Nogo-A蛋白的表达与少突胶质细胞肿瘤恶性程度呈负相关

目的探讨Nogo—A蛋白在少突胶质细胞肿瘤中的表达水平与该肿瘤恶性程度之间的关系。方法选取来自临床上经病理检查确诊为少突胶质细胞肿瘤的组织标本,其中少突胶质细胞瘤16例,间变型少突胶质细胞瘤10例。免疫组织化学染色检测Nogo—A的表达,并与同视野下瘤细胞的核分裂与核异型性比例作相关分析;另外,把病理标本按照分级进行蛋白印迹试验。结果免疫组织化学结果显示,Nogo—A免疫阳性染色的光密度值与肿瘤细胞核分裂、核异型比例呈明显的负相关,对蛋白印迹试验结果进行光密度分析也发现少突胶质细胞瘤中的Nogo-A蛋白条带灰度值明显高于间变型少突胶质细胞瘤中的灰度值。结论Nogo-A蛋白在少突胶质细胞肿瘤中的表达水平与该肿瘤恶性程度呈负相关。     

不同级别少突胶质细胞肿瘤p16INK4a表达及预后关系

目的 研究p16INK4a在少突胶质细胞肿瘤中的表达,并探讨其与肿瘤恶性程度及预后关系.方法 回顾性分析42例经病理证实的少突胶质细胞肿瘤患者的病史资料,采用EnVision免疫组化法检测p16INK4a表达水平,并通过电话、门诊和书信等方式随访患者生存期.结果 p16INK4a总阳性表达率为66.7%(28/42),OG(WHOII)组和AOG(WHOIII)组分别为77.4%(24/31)和36.4%(4/11)(P＜9.05).42例患者中,6例失访,失访率为14.3%,中位生存期p16INK4a(-),( )和( )组分别为2.3年、4.9年和8.9年(P＜0.05).Log-rank检验显示随p16INK4a的表达强度的降低,患者生存时间缩短.结论 p16INK4a表达强度是少突胶质细胞肿瘤预后较好的生物学指标之一.     

新生SD大鼠少突胶质细胞前体细胞的培养与分化

目的 体外培养高纯度的少突胶质前体细胞（oligodendrocyte progenitor cells,OPCs）以及分化成熟的少突胶质细胞（Oligodendrocytes,OLs）.方法新生1 -2 d Sprague-Dawley（SD）大鼠的大脑皮层胶质细胞混合培养9d后采用恒温摇床振荡分离与差异贴壁方法并结合条件培养基纯化培养细胞.光学显微镜观察细胞形态;纯化培养3 d后免疫荧光染色鉴定细胞类型.结果 获得高纯度的少突胶质前体细胞以及成熟的少突胶质细胞,少突胶质前体细胞免疫荧光NG2＋A2B5双标阳性,成熟少突胶质细胞免疫荧光MBP染色阳性.结论 采用恒温摇床振荡分离与差异贴壁法并结合条件培养基可以得到高纯度的少突胶质前体细胞以及成熟少突胶质细胞.     

精神分裂症与少突胶质细胞相关研究进展

本文综述了少突胶质细胞相关基因SOX10,NRG1,Nogo等对精神分裂症的影响,影像学动物学发现了少突胶质细胞与精神分裂症的关系,提出了少突胶质细胞是精神分裂症发病的关键之一,并可作为治疗靶点。     

少突胶质细胞表观遗传学调控机制的研究进展

机体发育中少突胶质细胞谱系定型、特化、增殖、迁移、分化、成熟、髓鞘形成以及脱髓鞘疾病髓鞘重塑过程受到内外多因素的调控。近年来,表观遗传调控机制研究越来越多,包括DNA甲基化、组蛋白修饰、非编码RNA、染色质重塑等。研究表观遗传调控为髓鞘形成障碍或者髓鞘破坏性疾病,如多发性硬化、早产儿脑室周围白质损伤及脑脊髓炎等提供了潜在的治疗新靶点。本文现围绕少突胶质细胞表观遗传学调控机制的研究进展综述如下。     

