银杏叶提取物对局灶性脑缺血再灌注后GFAP表达的影响

目的研究银杏叶提取物(extract of Ginkgo biloba,EGB)对局灶性脑缺血再灌注后星形胶质细胞胶质纤维酸性蛋白(GFAP)表达的影响。方法大脑中动脉插线法制作大鼠局灶性脑缺血再灌注模型。75只Wistar大鼠随机分为假手术组、缺血再灌注组、EGB治疗组。缺血2h再灌注48h后,采用免疫组织化学法检测脑组织内GFAP蛋白的表达。结果缺血再灌注后可诱导脑组织GFAP表达增强,EGB可抑制缺血再灌注后GFAP的表达(P<0.05)。结论局灶性脑缺血再灌注后,可诱导脑组织GFAP表达增强,EGB可抑制脑缺血后星形胶质细胞GFAP的高表达,提示EGB可能对缺血诱导的星形胶质细胞活化具有抑制作用,这可能是EGB抗脑缺血损伤保护神经元作用的机制之一。     

银杏叶提取物对局灶性脑缺血再灌注不同时段的大鼠脑组织GFAP的影响

目的观察银杏叶提取物(extract of Ginkgo biloba,EGB)对大鼠局灶性脑缺血再灌注梗死区胶质纤维酸性蛋白(GFAP)表达的影响。方法采用改良线栓法建立大鼠大脑中动脉阻塞脑缺血再灌注模型。观察再灌注1～4d里大鼠神经功能缺损程度并应用免疫组织化学法、Metamoph图像分析系统对结果进行分析。结果EGB药物组神经功能评分较缺血再灌组好(P<0.05),GFAP阳性细胞于脑缺血2h再灌注24h后即已出现,48、72、96h阳性细胞表达量增加,其中以72h为最多,EGB可抑制缺血后GFAP的表达(P<0.05)。结论局灶性脑缺血后可诱导脑组织GFAP表达增强,EGB可抑制脑缺血再灌注后星形胶质细胞GFAP的高表达,提示EGB对缺血诱导的星形胶质细胞活化具有抑制作用,可能对脑缺血损伤的恢复起重要作用。     

L-电压门控钙通道在糖尿病大鼠局灶性脑缺血中的变化及意义

目的: 检测单纯局灶性脑缺血和糖尿病局灶性脑缺血大鼠不同时间L-电压门控钙通道电流的变化,通过比较探讨其在糖尿病局灶性脑缺血中的意义。方法: 应用高脂饮食联合链脲佐菌素(STZ)制备糖尿病大鼠模型,线栓法制备单纯局灶性脑缺血模型及糖尿病大鼠局灶性脑缺血模型,根据缺血不同时间分为正常假手术组、单纯脑缺血1 h、3 h、6 h、24 h;糖尿病假手术组、糖尿病脑缺血1 h、3 h、6 h、24 h共计10组。对单纯缺血24 h及糖尿病局灶性脑缺血24 h大鼠进行神经功能评分;应用全细胞膜片钳技术检测各组缺血周围皮层神经元细胞上电压门控钙通道电流的变化。结果: 糖尿病组大鼠术后清醒较晚,肢体偏瘫程度重于单纯缺血组(P<0.05);随着缺血时间的延长,单纯局灶性脑缺血及糖尿病局灶性脑缺血各组L-电压门控钙通道电流呈逐渐增大趋势(P<0.05),其中糖尿病局灶性脑缺血各组电压门控钙通道电流分别高于单纯局灶性脑缺血各组(P<0.05) 。结论: 与正常大鼠局灶性脑缺血相比,糖尿病大鼠局灶性脑缺血加重的原因可能与膜上钙通道开放电流增大导致的细胞内钙超载有关。     

