星形胶质细胞对脑缺血后神经元的保护作用

神经元和神经胶质细胞共同构成中枢神经系统。而其中星形胶质细胞(astrocytes,AS)在数量上占有绝对优势,其数量是神经元的10～50倍,约占脑体积的一半。AS长期以来被认为是脑组织中简单的堆积物,发     

反应性星形胶质细胞对脑缺血神经元的保护

近年来研究发现星形胶质细胞在脑缺血后异常活跃。它可通过分泌生长因子、细胞因子、识别分子等修复损伤的神经元,促进轴突再生及诱导再生神经元的迁移。起到恢复神经系统正常功能的作用。现综述如下。1 星形胶质细胞损伤对神经元的影响近10年研究表明神经胶质细胞在神经系统发育、突触传递、神经组织的修复与再生、神经免疫及多种神经疾病的病理机制中都起着十分重要的作用。用选择性胶质毒素Fluorocitrate(FC)注射入无损伤的鼠脑,造成早期胶质细胞功能紊乱,而产生类似缺血半影区的改变,而且发现在缺乏正常胶质细胞时神经元对扩散性…     

siRNA下调星形胶质细胞中PTEN表达对缺氧复氧诱导细胞凋亡影响

目的研究siRNA下调星形胶质细胞中第10号染色体同源缺失性磷酸酶-张力蛋白(PTEN)表达对缺氧复氧诱导的细胞凋亡影响。方法分离培养乳鼠星形胶质细胞,用携带PTEN siRNA的慢病毒载体感染星形胶质细胞,经缺氧复氧处理后,用Real time PCR和Western blot检测细胞中PTEN表达变化。MTT测定细胞增殖活力,二硝基苯肼比色法检测乳酸脱氢酶(LDH)漏出率,流式细胞术测定周期和凋亡变化,Western blot检测细胞中细胞周期依赖性蛋白激酶4(Cdk4)、p21蛋白水平和胞质中细胞色素C(Cytochrome C)蛋白水平,JC-1法测定线粒体膜电位。结果携带PTEN siRNA的慢病毒载体感染后的星形胶质细胞中PTEN表达水平降低。缺氧复氧处理后的星形胶质细胞活力降低,细胞LDH漏出率升高,细胞凋亡率升高,细胞G1期比例升高,Cdk4蛋白水平降低,p21蛋白水平升高,胞质中Cytochrome C蛋白增多,线粒体膜电位降低。敲低PTEN可以提高缺氧复氧条件下星形胶质细胞活力,降低细胞LDH漏出率,减少G1期细胞比例,降低细胞凋亡率,促进细胞表达Cdk4蛋白,减少细胞表达p21,减少胞质中Cytochrome C蛋白,提高线粒体膜电位。结论敲低PTEN可以减少缺氧复氧诱导的星形胶质细胞凋亡,作用机制与线粒体凋亡途径有关。     

双他克林对原代培养小鼠星形胶质细胞缺氧缺糖损伤的保护作用

目的 :研究一种新的乙酰胆碱酯酶抑制剂双他克林在缺氧、缺糖诱导的细胞坏死和细胞凋亡中的作用。方法 :用缺氧和缺糖来诱导原代培养的小鼠大脑皮层星形胶质细胞损伤 ,通过测定 L DH释放量观察细胞存活率 ;相差显微镜和 Hoechst 33342染色观察细胞和核形态 ,并计数核固缩的细胞数量。结果 :缺氧、缺糖 6 h后约 6 0～ 70 %的细胞发生凋亡 ,使用双他克林 (1- 10 n M)可有效抑制缺氧、缺糖诱导的细胞凋亡 ,从形态学和生化检测两方面均可证实这一结果。结论 :双他克要可保护星形胶质细胞免受缺氧、缺糖性损伤。提示除了 AD外 ,该药还可用于血管性痴呆的治疗     

星形胶质细胞激活与创伤性颅脑损伤研究进展

神经胶质细胞作为中枢神经系统中分布最为广泛的一类细胞,对神经元具有支持、保护、营养、形成髓鞘和修复等多种功能。星形胶质细胞作为神经胶质细胞中的一种,已有大量研究证实其在创伤性脑损伤和神经退行性病变中具有重要作用。文中结合相关文献综述介绍创伤性颅脑损伤后星形胶质细胞激活的病理过程及其中潜在的细胞及分子机制     

