大鼠持续性脑缺血后小胶质细胞变化及其与神经元凋亡的关系

目的 研究成年大鼠持续性局灶脑缺血后小胶质细胞的变化及其与缺血后凋亡的关系。方法 采用单侧大脑中动脉近端民凝术建立成年大鼠持续性局灶脑缺血模型。在手术后3h、6h、12h、24h、48h、72h和120h取材,分别用IsolectinB4凝集素标记小胶质细胞和原位末端TUNEL法标记凋亡细胞。结果 缺血后凝集素阳性小胶质细胞和TUNEL阳性小胶质细胞都分布在梗死灶周边区。缺血12h在梗死灶的边缘密集分布凝集素标记阳性细胞,24－72h凝集素阳性小胶质细胞数量增加（P＜0．05）,120h阳性细胞数量减少（P＜0．01）。脑缺血48h、72h、120h在梗死灶边缘区域分布TUNEL阳性凋亡细胞,TUNEL阳性细胞以神经细胞为主。结论 持续性局灶脑缺血后活化小胶质细胞主要分布在梗死灶周边区,可能对缺血后神经元凋亡产生作用。     

胰岛素对大鼠脑缺血再灌注后Bcl-2表达及细胞凋亡的影响

目的 探讨胰岛素对大鼠脑缺血再灌注后Bcl-2表达及细胞凋亡的影响.方法 将动物随机分为假手术组、缺血组及干预组,参照Zea Longa线栓法建立大鼠左侧大脑中动脉闭塞(middle cerebral artery occlusion,MCAO)再灌注模型,干预组大鼠在脑缺血即刻给予胰岛素及葡萄糖腹腔注射,分别在左侧MCAO2h再灌注不同时间点断头取脑,脑皮质神经元Bcl-2的表达通过免疫组化法来测定,并采用TUNEL法原住标记DNA片段,检测TUNEL阳性细胞的变化.结果 缺血组大鼠脑皮质Bcl-2的表达较假手术组显著增强(P＜0.01),TUNEL阳性细胞数较假手术组显著增多(P＜0.01);给予胰岛素处理后,Bcl-2的表达较缺血组显著增强(P＜0.01),TUNEL阳性细胞数较缺血组明显减少(P＜0.01),但两者均显著高于假手术组(P＜0.01).结论 短暂的脑缺血再灌注可导致脑皮质神经元中Bcl-2的表达增加,抗细胞凋亡;胰岛素可上调脑皮质神经元中Bcl-2的表达,发挥神经保护作用.     

银杏叶提取物对大鼠脑缺血再灌注后GFAP和细胞凋亡的影响

目的 研究银杏叶提取物(EGb761)对大鼠局灶性脑缺血再灌注后神经细胞凋亡和星形胶质细胞表达的变化.方法 雄性SD大鼠随机分为假手术组、单纯缺血组、EGb761干预组,线栓法建立大脑中动脉缺血再灌注模型(MCAO),原位末端标记(TUNEL)法观察神经细胞的凋亡情况,免疫组化法观测星形胶质细胞的表达.结果 与单纯缺血...     