依达拉奉联合灯盏花素对脑缺血大鼠大脑皮质MCP-1的影响

目的　观察大鼠脑缺血（MCAO）后大脑皮质MCP-1的表达变化以及用依达拉奉联合灯盏花素干预后对MCP-1表达的影响。 方法　复制大鼠大脑中动脉闭塞（MCAO）模型,应用RT-PCR、Western blot和免疫荧光技术检测大鼠MCAO及药物干预后MCP-1的表达变化。 结果　RT-PCR显示大鼠MCAO后大脑皮质MCP-1 mRNA的表达比对照组显著上升（P<0.05）,12 h达高峰,与1 d、3 d及1周组比有显著差异（P<0.05）;给予两种药物联合处理后,mRNA表达显著降低,与对照组及单独用药组相比均有显著差异（P<0.05）。 Western blot显示MCAO 1 d、3 d、1周大脑皮质MCP-1蛋白的表达显著增强,与对照组比有显著差异（P<0.05）;两种药物联合处理后,MCAO大鼠大脑皮质MCP-1蛋白表达明显减少,与对照组及单独用药相比均有显著差异（P<0.05）。免疫荧光染色显示MCAO大鼠缺血半暗带有大量激活小胶质细胞,一部分与MCP-1免疫阳性细胞有共表达,其中MCAO后1周组最明显。 结论　大鼠局灶性脑缺血（MCAO）后,依达拉奉联合灯盏花素治疗能有效减少大脑皮质MCP-1的表达,效果优于两种药物单独使用。     

慢性血管性痴呆模型大鼠脑胶质细胞反应及基质金属蛋白酶9的表达

背景：胶质细胞及炎性细胞因子参与了血管性痴呆慢性脑缺血的炎性反应过程。 目的：观察慢性脑缺血致血管性痴呆大鼠的脑组织中胶质细胞反应及基质金属蛋白酶9的表达。 方法：雄性Wistar大鼠随机分为正常组、假手术组和模型组3组。模型组通过永久性结扎大鼠的双侧颈总动脉导致慢性脑缺血建立动物模型,假手术组除不结扎双侧颈总动脉外,其余处理与模型组相同。各组大鼠行Morris水迷宫试验检测大鼠的学习记忆能力。采用病理染色、免疫组化的方法,观察大鼠在缺血后不同时间点脑组织中胶质细胞及基质金属蛋白酶9的病理改变。 结果与结论：缺血早期的病理变化主要发生在皮质、基底前脑、海马、胼胝体、颞叶皮质及视束,部分出现小的梗死灶。缺血1个月后,白质髓鞘脱失、间质疏松呈空泡样改变逐渐明显,神经轴索连续性完好。小胶质细胞、星形胶质细胞及基质金属蛋白酶9的表达在缺血早期以皮质及海马为主,缺血后期以室周白质及白质疏松处更为明显,海马区表达则减少。     

NGF对局灶性脑缺血再灌注大鼠海马和顶叶皮质内CREB mRNA表达的影响

探讨外源性神经生长因子(nervegrowthfactor,NGF)对局灶性脑缺血再灌注大鼠海马和顶叶皮质内的cAMP反应元件结合蛋白(cyclicAMPresponseelementbindingprotein,CREB)mRNA表达的影响。用线栓法制作大鼠局灶性脑缺血再灌注模型,运用原位杂交和图像分析技术检测大鼠缺血侧海马CA1区和顶叶皮质内CREBmRNA的表达。结果显示:缺血再灌注组缺血侧海马CA1区和顶叶皮质CREBmRNA阳性反应产物平均光密度(OD)比假手术组减少(P<0.05),NGF组CA1区和顶叶皮质内的CREBmRNA阳性产物平均光密度高于缺血再灌注组(P<0.05)。本研究结果提示NGF可以上调局灶性脑缺血再灌注大鼠海马和顶叶皮质缺血神经元CREBmRNA的表达,NGF对缺血神经元的保护作用可能通过激活CREB的转录与翻译,从而启动一系列信号通路来实现。     