少突胶质细胞的钙信号

钙是细胞内重要的第二信使,参与机体内多种生理过程,其胞内的钙信号传递依赖于胞内外的钙离子(Ca2+)浓度差,表现为胞质内钙的变化.Ca2+进入细胞内与钙的受体如钙调素(calmodulin,CaM)结合后发挥系列效应.以往认为Ca2+仅在兴奋性细胞中起传递信号作用,但近年来随着研究的深入,发现无论是兴奋性还是非兴奋性细胞,钙都作为第二信使参与信号转导及基因的表达调控.少突胶质细胞是中枢神经系统髓鞘形成细胞,被认为是中枢神经系统中一种非兴奋性细胞,其对于细胞外的刺激可表现为胞内钙浓度的变化从而调控细胞活动.     

少突胶质细胞与再髓鞘化

脱髓鞘疾病是目前世界范围内的一种常见的神经系统疾病,而多发性硬化中的脱髓鞘变化是其中研究比较深入的一种。与多发性硬化患者临床缓解——复发病程相对应的脱髓鞘与再髓鞘化给治疗提供了一些策略,促进脱髓鞘疾病患者的再髓鞘化。鉴于在体内存在少突胶质细胞的前体细胞池,这就对我们提出了如何诱导体内的前体细胞向少突胶质细胞的分化的问题。首先要求我们了解参与再髓鞘化过程的细胞及分子。本文对再髓鞘化过程中的重要的细胞——少突胶质细胞的生物学特性及在髓鞘化过程中的作用作一概述。     

小胶质细胞和少突胶质细胞前体的培养和鉴定

目的 探讨新生大鼠脑组织小胶质细胞(MG)和少突胶质细胞(OL)前体的分离和体外培养方法 . 方法 取新生2 d SD大鼠脑组织,体外原代培养混合胶质细胞7 d后,分别采用"改良振荡伴差速贴壁"法和"营养缺失伴振荡"法纯化培养MG和OL前体,并分别应用免疫荧光染色异凝集素-B4(IB4)和OL前体标记物(O4)进行鉴定.结果 混合胶质细胞培养7 d后呈明显三层增长,其中MG位于上层,星型胶质细胞位于底层,两者之间为2型少突星型(O2A)祖细胞.纯化培养后OL前体胞体呈小圆形,有双极或三极突起,MG则以阿米巴形、圆形居多,或边缘呈毛刺状.免疫荧光染色IB4显示绿色荧光,MG纯度达到90%以上.免疫荧光染色O4显示棕黄色荧光,OL前体纯度达到95%以上. 结论 采用"改良振荡伴差速贴壁"法以及"营养缺失伴振荡"法分别成功获取大量纯度高、活力好的MG和OL前体.     

少突胶质细胞异常与精神分裂症关系的研究进展

精神分裂症（schizophrenia）是一种严重的精神疾病,以思维,情感与行为障碍为主要表现,近年来研究发现其病因与发病机制与少突神经胶质细胞异常及髓鞘形成障碍有关。     

少突胶质细胞在癫痫中的研究进展

癫痫是大脑神经元反复超同步异常放电引起的大脑功能障碍.国内外的研究发现,癫痫发作后存在胶质细胞增生、神经元变性、坏死及中枢神经髓鞘脱失等病理变化,而少突胶质细胞(oligodendrocytes,OLs)在以上病理过程中发挥着重要作用[1].Gary等[2]对混合大脑皮质培养的细胞进行双相脉冲电刺激后发现,轴突接触、信号传递及神经元的活性能促使OLs存活,这说明神经元的活性能成为OLs生存的条件之一.研究证明OLs的主要功能包括:(1)包绕神经纤维的轴突而形成髓鞘[3];(2)分泌神经营养因子,促进神经元和胶质细胞的存活及功能发挥[4];(3)表达抑制性蛋白,阻止神经纤维的过度生长[5].近年来,关于OLs在癫痫发病中的作用逐渐受到关注,研究发现OLs可能与癫痫发病存在一定相关性.本文复习了国内外关于OLs与癫痫发病研究的相关文献,以OLs的生物学功能在癫痫发病中发挥的作用为重点进行综述,以期为相关领域的研究者提供参考.     

