光学成像观测大鼠局灶性脑缺血的动态过程

采用 550 nm 内源信号光学成像 (optical intrinsic signal imaging , OISI) 监测左侧大脑中动脉栓塞 (middle cerebral artery occlusion , MCAO) 局灶性脑缺血大鼠顶叶皮层 . MCAO 后 4 h 内,观测到一系列自发扩散性抑制 (spreading depression , SD) 波 (10.3±4.6) 次 . 前 2 h 内的 SD 波通常会侵袭整个左侧顶叶皮层,但光信号有明显的区域差异 . 后 2 h 内的 SD 波局限于顶叶皮层中央区域,且传播面积逐次减少;旁侧区域光强基线逐步升高, 4 h 时,反射光强升高 (8.4±1.2) %. 随后 TTC 染色证明上述旁侧区域已经梗死 . 实验表明光学成像为确定缺血半暗带并监测其动态发展提供了一种有效方法 .     

电针对大鼠局灶性脑缺血后脑内Bax,Bcl-2表达的影响

为了探讨 bcl- 2基因家族成员 bax,bcl- 2的表达产物 Bax、 Bcl- 2与电针抗缺血脑损伤的关系。本实验采用改良线拴法制备大鼠大脑中动脉 (MCA )阻塞 -再灌注模型 ,并用 TTC及 HE染色观察缺血及电针后梗塞灶的变化 ,用免疫组织化学方法对大鼠局灶性脑缺血组织内 Bax,Bcl- 2免疫阳性细胞的分布及电针对该分布的影响进行观察。发现 :1.行为生理学观察 :电针组大鼠神经缺损 Bederson综合评分明显低于缺血组综合评分 (P<0 .0 5 ) ;2 .TTC染色表明梗塞灶中心位于尾壳核 ,累及大脑皮层 ;HE染色计算缺血组梗塞灶体积为 74.72± 3.6 7m m3,电针组为 5 2 .6 6± 1.81mm3,两组间有显著性差异 (P<0 .0 1) ;3.大鼠 MCA阻塞 30 m in再灌注 48小时后 ,缺血组及电针组梗塞灶中心 (尾壳核 )偶见 Bax及 Bcl- 2免疫阳性细胞 ;缺血组半影区 Bax阳性细胞数量显著增加 (P<0 .0 1)。 Bcl- 2免疫阳性细胞数反应性上调 (P<0 .0 5 ) ;电针组半影区 Bax的表达与缺血组相比下调 (P<0 .0 5 ) ,但仍高于对照组 (P<0 .0 5 ) ;Bcl- 2的表达与缺血组之间无差异显著性。海马 CA1区神经元 Bax,Bcl- 2的表达在各组间均无显著性差异。结果表明电针有抗缺血脑损伤的效应 ,其分子机制之一可能是通过下调半影区 Bax的表达而相对降低 Bax/Bcl- 2比     

HIF-1α/Sonic Hedgehog信号通路在大鼠胃黏膜病变演化过程中的动态表达

该文探究了HIF-1α/Sonic Hedgehog(Shh)信号通路的动态表达与胃黏膜病变演化过程的关系及其意义.选用72只乳鼠(SD大鼠,8周龄+,雄性)随机分为正常组、模型组,予1-甲基-3-硝基-1-亚硝基脈(N-methyl-N'-nitro-N-nitrosoguanidine,MNNG)建立胃癌前病变模型...     

白藜芦醇对大鼠局灶性脑缺血再灌注的治疗作用

目的:观察白藜芦醇对大鼠局灶性脑缺血再灌注损伤的治疗作用及可能的机制。方法:将SD大鼠随机分为2组:对照组(n=16),白藜芦醇组(n=16)。对照组再灌注即刻腹腔给予0.5 ml生理盐水,白藜芦醇组再灌注即刻腹腔给予20 mg/kg白藜芦醇。再灌注22小时后,进行神经功能学评分、脑梗死容积测定,用分光光度仪测定脑组织溶浆中SOD、MDA和MPO的含量。结果:再灌注22小时后,白藜芦醇治疗组可以改善大鼠神经功能学评分和降低脑梗死面积(P<0.05),同时可以增加脑组织溶浆中SOD的活性,降低MDA和MPO的含量。结论:白藜芦醇通过减轻白细胞的浸润、提高自由基的清除率对大鼠局灶性脑缺血再灌注损伤发挥治疗作用。     