NGF对局灶性脑缺血再灌注大鼠顶叶皮质CREB表达的上调作用

为探讨外源性神经生长因子(NGF)对局灶性脑缺血再灌注大鼠顶叶皮质cAMP反应元件结合蛋白(CREB)和磷酸化CREB(p-CREB)表达的影响,用线栓法制作局灶性脑缺血再灌注模型,应用免疫组织化学、WesternBlotting和图像分析方法检测大鼠缺血侧顶叶皮质CREB和p-CREB的表达。结果显示:缺血再灌注组CREB表达较假手术组减少,p-CREB表达高于假手术组(P<0.05);NGF组CREB和p-CREB表达高于缺血再灌注组(P<0.05)。以上结果表明NGF明显上调局灶性脑缺血再灌注大鼠顶叶皮质CREB和p-CREB的表达,NGF对缺血神经元的保护作用可能通过上调CREB和p-CREB的表达来实现。     

CGRP对局灶性脑缺血再灌注大鼠顶叶皮质CREB和p-CREB的上调作用

目的：探讨外源性降钙素基因相关肽（CGRP）对局灶性脑缺血再灌注大鼠顶叶皮质CREB和磷酸化CREB（p-CREB）表达的影响。方法:用线栓法阻塞大鼠右大脑中动脉制作局灶性脑缺血再灌注模型，应用免疫组织化学、Western blotting和图像分析方法检测大鼠手术侧顶叶皮质CREB和p-CREB表达。结果:缺血再灌注组大鼠顶叶皮质CREB表达少于假手术组，CGRP组大鼠顶叶皮质CREB表达多于缺血再灌注组（P<0.05）。假手术组右侧顶叶皮质p-CREB表达很少，缺血再灌注组顶叶皮质p-CREB表达多于假手术组，CGRP组p-CREB表达多于缺血再灌注组（P<0.05）。结论:CGRP上调局灶性脑缺血再灌注大鼠右侧顶叶皮质CREB和p-CREB的表达，CGRP对缺血神经元的保护作用可能是通过上调神经元内CREB和p-CREB来实现的。     

睫状神经营养因子对大鼠脑缺血后髓鞘再生的影响

目的:研究睫状神经营养因子(CTNF)对脑缺血大鼠胼胝体髓鞘再生的影响。方法:48只雄性SD大鼠随机分为假手术组(Sham)、双侧颈总动脉结扎(2-VO)组和CTNF治疗组(CTNF)。利用2-VO法制备大鼠脑缺血损伤模型,在术后24 h内用0. 4μg/kg的CTNF或生理盐水分别给予CTNF治疗组、2-VO组和Sham组大鼠尾静脉注射。给药7 d后通过神经缺损功能评分(NSS)和转棒实验(Rota-Rod)检测各组大鼠神经功能,电镜观察胼胝体内髓鞘超微结构的变化,通过免疫荧光染色观察少突胶质细胞转录因子2(Olig-2)的表达,Western Blot检测髓磷脂碱性蛋白(MBP)的表达。结果:与Sham组相比,2-VO组大鼠神经功能显著受损(P 0. 05);电镜下可观察到大鼠胼胝体髓鞘变薄、完整性差;胼胝体部位Olig-2表达显著减少; MBP表达显著下降(P 0. 05)。经CTNF治疗后7 d的大鼠出现神经功能明显改善(P 0. 05),胼胝体髓鞘结构明显恢复,Olig-2表达明显增加,MBP表达明显增加(P 0. 05)。结论:CTNF处理能够改善脑缺血大鼠神经功能,促进髓鞘再生。     