Nogo-A and Nogo-A receptor expression in periventricular white matter of experimental autoimmune encephalomyelitis rats

BACKGROUND:Previous studies have focused on the correlation between Nogo-A expression and multiple sclerosis or between Nogo-A receptor (NgR) expression and multiple sclerosis in the central nervous system. Expression patterns of Nogo-A and NgR remain poorly understood in rat models of experimental autoimmune encephalomyelitis (EAE).OBJECTIVE:To observe dynamic changes in Nogo-A and NgR protein expression, and to verify the correlation between Nogo-A and NgR protein, as well as expression patterns at various time points, in periventricular tissue of EAE rats.DESIGN, TIME AND SETrlNG:A neuroimmunological, randomized, controlled experiment was performed at the Clinical Institute of Hunan People's Hospital of China from September to November 2008.MATERIALS:Immunohistochemistry (streptavidin-biotin-peroxidase complex method) kit was purchased from Boster, China.METHODS:A total of 60 female, Wistar rats, aged 6-8 weeks, ware randomly assigned to EAE and control groups (n = 30, respectively). Guinea pig spinal cord homogenate, self-made complete Freund's adjuvant (0.2 mL/100 g), and pertussis vaccine (0.2 mL) were subcutaneously injected into the hindlimb foot pad of rats from the EAE group to create rat models of EAE. Complete Freund's adjuvant (0.2 mL) was infused into rats from the control group.MAIN OUTCOME MEASURES:Nogo-A and NgR protein expression was determined in periventricular white matter using immunohistochemical methods. Neurological scores ware determined in all rats.RESULTS:Rats from the EAE group developed acute-onset EAE following immunization. The pathogenetic symptoms reached a peak on day 15, and neurological scores ware also greatest at this time point. Neurological scores decreased with recovery of the illness. Nogo-A was shown to be expressed in neuronal cells and oligodendrocytes, and expression increased 11 days after immunization (P < 0.01), decreased by day 13 (P < 0.01), and then increased again by day 15. Nogo-A expression remained greater in the EAE group compared with the control group at day 30 (P < 0.01). In the EAE group, NgR protein was primarily expressed on the surface of neuronal bodies and axons. NgR expression increased 13-18 days after immunization (P < 0.01 or P < 0.05).CONCLUSION:Nogo-A and NgR protein expression altered with disease course in periventdcular white matter of EAE rats. Results suggested that Nogo-A and NgR were involved in EAE occurrence.     

大鼠脊髓损伤后Nogo-A表达变化的免疫组织化学研究

目的观察大鼠脊髓损伤后不同时间点Nogo—A蛋白在脊髓的表达变化。方法大鼠分脊髓损伤组、假手术组和正常对照组。损伤动物存活1d、3d、7d后，分别进行Nogo—A抗体的免疫组织化学染色。结果损伤部位的灰质神经元和白质少突胶质细胞均呈明显的Nogo—A免疫阳性反应，随着损伤后存活时间的延长，两者的阳性反应细胞相对染色强度及数量均逐渐下降。结论脊髓损伤后，Nogo—A在灰质神经元有表达，其表达相对强度和表达细胞数量先明显增加，随后逐渐减少，与少突胶质细胞的表达变化相似。     

