quadrant. This pathway was transient and degenerated by 10 dpn, except for a few antero-medial fibers. Animals treated with colchicine demonstrated a retention of this pathway through 20 dpn. A concomitant quantitative analysis of synaptic development within the superior colliculus revealed populations of boutons with round (R) and flattened (F) vesicles, as well as multiple junctional (MJ) and serial (S) complexes, most of which were specialized R boutons. The various synaptic categories displayed specific ratios unique to the different stages of maturation. Intraocular colchicine reduced the ratio of R, MJ and S boutons to F terminals between 5–15 dpn (P < 0.01). By 20 dpn, the proportions of MJ and S boutons remained depressed but the normal ratio of R to F boutons was restored. Areal determinations of each synaptic profile included in the counts revealed a significant reduction in the size of MJ synaptic profiles examined in colchicine-treated animals and this may have been reflected in the slight loss of tectal volume (6–9%). Removal of the left eye and assessment of degenerating boutons showed that the expanded ipsilateral projection was not sufficiently dense to produce such a restoration. It thus appears that colchicine delayed the growth of the R population, but the effect was reversible and this category of boutons continued to develop, albeit on a later time course. Continued depression of MJ and S boutons suggests that suppression of the rate and quantity of axonally-transported substances retards the final stages of tectal synaptic differentiation, reduces their competitive advantage and allows the retention of the ipsilateral optic projection.     

Effects of neonatal flutamide treatment on hippocampal neurogenesis and synaptogenesis correlate with depression-like behaviors in preadolescent male rats

The prevalence of major depressive disorder (MDD) in adult men is roughly half that of women. Clinical evidence supports a protective effect of androgens against depressive disorders in men. The developing brain is subject to androgen exposure but a potential role for this in depression during adulthood has not been considered. In order to explore this question we treated newborn male rat pups with the androgen receptor antagonist flutamide to block endogenous androgen action and then conducted behavioral tests prior to puberty. Depression-like behaviors were assessed with the Forced Swim Test (FST) and the Sucrose Preference Test (SPT), and anxiety-like behaviors were assessed with the Open Field Test (OFT) and the Novelty-Suppressed Feeding Test (NSFT). Compared to the vehicle-treated controls, neonatal-flutamide treatment caused a significant increase in depression-like behaviors in preadolescent male rats but did not cause any significant difference in anxiety-like behaviors. In separate experiments, male pups with and without flutamide treatment were injected with 5-bromo-2′-deoxyuridine-5′-monophosphate (BrdU) from postnatal day (PND) 1 to 4 to label newly produced cells or the hippocampi were Golgi-Cox imbedded and pyramidal neurons visualized. Three lines of evidence indicate neonatal flutamide treatment inhibits hippocampal neurogenesis and neuronal dendritic spine formation in preadolescent male rats. Compared to vehicle controls, flutamide treatment significantly decreased (1) the number of microtubal associated protein-2+ (MAP-2) neurons in the CA1 region, (2) the number of MAP-2+ neurons in the dentate gyrus (DG) region of the hippocampus, and (3) the density of dendritic spines of pyramidal neurons in the CA1 region. However, there was no effect of flutamide treatment on the number of glial fibrillary acidic protein (GFAP)+ or GFAP+/BrdU+ cells in the hippocampus. This study suggests that the organizational effect of androgen-induced hippocampal neurogenesis is antidepressant.