血管性认知障碍小鼠脑内少突胶质细胞再生分化障碍特点研究

目的 观察血管性认知障碍小鼠模型中,缺血性炎性损伤对室管膜下区及海马齿状回少突胶质细胞 再生分化的影响,为血管性认知障碍的缺血性炎症机制提出新的损伤途径。 方法 成年雄性CD1小鼠随机分为模型组和假手术组,每组24只,模型组采用双侧颈动脉反复缺 血再灌注法制备血管性认知障碍小鼠模型。造模后4～6 d连续腹腔注射5 -溴脱氧尿嘧啶核苷 （bromodeoxyuridine,BrdU）（150 mg/kg）标记新生细胞,分别于术后14 d和28 d每组随机取一半小鼠脑 组织进行脑切片免疫组化、免疫荧光双标共聚焦检测,标记脑组织室管膜下区和海马区的少突胶质 细胞、星形胶质细胞及神经元,观察新生少突胶质细胞增殖及分化情况,并观察星形胶质细胞的增 生活化情况。 结果 造模后14 d和28 d室管膜下区新生细胞（BrdU阳性细胞）在模型组较假手术组明显增加（P均 ＜0.001),造模28 d模型组新生神经元（BrdU/NeuN阳性细胞）较假手术组显著增加（P＜0.001)。与假 手术组相比较,术后28 d模型组海马齿状回少突胶质细胞祖细胞显著增多（P＜0.001）;少突胶质细 胞前体细胞显著减少（P =0.006）。造模后28 d模型组海马齿状回新生星形胶质细胞（BrdU/GFAP阳性 细胞）较假手术组显著增加（P =0.015）。 结论 血管性认知障碍小鼠内源性新生细胞增殖区室管膜下区与海马齿状回区均存在新生细胞反 应性增生的情况。新生细胞区分化的主要细胞为星形胶质细胞,而少突胶质细胞分化障碍,可能是血 管性认知障碍患者影像学常见皮层下白质病变的重要原因。     

pHGF对脑缺血再灌注大鼠bc1-2、p53表达的影响

目的 探讨促肝细胞生长因子(pHGF)对脑缺血再灌注损伤神经元的抗凋亡作用及机制.方法 36只健康雄性Wistar大鼠,随机分为缺血对照组和pHGF治疗组,再随机分为再灌注6h、12h、24h组3个亚组.采用动脉线栓法建立大鼠脑缺血再灌注模型,于各观察时间点处死大鼠取脑组织制切片,应用TUNEL法和免疫组化法检测神经元凋亡及bc1-2、p53蛋白表达情况.结果 各观察时间点,pHGF治疗组凋亡细胞数及p53蛋白阳性细胞数较缺血对照组明显减少(P＜0.05),pHGF治疗组bcl-2蛋白阳性细胞数较缺血对照组明显增多(P＜0.01).结论 pHGF具有抑制脑缺血再灌注损伤神经元凋亡的作用,其作用机制与调节bc1-2、p53蛋白表达有关.     

星形胶质细胞源性因子对神经干细胞分化的实验研究

目的探讨星形胶质细胞源性因子对神经干细胞分化的影响。方法分离和培养新生大鼠脑组织的神经干细胞;采用差速贴壁法和振荡法分离纯化星形胶质细胞,用免疫细胞化学染色法,胶质纤维酸性蛋白(GFAP)标记星形胶质细胞,进行细胞的纯度鉴定;将星形胶质细胞和神经干细胞在互不接触的情况下进行共培养,免疫荧光法观察神经干细胞分化后神经元特异性烯醇化酶(NSE)、GFAP和酪氨酸羟化酶(TH)的表达。结果纯化的星形胶质细胞GFAP抗体标记阳性,细胞纯度达98%;星形胶质细胞与神经干细胞共培养时,神经干细胞贴壁分化加快,NSE阳性细胞及TH阳性细胞明显多于对照组(P<0·05)。结论星形胶质细胞源性因子可快速诱导神经干细胞向神经元细胞、包括多巴胺神经元细胞分化,提示星形胶质细胞支持神经元发生。     

缺血预处理后海马CA1区反应性星形胶质细胞增生与迟发性神经元缺血耐受性的关系

目的 探讨缺血预处理后海马CA1区反应性星形胶质细胞增生与迟发性神经元缺血耐受性的关系。方法 实验动物被随机分为手术组、缺血组、预缺血组、预缺血后再缺血组。阴断沙土鼠双侧颈总动脉造成前脑缺血模型。采用细胞特异性抗原胶质纤维酸性蛋白（GFAP）免疫组化法标记星形胶质细胞。结果 预缺血后1－7天,海马CA1区GFAP阳性的星形胶质细胞数轻度增加,至28天时增生非常显著（P＜0．01）。预缺血后1－7天再缺血,海马CA1区存活正常神经元数逐渐下降,预缺血后28天再缺血又显著增加（P＜0．01）。结论 缺血预处理后,神经元可出现迟发性缺血耐受,反应性星形胶质细胞增生可能起了重要作用。     