缺氧／复氧对星形胶质细胞AQP4表达的影响

目的 探讨缺氧/复氧对于体外培养星形胶质细胞表达AQP4的影响及缺血性脑血管病脑水肿的发病机制.方法 选取新生24 h Wistar大鼠脑组织行星形胶质细胞原代培养并建立缺氧/复氧模型,应用Western blot和免疫细胞化学法检测星形胶质细胞AQP4的表达变化.结果 与对照组比较,缺氧3 h和6 h星形胶质细胞AQP4蛋白表达减少(P<0.01),复氧后6 h和9 h其表达明显增高(P<0.01).结论 AQP4表达变化与细胞损害相关.     

星形胶质细胞对神经回路形成作用研究进展

星形胶质细胞(astrocytes, Ast)是哺乳动物大脑中含量最多的神经胶质细胞,它在维持血脑屏障、调节局部血流量、抗氧化和代谢支持以及神经回路的形成上起着重要的作用。星形胶质细胞可以通过各种分泌信号控制突触的形成、成熟和修剪。近年来,在突触缺陷所引起的一系列神经精神疾病中也可以发现星形胶质细胞的身影,了解星形胶质细胞在神经回路发育和功能的调控,有助于对这一系列健康疾病问题提供新的治疗手段。神经回路的形成主要包括三个过程,首先,轴突和树突之间形成未成熟突触;其二,突触成熟,沉默突触转化为活性突触;其三,敲除和修剪过量及不合格突触。星形胶质细胞可以控制突触形成、成熟和消除的每个阶段以支持神经回路的发生和维护。现将星形胶质细胞对神经回路形成的调节作用研究进展综述如下。     

鱼藤酮对中脑星形胶质细胞的损伤及阿糖胞苷的干预作用

目的 观察鱼藤酮毒性作用及阿糖胞苷(ara-c)干预对体外培养中脑腹侧星形胶质细胞增殖、还原型谷胱甘肽(GSH)含量及胶质细胞源性神经营养因子(GDNF)表达的影响. 方法 体外培养大鼠中脑腹侧星形胶质细胞随机分成9组,分别为对照组,10、20、40及60nmol/L鱼藤酮短时程损伤组(用相应浓度鱼藤酮处理24 h),10及20 nmol/L鱼藤酮长时程损伤组(相应浓度鱼藤酮处理30 d),10及20 nmol/L鱼藤酮长时程损伤+ara-c处理组(相应浓度鱼藤酮处理30 d,500nmol/L ara-c处理6 d).增殖细胞核抗原(PCNA)免疫细胞化学染色观察细胞增殖情况,GSH检测试剂盒检测细胞GSH含量.免疫细胞化学方法 和Western blot检测GDNF的表达情况. 结果短时程损伤各组10和20 nmol/L鱼藤酮作用 24 h未能使细胞GSH含量及GDNF表达最降低,但40和60 nmol/L鱼藤酮作用24 h可使细胞GSH含量降低、GDNF表达减少.长时程损伤组10和20nmol/L鱼藤酮作用30 d后处于增殖状态的星形胶质细胞比例增高,GSH含量未见降低.但GDNF表达量减少:500nmol/L ara-c抑制细胞增殖后,可使GDNF的表达回升至接近对照组水平且GSH含量明显提高. 结论 鱼藤酮可影响中腩腹侧旱形胶质细胞的增殖和功能,恶化多巴胺能神经元的生存微环境;低浓度ara-c可通过抑制旱形胶质细胞的过度增殖,恢复GDNF表达量并明显提高GSH含量,提示ara-c对帕金森病具有潜在的治疗价值.     