基因表达谱芯片筛选局灶性脑缺血大鼠脑相关基因的研究

目的:应用基因芯片技术研究局灶性脑缺血大鼠脑组织与假手术组大鼠脑组织基因表达谱的差异,探索局灶性脑缺血的发病机制。方法:将4096种大鼠基因PCR产物用CartesianPixsys7500点样仪按微矩阵排列制成基因芯片;按一步法抽提脑局灶性缺血大鼠脑组织与假手术组大鼠脑组织的总RNA;将等量的脑局灶性缺血大鼠脑组织与假手术组大鼠脑组织RNA分别逆转录合成以Cy5和Cy3标记的cDNA一链做探针,混合后与上述基因芯片杂交。用AxonGenepix4000B扫描仪扫描芯片荧光信号图像,用GenepixPro4.0软件进行数字化处理和分析后比较两种组织基因表达谱的差异。结果:局灶性脑缺血大鼠与假手术组大鼠脑组织基因表达谱分析,发现211个差异表达基因,其中12个基因低表达,199个基因高表达。结论:本研究从脑局灶性缺血大鼠脑组织中筛选出大量的差异表达基因,说明这些基因可能参与局灶性脑缺血后脑损伤的发生及发展过程,从而为局灶性脑缺血的诊治提供新思路。     

Acute Marchiafava-Bignami disease: diffusion-weighted MRI in cortical and callosal involvement

Marchiafava-Bignami disease (MBD) is a fatal disorder characterized by demyelination of the corpus callosum. MRI, suggestive of corpus callosum demyelination with associated white matter involvement in both cerebral hemispheres, indicates a diagnosis of MBD. In this case, MR diffusion-weighted findings taken at an acute stage of MBD revealed lesions not only in the corpus callosum but also in the cerebral cortex. Lower apparent diffusion coefficient values of the corpus callosum and cortical lesions were associated with poor clinical outcome.     

慢性全脑低灌注大鼠侧脑室旁白质改变及基质金属蛋白酶-2和7的表达

目的观察慢性全脑低灌注大鼠侧脑室旁白质改变及基质金属蛋白酶-2和7(MMP-2和MMP-7)的表达并探讨其意义。方法 Wistar雄性大鼠60只,随机分为假手术组和模型组(20d组、40d组、60d组)共4组。模型组行双侧颈总动脉分期永久结扎术制备慢性全脑低灌注模型。透射电镜观察胼胝体和内囊超微结构变化;胶质纤维酸性蛋白(GFAP)免疫组织化学染色观察星形胶质细胞变化;免疫印迹法检测髓鞘碱性蛋白(MBP)含量变化;免疫组织化学染色和免疫印迹法观察和检测MMP-2和7表达变化。结果电镜观察可见模型20d组侧脑室旁白质有髓纤维髓鞘发生变形、板层结构疏松、崩溃等脱髓鞘改变,血管周围有明显水肿现象,而假手术组未见明显变化。各模型组见星形细胞胞体肥大、突触增粗、数量增多,随低灌注时间延长GFAP表达增多,而MBP减少,较假手术组差异均有明显统计学意义(P0.01)。各模型组MMP-2和MMP-7表达均较假手术组增多(P0.01或P0.001),MMP-2和MMP-7表达与侧脑室旁白质损伤呈明显正相关。结论大鼠慢性全脑低灌注引起持续性的侧脑室旁白质缺血性损伤,MMP-2和MMP-7表达上调可能参与白质损伤的进展。     

基于纤维束空间统计学的吸烟成瘾青少年左右脑白质不对称研究

目的:观察吸烟成瘾青少年左右脑白质结构的不对称性变化。 方法:采用基于纤维束空间统计（TBSS）的分析方法,对23名青少年吸烟成瘾者的脑白质弥散张量成像（DTI）数据进行处理,观察分析出现左右脑白质结构异常不对称的脑区。 结果:通过分析,我们发现青少年成瘾者的脑白质在胼胝体部、胼胝体膝部、胼胝体压部、前放射冠、内囊前肢等脑区处的左右脑白质不对称差异值较大（FWE校正后P<0.05）。Pearson相关分析显示在胼胝体部（r=0.431, P=0.040）、胼胝体膝部（r=0.429, P=0.041）、前放射冠（r=0.477, P=0.021）这些脑区的轴向弥散率（AD）与尼古丁依赖量表（FTND）程度分数呈显著正相关,胼胝体压部与FTND呈显著负相关（r=-0.450, P=0.031）。胼胝体膝部的分数各向异性与FTND呈现显著正相关（r=0.678, P=0.000）。前放射冠的AD与吸烟指数包年（pack-year）呈现显著正相关（r=0.493, P=0.017）。 结论:青少年吸烟成瘾者的胼胝体,前放射冠等脑区的脑白质表现出了异常的左右不对称。     