大鼠脑缺血再灌注后神经细胞的细胞周期特征的比较研究

目的比较观察大鼠局灶性脑缺血后星形胶质细胞和神经元细胞周期的变化特征。方法采用线栓法大鼠大脑中动脉栓塞模型,利用流式细胞技术检测假手术组和缺血再灌注后不同时间点各组大脑皮层和海马中星形胶质细胞和神经元细胞周期的异常激活和动态变化。结果缺血后大脑皮层中神经元24h时即发生明显细胞周期变化,而3d时进入细胞周期的星形胶质细胞才明显增加;海马中星形胶质细胞却先于神经元进入细胞周期,于24h时细胞周期即发生明显变化,与假手术组比较有显著差异(P<0.01)。结论在不同脑区星形胶质细胞和神经元两者对缺血性脑损伤的敏感性互不相同,并且不同脑区的星形胶质细胞对缺血性脑损伤的敏感性也有不同,脑缺血后2种细胞均出现细胞周期的异常激活。     

大鼠脑缺血再灌注损伤后的细胞凋亡与Bcl-2、Bax的表达

目的:观察脑缺血再灌注损伤中的细胞凋亡与Bcl2家族的关系。方法:参照ZeaLonga线栓法制作急性大鼠大脑中动脉缺血再灌注模型,观察脑缺血再灌注后大鼠缺血脑组织中的凋亡细胞变化情况及Bcl2、Bax蛋白表达情况,同时通过透射电镜观察缺血侧脑组织神经元超微结构变化。结果:同对照组相比缺血再灌注组凋亡神经元细胞增多(TUNEL阳性细胞)(P<0.05);Bax、Bcl2阳性细胞均升高(P<0.01),同时Bcl2/Bax比值降低;电镜观察神经元超微结构出现凋亡早期改变。结论:Bcl2/Bax比值影响脑缺血再灌注损伤后细胞凋亡。     

氧糖剥夺/复氧损伤后星形胶质细胞iNOS的表达及胍丁胺的干预作用研究

目的 观察星形胶质细胞缺血再灌注损伤后iNOS的表达及胍丁胺的干预作用.方法 体外缺血再灌注诱导损伤原代培养的星形胶质细胞,检测培养液中乳酸脱氢酶(lactate dehydrogenase,LDH)漏出量,并利用流式细胞术检测细胞凋亡和/或坏死率,同时测定NO生成量和诱导型一氧化氮合酶(inducible NOS,iNOS)的表达.结果 胍丁胺显著提高缺血再灌注损伤细胞的存活率,降低细胞IJDH漏出量.流式细胞仪分析显示胍丁胺主要是降低细胞坏死率而对凋亡率则无显著性影响.与阳性对照组相比,胍丁胺显著降低星形胶质细胞缺血再灌注损伤引起的NO产量,同时也减少了iNOS表达.结论 胍丁胺对星形胶质细胞缺血再灌注损伤具有保护作用,其可能的作用机制是降低iNOS、抑制炎症因子NO合成,从而降低星形胶质细胞的炎症坏死.     

Apoptosis and expression of p53 response proteins and cyclin D1 after cortical impact in rat brain