鱼藤酮对中脑星形胶质细胞的损伤及阿糖胞苷的干预作用

Objective To observe the toxic effects of rotenone on the proliferation, γ-glutamylcysteinylglycine (GSH) content and the expression level of glial cell line-derived neurotrophic factor (GDNF) of rat rnidbrain astrocytes in vitro and the interventional effect of arabinoeytidine (ara-c). Methods In vitro cultured rat midbrain astrocytes were assigned randomly into 9 groups, including a normal control group, 4 short-term rotenone treatment groups exposed for 24 h to 10, 20, 40 or 60 nmol/L rotenone, 2 long-term rotenone treatment groups exposed for 30 days to 10 or 20 nmol/L rotenone, and 2 ara-c groups with 500 nmol/L ara-c treatment following exposure to 10 or 20 nmol/L rotenone for 6 days. The cell proliferation was assessed by immunocytochemical detection of the expression of proliferating cell nuclear antigen (PCNA). GSH content in the treated cells was measured by GSH detection kit, and the expression of GDNF was detected with immunocytochemistry and Western blot. Results The 24-h exposure to low-level rotenone (10 and 20 nmol/L) did not cause any changes in GSH content or GDNF expression in the cells. But at 40 and 60 nmol/L, rotenone treatment for 24 h significantly decreased the GSH content and GDNF expression. Rotenone exposure for 30 days increased the ratio of proliferating astrocytes and decreased GDNF expression level, but the GSH content remained stable. The application of 500 nmol/L ara-c to suppress the cell proliferation restored the expression level of GDNF to almost the control level and markedly increased GSH content. Conclusion Rotenone affects the proliferation and activity of rat midbrain astrocytes in vitro and deteriorates the microenvironment of dopaminergic neurons. Low-level ara-c can increase the GSH content and GDNF expression levels by suppressing the proliferation of rotenone-exposed astrocytes, suggesting its potential value in the treatment of Parkinson's disease.     

鱼藤酮对中脑星形胶质细胞的损伤及阿糖胞苷的干预作用

Objective To observe the toxic effects of rotenone on the proliferation, γ-glutamylcysteinylglycine (GSH) content and the expression level of glial cell line-derived neurotrophic factor (GDNF) of rat rnidbrain astrocytes in vitro and the interventional effect of arabinoeytidine (ara-c). Methods In vitro cultured rat midbrain astrocytes were assigned randomly into 9 groups, including a normal control group, 4 short-term rotenone treatment groups exposed for 24 h to 10, 20, 40 or 60 nmol/L rotenone, 2 long-term rotenone treatment groups exposed for 30 days to 10 or 20 nmol/L rotenone, and 2 ara-c groups with 500 nmol/L ara-c treatment following exposure to 10 or 20 nmol/L rotenone for 6 days. The cell proliferation was assessed by immunocytochemical detection of the expression of proliferating cell nuclear antigen (PCNA). GSH content in the treated cells was measured by GSH detection kit, and the expression of GDNF was detected with immunocytochemistry and Western blot. Results The 24-h exposure to low-level rotenone (10 and 20 nmol/L) did not cause any changes in GSH content or GDNF expression in the cells. But at 40 and 60 nmol/L, rotenone treatment for 24 h significantly decreased the GSH content and GDNF expression. Rotenone exposure for 30 days increased the ratio of proliferating astrocytes and decreased GDNF expression level, but the GSH content remained stable. The application of 500 nmol/L ara-c to suppress the cell proliferation restored the expression level of GDNF to almost the control level and markedly increased GSH content. Conclusion Rotenone affects the proliferation and activity of rat midbrain astrocytes in vitro and deteriorates the microenvironment of dopaminergic neurons. Low-level ara-c can increase the GSH content and GDNF expression levels by suppressing the proliferation of rotenone-exposed astrocytes, suggesting its potential value in the treatment of Parkinson's disease.     