Diazoxide and dimethyl sulphoxide alleviate experimental cerebral hypoperfusion-induced white matter injury in the rat brain

Aging and dementia are accompanied by cerebral white matter (WM) injury, which is considered to be of ischemic origin. A causal link between cerebral ischemia and WM damage has been demonstrated in rats; however, few attempts appear to have been made to test potential drugs for the alleviation of ischemia-related WM injury. We induced cerebral hypoperfusion via permanent, bilateral occlusion of the common carotid arteries of rats. A mitochondrial ATP-sensitive potassium channel opener diazoxide (5 mg/kg) or its solvent dimethyl sulphoxide (DMSO) was administered i.p. (0.25 ml) on 5 consecutive days after surgery. Sham-operated animals served as control for surgery, and non-treated rats as controls for treatments. Thirteen weeks after surgery, the animals were sacrificed and astrocytes and microglia were labeled immunocytochemically in the internal capsule, the corpus callosum and the optic tract. The astrocytic proliferation was enhanced by cerebral hypoperfusion in the optic tract, and reduced by diazoxide in DMSO, but not by DMSO alone in the corpus callosum. After carotid artery occlusion, microglial activation was enhanced two-fold in the corpus callosum and four-fold in the optic tract. DMSO decreased microglial activation in the optic tract, while diazoxide in DMSO, but not DMSO alone, restored microglial activation to the control level in the corpus callosum. In summary, the rat optic tract appeared to be particularly vulnerable to ischemia, while the effect of diazoxide was restricted to the corpus callosum. We conclude that diazoxide dissolved in DMSO can moderate ischemia-related neuroinflammation by suppressing glial reaction in selective cerebral WM areas.     

White matter damage of patients with Alzheimer’s disease correlated with the decreased cognitive function

Increasing evidence demonstrates that there is marked damage and dysfunction in the white matter in Alzheimer’s disease (AD). The present study investigates the nature of white matter damage of patients with Alzheimer’s disease with diffusion tensor magnetic resonance imaging (DTI) and analyses the relationship between the white matter damage and the cognition function. DTI, as well as T1 fluid attenuated inversion recovery (FLAIR) and T2-FLAIR, was performed on probable patients of Alzheimer’s disease, and sex and age matched healthy volunteers to measure the fractional anisotropy (FA) and mean diffusivity (MD) in the genu and splenium of the corpus callosum, anterior and posterior limbs of the internal capsule, and the white matter of frontal, temporal, parietal, and occipital lobes. FA was lower in the splenium of corpus callosum, as well as in the white matter of the frontal, temporal, and parietal lobes from patients with Alzheimer’s disease than in the corresponding region from healthy controls and was strongly positive correlated with MMSE scores, whereas FA appeared no different in the anterior and posterior limbs of internal capsule, occipital lobes white matter, and the genu of corpus callosum between the patients and healthy controls. MD was significantly higher in the splenium of corpus callosum and parietal lobes white matter from patients than in that those from healthy controls and was strongly negative correlated with MMSE scores, whereas MD in the anterior and posterior limbs of internal capsule, as well as in frontal, temporal, occipital lobes white matter and the genu of corpus callosum, was not different between the patients and healthy controls. The most prominent alteration of FA and MD was in the splenium of corpus callosum. Our results suggested that white matter of patients with Alzheimer’s disease was selectively impaired and the extent of damage had a strong correlation with the cognitive function, and that selective impairment reflected the cortico–cortical and cortico–subcortical disconnections in the pathomechanism of Alzheimer’s disease. The values of FA and MD in white matter, especially in the splenium of corpus callosum in AD patients, might be a more appropriate surrogate marker for monitoring the disease progression.     