实验性自身免疫性脑脊髓炎大鼠脑组织Nogo-A和NgR的变化

背景：Nogo-A蛋白是一种中枢神经系统髓鞘相关轴突再生抑制因子,与其受体作用可抑制轴突再生。 目的：观察实验性自身免疫性脑脊髓炎（Experimental Autoimmune Encephalomyelitis,EAE）大鼠侧脑室周围Nogo-A和NgR蛋白的动态变化,探讨Nogo-A和NgR蛋白在EAE发生发展中的可能作用机制。 设计、单位、时间：随机对照动物研究。试验于2008年9月至11月在湖南省人民医院临床研究所进行。 材料：6~8周龄清洁级雌性Wistar大鼠60只,体重（180±10）g,由湖南农业大学动物科技学院实验动物养殖场提供。 方法：60只大鼠随机分为EAE组和对照组各30只,各组再分为6个亚组,每组5只大鼠,分别于免疫后11天、13天、15天、18天、24天、30天处死各亚组大鼠取脑。采用免疫组化方法测定2组大鼠侧脑室周围白质Nogo-A和NgR蛋白在不同时间点表达情况。 主要观察指标：通过免疫组化后阳性细胞数计数观察侧脑室周围Nogo-A和NgR表达水平。 结果：EAE组在免疫第11天Nogo-A蛋白表达升高,第13天下降,后又升高,第30天仍高于对照组;EAE组NgR蛋白在第13、15、18表达升高。 结论：Nogo-A和NgR蛋白可能在EAE的发生发展中起重要作用     

Apotransferrin and the cytoskeleton of oligodendroglial cells

Apotransferrin (aTf), has been shown to accelerate the differentiation of oligodendroglial cells (OLGcs) in primary cultures and to increase the expression of different components of the myelin cytoskeleton (CSK). We examined the incorporation and distribution of human aTf (aTfh) exogenously added to OLGcs cultures and its effects on the CSK of the OLGcs. When OLGcs treated with aTfh were extracted with a CSK-stabilizing buffer containing detergent, aTfh was found in the soluble fraction. In vitro experiments showed that purified tubulin was not altered by the addition of aTfh. In OLGc primary cultures treated with aTfh, this glycoprotein showed a punctate distribution pattern along the OLGc processes. Treatment of the cultures with colchicine, cytochalasin, or taxol induced a displacement of the immunoreactivity of aTfh toward the OLGc soma. Analysis of the effects of aTfh on the cell distribution of tyrosinated and detyrosinated tubulin and STOP (stable tubule only polypeptide), showed that aTfh added to OLGc cultures promoted changes suggesting a stabilizing effect on the microtubules (MT) at the tip of the processes. Kinesin and dynein were found to colocalize with the aTfh, indicating that these motors participate in the transport of the added glycoprotein. Moreover, after treatment with aTfh, clathrin immunoreactivity was displaced from the OLGc body toward the cell processes. These results indicate that although aTfh added to OLGcs does not interact directly with CSK components, it seems to be transported in clathrin coated vesicles from the cell body to the tips of the OLGc processes where it promotes their stabilization. This mechanism may be of importance in the increased formation of the myelin membrane induced by aTf.     

Nogo-A/NgR通路参与缺血预处理对局灶性脑缺血的神经保护作用

目的研究Nogo-A/NgR通路参与缺血预处理(IPC)对局灶性脑缺血的神经保护作用。方法雄性成年SD大鼠随机分为:对照组(C)、缺血预处理组(IPC)、Tat-NEP1-40组和Tat-β-Gal组。大脑中动脉栓塞(MCAO)10min作为IPC,IPC组在IPC后72h建立MCAO致局灶性脑缺血模型。再灌注24h后,对所有动物行神经功能缺损评分(NDS),并处死大鼠取脑,应用2%TTC染色测定梗死容积和免疫组化研究Nogo-A和NgR表达变化。结果与C组比较,IPC组显著改善局灶性脑缺血再灌注后24h大鼠的NDS[2(1.5~3)和1(0~2)](P<0.01)、减少脑梗死容积[(309.65±54.61)mm3和(65.09±26.06)mm3](P<0.01),NgR拮抗剂NEP1-40可部分逆转IPC的神经保护作用(P<0.01),而其溶剂β-Gal对IPC的神经保护作用无明显影响。免疫组化显示Nogo-A和NgR阳性细胞主要位于MCAO后导致的缺血区域,缺血后24h大鼠缺血区域Nogo-A和NgR表达明显增强,IPC可抑制缺血引起的Nogo-A和NgR表达增强。结论Nogo-A/NgR通路可能参与IPC诱导的脑缺血耐受,保护脑缺血性损伤。     