Ischemic preconditioning is mediated by erythropoietin through PI-3 kinase signaling in an animal model of transient ischemic attack

Ischemic preconditioning (IP) protects the brain from subsequent, prolonged, and lethal ischemia in experimental studies. Erythropoietin (EPO) participates in the brain's intrinsic response to injury and may play a role in preconditioning. By using a middle cerebral artery occlusion (MCAo) model of transient ischemic attack (TIA), we sought to determine whether EPO is required for IP in the protective response against focal ischemic stroke. Rats underwent three 10-min MCA occlusions or sham surgery. Three days later, animals underwent 2 hr of MCAo and 22 hr of reperfusion. Experimental TIAs reduced infarct volumes by 55% (P < 0.05), inhibited DNA fragmentation, and improved neurological outcome by 50% (P < 0.05) after ischemic stroke. EPO and its receptor were up-regulated by IP in the ipsilateral hemisphere by 24 hr after IP, before ischemic stroke and soluble EPO receptor attenuated neuroprotection by IP (88% reduction, P < 0.05). Pretreatment with the PI-3 kinase inhibitor wortmannin abolished the protective effect of IP against ischemic injury (P < 0.05). IP may be mediated in part by EPO through a PI-3 kinase pathway.     

~1H-magnetic resonance spectroscopy of vascular endothelial growth factor-induced neuroprotection following acute cerebral ischemia and reperfusion

BACKGROUND： It has become generally accepted that measuring N-acetyl-L-aspartic acid through the use of 1H-magnetic resonance spectroscopy （1H-MRS） could be used to evaluate neuronal injury. OBJECTIVE： To study metabolic changes of N-acetyl-L-aspartic acid surrounding the acute cerebral ischemia area following vascular endothelial growth factor （VEGF） treatment using 1H-MRS imaging, and to evaluate the neuroprotective effects of VEGE DESIGN, TIME AND SETTING： Randomly controlled animal study, according to one-factor analysis of variance, was performed at the Shenzhen Hospital of Peking University and State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences from August 2003 to December 2005. MATERIALS： Twelve healthy, adult, Sprague Dawley rats were used to establish an ischemia/reperfusion model through the use of middle cerebral artery occlusion. The 4.7T superconducting nuclear magnetic resonance meter was provided by Brucker Company. VEGF164 was purchased from Shenzhen Jingmei Bioengineering Co., Ltd. Titus anesthesia machine was purchased from Draeger Medical AG ＆ Co. KG METHODS： The rats were randomly divided into model control （n = 6） and VEGF-injected （n = 6） groups. All animals received 60-minute middle cerebral artery occlusion and 24-hour reperfusion. Lateral cerebral ventricle injection was performed by stereotaxic technique at respective time points. The VEGF group received 0.1 μg/μL L VEGF （5 μ L）, and the model group received the same amount of normal saline, once daily for 3 days. MAIN OUTCOME MEASURES： Metabolic changes of N-acetyl-L-aspartic acid and lactic acid following cerebral ischemia and reperfusion were detected using 1H-MRS, and the ischemic volume was measured. RESULTS： Twelve rats were included in the final analysis.1H-MRS results revealed that the ischemic volume increased in the control group compared with prior to injection （P 〈 0.01）. In the contro     

脑缺血耐受大鼠脑组织血管内皮生长因子和血管生成素-1表达的改变及其意义

目的探讨血管内皮生长因子(VEGF)和血管生成素-1(Ang-1)在短暂性脑缺血预处理(IP)诱导的脑缺血耐受大鼠脑组织表达的改变及其意义。方法将99只Wistar大鼠随机分成对照组(9只)、非IP(NIP)组(45只)和IP组(45只)。大脑中动脉线栓法建立局灶性IP模型,NIP组以假手术代替预缺血,分别在IP后1、3、7、14、21 d予以缺血2 h、再灌注22 h,对照组2次均为假手术。大鼠处死前给予神经功能缺损评分(NDS),采用TTC染色测定脑梗死体积,免疫组化染色法检测脑组织VEGF、Ang-1蛋白表达。结果对照组大鼠脑组织无梗死灶,NDS为0。IP 1、3、7 d亚组NDS和梗死体积显著小于NIP组1、3、7 d亚组(P<0.01～0.05),其中IP 3 d亚组NDS最低,梗死体积最小。对照组脑组织少量VEGF蛋白表达,IP 1、3、7 d亚组VEGF蛋白表达显著高于NIP 1、3、7 d亚组(均P<0.05),其中IP 3 d亚组VEGF蛋白表达最高。各组脑组织均有一定程度Ang-1蛋白表达,IP 7 d亚组Ang-1蛋白表达高于NIP 7 d亚组(P<0.05)。结论 IP 1～7 d内脑组织VEGF、Ang-1表达增加,对脑缺血耐受的产生具有重要作用。     