大脑中央核心区白质纤维束解剖

目的采用Klingler纤维解剖技术显露大脑中央核心区白质纤维结构,对其进行系统性描述并测量相关结构。方法采用Klingler纤维解剖技术对8例(16侧)成人尸头标本进行解剖,对大脑中央核心区白质纤维束进行逐层分离,观察其走行特点、与周围结构的毗邻关系,并进行相应数据测量。结果采用Klingler纤维解剖技术可清晰显示大脑中央核心区白质纤维束的形态及其位置,最外囊、外囊与屏状核的相对关系,外囊、内囊与壳核的相对关系。经测量,胼胝体的平均长度与厚度分别为73.06 mm、6.85 mm,松果体与前连合的平均距离为28.01 mm,松果体与穹隆柱的平均距离为26.37 mm,穹窿与胼胝体的垂直距离仅为7.56 mm。结论运用Klingler纤维解剖技术可直观、清晰地显示大脑中央核心区白质纤维束的结构及位置,大脑中线上第三脑室空间狭小,进行临床相关手术时应加以重视。     

基于不同FA模板的全脑体素分析方法可靠性的研究

比较基于两种不同FA模板的全脑体素分析(VBA)方法的结果,了解该方法的可靠性,以期为脑白质的功能研究和相关疾病的诊治提供基础信息。选择27例健康成年志愿者,分为青年组(14例)和老年组(13例),行磁共振弥散张量成像扫描。首先使用DTIStudio软件对图像进行自动配准和张量计算,获取部分各向异性(FA)图,然后利用统计参数图(SPM8)软件对FA图进行配准、归一化、平滑等预处理,最后分别基于SPM8软件下产生的专用FA模板和本实验室自主开发的正常中国人FA模板,对两组间的脑白质FA值进行全脑体素分析比较。以纤维束示踪的空间统计学(TBSS)方法和相关文献结果为标准,对以上比较结果进行验证。在基于SPM8产生的专用FA模板下,与青年组对比,老年组的双侧内囊前、后肢,左外囊,左额上回,左枕叶,右放射冠,右大脑脚底,右额中、下回,右小脑中脚的FA值显著下降(P<0.05,簇错误率校正);在基于正常中国人FA模板下,老年组的左内囊后肢,左外囊,左额上回,左颞中回,左枕叶,右放射冠,右内囊前、后肢,右大脑脚底,右额中、下回和胼胝体膝部的FA值相对于青年组显著下降(P<0.05,簇错误率校正);两种模板结果的不一致区域共有4个,即:左内囊前肢、右小脑中脚和左颞中回、胼胝体膝部,前两个区域出现在第一个模板中,后两个区域出现在第二个模板中,根据TBSS方法的激活区结果可得出左内囊前肢、右小脑中脚是假阳性,TBSS方法和相关文献结果支持第二个模板的结论。在采用VBA方法对脑白质进行分析时,基于正常中国人FA模板有助于提高结果的客观性和可靠性。     

The cuprizone model: regional heterogeneity of pathology

The cuprizone model is a model of de- and remyelination secondary to oligodendrocyte death, likely to be mediated by an inhibition of mitochondrial function. The aim of this study was to characterize histopathological changes associated with de/remyelination in grey and white matter at different disease stages in C57Bl/6 mice after per oral administration of cuprizone. Oligodendrocyte loss, astrocytosis and complement activation was detected in areas of demyelination. Demyelination, astrocytosis and complement activation occurred earlier in the cerebral cortex than in the corpus callosum. There was no perivascular lymphocyte infiltration. Microglia- and macrophage activation was observed in the corpus callosum, but not in the cerebral cortex. After cuprizone exposure was stopped, remyelination was extensive in the corpus callosum, but scarce in the cortex. In conclusion, cortical demyelination and oligodendrocyte loss in the cuprizone model may be due to a direct effect on oligodendrocyte mitochondrial function, as it occurs in the absence of microglial activation. The histopathology of de/remyelination in the cuprizone treated mice show regional heterogeneities which suggest differences in the underlying pathophysiology. Cuprizone-induced demyelination is a relevant model for the study of regional heterogeneity of demyelination and lesion pathology in multiple sclerosis.