We measured the temporal profile and cellular identification of apoptosis in rat brain after cortical contusion injury. Double staining immunohistochemistry was also used to investigate the relationship between apoptotic cell death and selective protein expression associated with DNA damage and repair (p53, Bax, MDM2, WAF1, Gadd45, PCNA) and cell cycle protein, Cyclin D1, in male Wistar rats 48 h after injury. Cortical contusion was induced in male Wistar rats with a pneumatic impactor device. The animals were sacrificed at different times after trauma (1, 2, and 14 h and 1, 2, 4, 7 and 14 days; n=4 per time point). Sham-operated rats (n=4) and normal rats not subjected to any surgical procedure (n=4) were used as controls for temporal profile determination. Additional 11 rats were used for study of protein expression. Coronal brain sections were analyzed using an in situ terminal deoxynucleotdyl transferase-mediated biotinylated deoxyuridine triphosphate nick end labeling (TUNEL), hematoxylin, and immunohistochemical double staining methods. Apoptotic cells were observed as early as 2 h after the impact. Apoptotic cell death peaked at 2 days, gradually tapering off afterward, although scattered apoptotic cells were detected at 2 weeks after the impact. The number of apoptotic cells at 2 days far exceeded their number at other times (p=0.009). Apoptotic cells were observed primarily in the cortex adjacent to the site of injury. In addition, apoptotic cells in conjunction with few injured cells were present in the ipsilateral hippocampus and localized to the granule layer of dentate gyrus. Our data indicate that DNA fragmentation is present in nearly all neurons subacutely after cortical contusion and persists for at least 2 weeks thereafter. Apoptosis is also present in neurons localized to the hilus of the dentate gyrus at a site remote from the area of injury suggesting a selective role for apoptosis in promoting secondary brain damage and dysfunction after traumatic brain injury. Using double staining, we were able to show that a great majority of apoptotic cells (>95%) were neurons and the rest were astrocytes and endothelial cells. Proteins associated with DNA damage and repair (p53, Bax, MDM2, WAF1, Gadd 45, PCNA) were expressed in the cytoplasm of normal cells of naive and sham rats. These proteins were translocated to the nuclei of apoptotic and injured cells at 48 h after cortical contusion. Cyclin D1 was not present in apoptotic cells. The differential expression of proteins associated with DNA damage, repair and the cell cycle protein Cyclin D1 in the contused brain suggest a potential role for these proteins in cell survival and apoptosis after cortical contusion.     

Aluminum-induced apoptosis in cultured astrocytes and its effect on calcium homeostasis

Aluminum exposure and apoptotic cell death has been implicated in several neurodegenerative conditions including Alzheimer's disease. In this study, we use cultured astrocytes to investigate the ability of aluminum to induce the apoptosis of astrocytes. The proportion of apoptotic cells and cell cycle distribution were determined by flow cytometric analysis. Our results showed that exposure to aluminum at low levels (100 and 200 microM) for up to 6 days did not result in the apoptosis of astrocytes, and a dramatic blockage of apoptotic cells was found at 200 microM aluminum. However, at 400 microM, aluminum markedly induced the apoptosis of astrocytes, which was associated with a significant change in cell cycle distribution characterized by increase of G2/M phase cells (128%). Measurements of intracellular Ca(2+) concentration using the fluorescent calcium indicator dye Fluo-3 demonstrated a significant increase in the levels of intracellular calcium after aluminum treatment. However, no differences were observed among aluminum-treated groups. These findings suggest that aluminum induce and block selectively the apoptosis of astrocytes, which depend upon the concentrations of aluminum. Increased intracellular Ca(2+) may not be the primary mechanism of aluminum-mediated apoptotic cell death.     

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     

颅咽管瘤细胞周期特点及其临床意义

目的 检测颅咽管瘤(CP)的细胞增殖、凋亡指数及细胞周期动力学特点,观察与肿瘤复发的关系.方法 采取前瞻性队列研究方案,流式细胞技术(FCM)检测肿瘤细胞的染色体变化及增殖、凋亡分数,测定CP组织细胞s期分数,Tanel·POD法测定肿瘤细胞凋亡,结合电镜观察肿瘤超微结构及与周界正常组织关系,评价CP亚型釉质上皮型/鳞形上皮型、复发组/非复发组、原发组/复发组间瘤细胞周期动力学特点.结果 CP细胞为二倍体,釉质上皮型肿瘤实质部分坏死、凋亡率小于鳞形上皮瘤实质成分(P<0.05),但二型肿瘤细胞凋亡率均较低下;釉质上皮型肿瘤细胞较鳞形上皮型增殖活性强,前者S期分数、G2/M+s值也显著高于后者,釉质上皮瘤、鳞形上皮瘤复发组和非复发组比较也得出类似结果(P相似文献   