急性缺血性脑血管病患者血清血管内皮生长因子含量动态变化及其意义

目的　探讨血管内皮生长因子 (vascularendothelial growth factor,VEGF)在缺血性脑血管病患者血清中含量的动态变化 ,讨论血管内皮生长因子含量动态变化的意义及与梗死面积的关系。方法　将 46例急性缺血性脑血管病患者作为观察组 ,3 9例正常人为对照组。在急性缺血性脑血管病患者发病的 1、7、1 4d做血清 VEGF含量测定 ,并且对患者进行梗死面积测定。从而比较 VEGF含量与梗死面积的关系。结果　急性缺血性脑血管病患者 VEGF含量在 1、7、1 4d皆高于正常人 ,发病第 7天 VEGF含量最高 ,并且一直持续到发病后 1 4d仍高于正常人。 VEGF含量与梗死面积有一定相关性。结论　急性缺血性脑血管病患者血清中 VEGF含量明显增高。缺血性脑血管病患者梗死面积与 VEGF的含量有密切关系。     

局灶性缺血预处理对脑缺血大鼠血管内皮生长因子表达及血管形成的影响

目的：探讨血管内皮生长因子（VEGF）在脑缺血耐受中的作用及其与血管形成的关系。方法：Wistar大鼠线栓法阻塞大脑中动脉建立局灶性缺血预处理模型,并进行神经功能评分。随机分为假手术（对照组）、非缺血预处理（NIP）组和缺血预处理（IP）组,NIP和IP组再根据不同时间窗随机分成5个亚组。分别在缺血预处理后1、3、7、14和21 d进行再次缺血2 h再灌注22 h,然后取脑检测：TTC染色测定脑梗死体积,计数微血管密度,免疫组化检测CD34和VEGF蛋白表达,原位杂交法检测VEGF mRNA表达。结果：①组间比较：IP 1、3和7 d亚组脑梗死体积较NIP组明显减小（P〈0.01）,其神经行为缺损评分也明显降低（P〈0.05）;IP 3和7 d亚组脑微血管密度明显增高（P〈0.05）;IP 1、3和7 d亚组VEGF蛋白及mRNA表达明显增高（P〈0.05,P〈0.01）。②组内比较：IP 7 d亚组微血管在缺血灶周边区分布最为密集,脑微血管密度明显高于同组内其他亚组（P〈0.05）;IP 3和7 d亚组VEGF蛋白表达明显增高,VEGF mRNA表达在IP 1 d即开始升高,高峰出现在IP 3 d,持续至7 d。结论：缺血预处理诱导了脑缺血耐受,缺血预处理诱导的VEGF表达增加以及血管形成在脑缺血耐受中发挥重要作用。     

7蛋白酶体抑制剂对星形胶质细胞周期素D1和周期素依赖性激酶4表达的影响

目的：研究蛋白酶体抑制对体外培养的星形胶质细胞周期素Dl（cyclinD1）和周期素依赖性激酶4（CDK4）表达的影响。方法：SD乳鼠皮质星形胶质细胞原代培养,并纯化鉴定;予不同浓度（2和4μmol·L^-1）的蛋白酶体抑制剂（lactacystin）对第二代星形胶质细胞进行短期（12h）急性干预处理,应用免疫荧光及Westernblot检测星形胶质细胞cyclinD1和CDK4表达的水平。结果：纯化传代的皮质星形胶质细胞经胶质纤维酸性蛋白（GFAP）免疫荧光鉴定,其阳性率可达99％;lactacystin2和4μmol·L^-1可诱导星形胶质细胞cyclinDl和CDK4表达的下降,与对照组相比差异有显著统计学意义（P〈0．01）。结论：一定程度蛋白酶体活性抑制可诱导培养的星形胶质细胞cyclinD1和CDK4表达的减少,从而影响胶质细胞细胞周期,促进胶质细胞分化。提示蛋白酶体功能障碍后可能通过影响胶质细胞细胞周期来参与阿尔茨海默病的病理改变。     