Nogo-A和NgR在老年大鼠脑组织中的表达分布

目的研究Nogo—A和NgR在老年大鼠脑内的表达阳性分布。方法免疫组织化学方法（ABC法）。结果Nogo-A和NgR在老年大鼠脑内的神经元和神经纤维有广泛的表达且阳性反应的强度不同。结论Nogo-A和NgR在老年大鼠脑内广泛表达可能在衰老中发挥作用。     

大鼠脑挫伤后Nogo-A mRNA表达水平变化的实验研究

目的观察大鼠脑挫伤后Nogo-AmRNA在神经组织表达量的变化。方法取35只SD大鼠,随机分为7组,每组各5只。1组设为正常对照组,其余6组分别在脑挫伤(自由落体打击脑损伤)后12、24h及3、9、15、21d处死,取脑组织提取RNA,采用半定量RT-PCR法,检测正常及各损伤组Nogo-AmRNA的相对水平。结果脑组织中Nogo-AmRNA表达量在损伤后12h开始出现明显升高(0.1373±0.0009),24h表达稍有下降(0.1067±0.0008),3d后再次上升(0.1220±0.0010),至第9天达到高峰(0.1762±0.0007)并维持于较高水平,至伤后15d(0.1397±0.0005)缓慢下降,伤后21d(0.0129±0.0002)恢复至伤前水平。结论中枢神经损伤后,Nogo-A在抑制神经再生过程中可能发挥着重要作用。     

Expression of Nogo-A mRNA after injury of the rat central nervous system

BACKGROUND： Nogo protein has been identified as an inhibitor of axonal growth, which was highly expressed in central nervous system; however, there are only a few studies on changes of Nogo-A expression following central nervous system injury. OBJECTIVE： To investigate the dynamic expression of Nogo-A mRNA after rat central nervous system injury. DESIGN： Randomized controlled animal study. MATERIALS： Thirty-five rats were randomly divided into two groups, normal animal group （n = 5） and model group （n = 30）. The model group was then divided into six subgroups at six time points： 12, 24 hours and 3, 9, 15, and 21 days post-injury, with five rats in each subgroup. METHODS： The left parietal lobe of rats was contused by free-fall strike, and total RNA was extracted from the entire brain tissue. Semi-quantitative RT-PCR was used to detect Nogo-A mRNA expression, and the ratio between expression of the target gene and glyceraldehyde phosphate dehydrogenase was used to determine the relative expression level. MAIN OUTCOME MEASURES： To determine whether Nogo-A mRNA expression was higher than usual following brain injury. RESULTS： The level of Nogo-A mRNA started to increase 12 hours after injury （P 〈 0.05） and decreased slightly by 24 hours post-injury. Expression increased again on day 3 and reached a peak on day 9. Nogo-A mRNA expression started to decrease on day 15, and then decreased to normal levels at days 21 （P 〉 0.05）. CONCLUSION： After injury of the central nervous system, Nogo-A may play a pivotal role in obstructing regeneration of the nerve.     

Nogo-A在神经细胞分子调控中的研究现状

视神经是中枢神经系统的一部分,其损伤后再生能力有限.眼外伤等因素引起视神经损伤,往往给伤者带来不可逆转的视功能损害,导致患者视力严重受损.因此,探讨中枢神经再生困难的原因对视神经再生以及视功能的恢复有重要借鉴意义.成年哺乳动物中枢神经损伤后再生困难,研究认为这可能和中枢神经髓磷脂中某种蛋白的抑制作用有关.