Quantification of sPLA2-induced early and late apoptosis changes in neuronal cell cultures using combined TUNEL and DAPI staining

The terminal deoxynucleotidyl transferase (TdT) dUTP nick end labeling (TUNEL) stain is in wide use for measuring apoptosis in neurons, as well as in other cell types. TUNEL may give false positive results due to variations in labeling technique as well as staining of cells that have undergone non-apoptotic DNA strand breaks. Therefore, in isolation, TUNEL is not a certain indicator of apoptosis. Recently, we have demonstrated the potent apoptotic effect of secreted phospholipase A2 from group III (sPLA2-III) on primary cortical neurons from rat. Here we describe a computer-assisted method for quantifying TUNEL-positive neurons after sPLA2-III induced apoptosis. Extent of TUNEL is normalized to total nuclear content using 4',6-diamidino-2-phenylindole (DAPI) staining. Furthermore, DAPI counterstaining allows for determination of a nuclear morphology indicator, based on nuclear size and roundness, which we call the nuclear area factor. We found that the nuclear area factor is an early indicator of cell death (significant after 4 h post treatment), while TUNEL staining is significant at later times (26 h). Thus, the independent staining techniques using TUNEL and DAPI complement each other, and with commercially available image analysis software, may be used to indicate early as well as delayed cell injury processes.     

Coexpression of Fas/FasL and Bax on brain and infiltrating T cells in the central nervous system is closely associated with apoptotic cell death during autoimmune encephalomyelitis

Recent studies have suggested that autoimmune inflammation elicited in the central nervous system (CNS) is subsided by apoptotic cell death of inflammatory cells. To elucidate the molecular mechanism of apoptosis of infiltrating T and other cells occurring in the CNS during autoimmune encephalomyelitis, we determined the type of apoptotic cells and the localization of apoptosis-related molecules (Fas, FasL, Bax, Bcl-2 and active caspase 3) by immunohistochemistry. Double labeling with the TUNEL method and cell-type markers showed that infiltrating T cells and microglia/macrophages underwent apoptosis, while astrocytes and neurons did not. Staining for apoptosis-related molecules revealed that infiltrating T cells and microglia/macrophages, but not astrocytes and neurons, expressed both Fas-FasL and Bax. The distribution and cell type of active caspase 3-positive cells were essentially the same as those of TUNEL-positive cells. These findings suggest that coexpression of Fas/FasL and Bax is closely associated with apoptotic cell death of infiltrating T cells and microglia in the CNS. Furthermore, astrocytes which express Fas and FasL, but not Bax, may play an important role in regulating inflammation in the CNS by inducing apoptotic cell death of infiltrating T cells and microglia, both of which have an inflammation-promoting nature.     

阿尔茨海默病脑海马凋亡神经元发生率增高

通过对阿尔茨海默病 (Alzheimer’sdisease ,AD)和老年对照患者死后脑海马凋亡神经元的检测 ,探讨AD脑神经元丢失的可能机制。使用TUNEL(terminaltransferase mediateddUTP biotinnickendlabeling)法对 7例确诊的AD和 9例老年对照患者死后海马组织中的凋亡神经元进行标记 ,用生物图像分析系统对结果进行定量分析。AD和对照组间TUNEL阳性细胞数无显著性差异 ;AD组海马CA1和CA4区正常神经元数减少 ,其中CA1区减少具有显著性差异 (P <0 .0 5 ) ;AD组海马CA1和CA4区凋亡神经元发生率高于对照组 ,其中CA1区具有显著性差异 (P <0 .0 5 )。AD组海马组织中凋亡神经元发生率明显增高 ,说明细胞凋亡可能参与了AD海马神经元退行性变的过程。     

Characterization of Bax and Bcl-2 in apoptosis after experimental traumatic brain injury in the rat