Soluble VEGFR1 (sVEGFR1) as a novel marker of amyotrophic lateral sclerosis (ALS) in the North Indian ALS patients

Background and purpose: North Indian patients with amyotrophic lateral sclerosis (ALS) exhibit substantially extended survival time after onset of the disease as compared to their Western counterparts. Earlier, we found that vascular endothelial growth factor‐A (VEGF‐A) may be associated with increased survival of these patients. We now measured soluble vascular endothelial growth factor receptor‐1 (sVEGFR1), an inhibitor receptor for VEGF‐A, in these patients with ALS. Methods: Patients with sporadic ALS (n = 36) attending the Neurology Outpatient at Post Graduate Institute of Medical Education and Research (PGIMER) at Chandigarh were included on the basis of El Escorial criteria. The sVEGFR1 levels were analyzed in serum of these patients using enzyme‐linked immunosorbent assay (ELISA) and compared with normal controls (n = 36). Results: Soluble vascular endothelial growth factor receptor‐1 was found to be decreased significantly in serum of patients with ALS. Serum obtained from definite ALS revealed significantly lower sVEGFR1 as compared to probable ALS. However, there was no difference in serum sVEGFR1 levels between male and female patients with ALS. Conclusions: Soluble vascular endothelial growth factor receptor‐1 downregulation may result in increased serum VEGF‐A reported previously in our patients with ALS and may indicate the activation of compensatory mechanism in response to neurodegeneration. The lower serum sVEGFR1 levels may have a possible clinicopathological association, if not causal, to the extended survival of North Indian patients with ALS; however, the result needs further investigations particularly in comparable Caucasian ALS population.     

The NADPH oxidase Nox2 regulates VEGFR1/CSF‐1R‐mediated microglial chemotaxis and promotes early postnatal infiltration of phagocytes in the subventricular zone of the mouse cerebral cortex

The phagocyte NADPH oxidase Nox2 generates superoxide ions implicated in the elimination of microorganisms and the redox control of inflammatory signaling. However, the role of Nox2 in phagocyte functions unrelated to immunity or pathologies is unknown. During development, oriented cell migrations insure the timely recruitment and function of phagocytes in developing tissues. Here, we have addressed the role of Nox2 in the directional migration of microglial cells during development. We show that microglial Nox2 regulates the chemotaxis of purified microglia mediated by the colony stimulating factor‐1 receptor (CSF‐1R) and the vascular endothelial growth factor receptor‐1 (VEGFR1). Stimulation of these receptors triggers activation of Nox2 at the leading edge of polarized cells. In the early postnatal stages of mouse brain development, Nox2 is activated in macrophages / microglial cells in the lateral ventricle or the adjacent subventricular zone (SVZ). Fluorescent microglia injected into the lateral ventricle infiltrate the dorso‐caudal SVZ through a mechanism that is blocked by pretreatment of the injected cells with an irreversible Nox inhibitor. Infiltration of endogenous microglia into the caudal SVZ of the cerebral cortex is prevented by (1) Nox2 gene deficiency, (2) treatment with a Nox2 inhibitor (apocynin), and (3) invalidation of the VEGFR1 kinase. We conclude that phagocytes move out of the lateral ventricle soon after birth and infiltrate the cortical SVZ through a mechanism requiring microglial Nox2 and VEGFR1 activation. Nox2 therefore modulates the migration of microglia and their development.     

胰岛素样生长因子-1神经保护作用的研究进展

胰岛素样生长因子－1（Insulin-like growth factor-1，IGF-1）是一种与机体组织分化、增殖和成熟有关的重要细胞因子。IGF-1与其受体结合具有促进细胞分化增殖、抑制凋亡和类胰岛素的代谢作用，并还可能与其他神经营养因子协同发挥神经保护作用。其中，IGF-1保护缺血性脑损伤的可能机制有：甘氨酸-脯氨酸-谷氨酸（glycine-proline-glutamate，GPE）对神经细胞的保护作用、抗凋亡作用、阻止L型钙通道的开放、对一氧化氮合酶（NOS）的双重作用以及对抗兴奋性氨基酸的毒性等。随着临床实验的开展，IGF-1有可能作为脑保护剂用于缺血性脑损伤的治疗。