This study was undertaken to fulfill the need for additional data on the dynamics of Bax and Bcl-2 expression in conjunction to the cell death that ensues following experimental brain contusion. Adult Sprague-Dawley rats were subjected to a unilateral experimental controlled cortical contusion and killed at 1, 2, 4, 6 and 10 days post injury (dpi). Cell death was examined by the terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) method together with immunohistochemistry for cellular markers. Expression of Bax and Bcl-2 were analyzed by immunohistochemistry and in situ hybridization. The number of TUNEL-positive cells was highest at 1 dpi and decreased with time. At all time points, 10-16% of the TUNEL-positive cells showed an apoptotic nuclear morphology. The apoptotic features were restricted to neurons and some inflammatory cells. Immunohistochemistry for Bax revealed a translocation of Bax from a diffuse to a granular distribution in neurons. An up-regulation of Bax mRNA at 6 dpi was discernible. This increase was associated with a statistically significant increase in number of cells with up-regulated and translocated Bax protein. Moreover, a statistically significant increase of Bcl-2 mRNA was detected at 10 dpi. The potential window for anti-apoptotic treatment to salvage neurons is wide. The susceptibility of neurons to necrosis and apoptosis through different pathways during a prolonged post-traumatic period indicate that different pharmacological strategies may be required at different time points after trauma.     

小鼠皮质神经元类缺血/再灌注后氟桂利嗪对胞质内游离钙离子和神经元凋亡的实验研究

目的研究类缺血/再灌注后不同时间点神经元胞质内游离钙离子及神经元凋亡比例变化,探讨类缺血/再灌注后神经元的凋亡与神经内钙离子的关系及氟桂利嗪的治疗意义.方法利用Ca2 指示剂Flu-3/AM作为细胞内钙离子的荧光探针负载培养的神经元,共聚焦技术检测细胞内荧光强度的变化,原位末端标记法(TUNEL)观察神经元类缺血再灌注后不同时间点神经元凋亡情况.结果与类缺血/再灌注组相比,氟桂利嗪对类缺血/再灌注后神经元胞质内游离钙离子浓度增高和神经元凋亡有显著抑制作用(P＜0.05);再灌注3 h两组无显著差异.结论氟桂利嗪可明显抑制类缺血/再灌注后神经元胞质内钙离子的升高,减少神经元凋亡比例.     

Unexpected BrdU inhibition on astrocyte-to-neuron conversion

5-Bromo-2′-deoxyuridine(BrdU)is a halogenated pyrimidine that can be incorporated into newly synthesized DNA during the S phase of the cell cycle.BrdU is widely used in fate-mapping studies of embryonic and adult neurogenesis to identify newborn neurons,however side effects on neural stem cells and their progeny have been reported.In vivo astrocyte-to-neuron(AtN)conversion is a new approach for generating newborn neurons by directly converting endogenous astrocytes into neurons.The BrdU-labeling strategy has been used to trace astrocyte-converted neurons,but whether BrdU has any effect on the AtN conversion is unknown.Here,while conducting a NeuroD1-mediated AtN conversion study using BrdU to label dividing reactive astrocytes following ischemic injury,we accidentally discovered that BrdU inhibited AtN conversion.We initially found a gradual reduction in BrdU-labeled astrocytes during NeuroD1-mediated AtN conversion in the mouse cortex.Although most NeuroD1-infected astrocytes were converted into neurons,the number of BrdU-labeled neurons was surprisingly low.To exclude the possibility that this BrdU inhibition was caused by the ischemic injury,we conducted an in vitro AtN conversion study by overexpressing NeuroD1 in cultured cortical astrocytes in the presence or absence of BrdU.Surprisingly,we also found a significantly lower conversion rate and a smaller number of converted neurons in the BrdU-treated group compared with the untreated group.These results revealed an unexpected inhibitory effect of BrdU on AtN conversion,suggesting more caution is needed when using BrdU in AtN conversion studies and in data interpretation.