插线法制作大鼠局灶性脑缺血再灌流模型方法的改进

目的 探索插线法制作大鼠局灶性脑缺血再灌流模型方法的改进。方法 在前人制作模型方法基础上进行部分改进,用提线法阻断血流和在颈外动脉上剪小口进行插线。结果 缩短了手术时间,简化了模型制作过程,提高模型成功率。结论 本法复制插线法制作大鼠局灶性脑缺血再灌流模型,省时,操作简便,提高成功率。     

大鼠局灶性脑缺血后扩布性阻抑的发作及电针对其影响

目的：观察Wistar大鼠局灶性脑缺血后扩布性阻抑（SD）的发作情况及缺血后电针的影响。方法：线检法闭塞大鼠大脑中动脉,制备局灶性脑缺血模型。用神经电生理、神经病理等方法检测局灶性脑缺血后3h内SD发作情况及电针“合谷”穴（LI4）对SD的影响。结果：电针可减少局灶性脑缺血时SD的发作。结论：电针减少局灶性脑缺血时SD的发作,可能与电针缩小局灶性脑梗塞体积有关。     

大鼠局灶性脑缺血后KCl诱导皮层扩散性抑制的体光学成像

采用线栓法制备大鼠大脑中动脉栓塞(middle cerebral artery occlusion,MCAO)模型,在额叶皮层用KCl诱导产生皮层扩散性抑制(cortical spreadingdepression,CSD).MCA04 h后,利用550 nm内源信号光学成像(optical intrinsic signalimaging,OISI)监测局灶性脑缺血后大鼠顶-枕叶皮层内源光信号变化.成像1 h内观测到一系列诱导CSD波(14±3次),CSD波局限于顶-枕叶皮层中央区域扩展,以光强的显著下降为特征;而旁侧区域光强无明显改变,不具备CSD波特征,表明CSD波未传播到该区域.随后TIC染色证明上述旁侧区域已经梗死.实验表明:MCAO后4h,皮层区域旁侧部分会梗死;CSD波的0IS变化可用来区分缺血梗死区和外周供血较为完整区域(未梗死区).     

大鼠局灶性脑缺血后KCl诱导皮层扩散性抑制的体光学成像

采用线栓法制备大鼠大脑中动脉栓塞(middlecerebralarteryocclusion,MCAO)模型,在额叶皮层用KCl诱导产生皮层扩散性抑制(corticalspreadingdepression,CSD)。MCAO4h后,利用550nm内源信号光学成像(opticalintrin-sicsignalimaging,OISI)监测局灶性脑缺血后大鼠顶-枕叶皮层内源光信号变化。成像1h内观测到一系列诱导CSD波(14±3次),CSD波局限于顶-枕叶皮层中央区域扩展,以光强的显著下降为特征;而旁侧区域光强无明显改变,不具备CSD波特征,表明CSD波未传播到该区域。随后TTC染色证明上述旁侧区域已经梗死。实验表明:MCAO后4h,皮层区域旁侧部分会梗死;CSD波的OIS变化可用来区分缺血梗死区和外周供血较为完整区域(未梗死区)。     

头针对局灶性脑缺血脑微血管内皮细胞ICAM-1影响的动态观察

目的:在分子水平探讨并阐明脑缺血再灌注脑损伤的炎性机理和针刺对局灶性脑缺血模型脑微血管内皮细胞功能的动态影响。方法:采用大脑中动脉线栓阻塞法建立大鼠局灶性脑缺血模型;用免疫组化SABC法检测脑缺血后治疗1d、3d、5d、10d细胞间粘附分子-1的表达。结果:针刺不同疗程治疗各组大鼠在治疗前后的神经症状行为评定分析有显著性差异(p＜0．05);模型组ICAM-1脑缺血后ID即出现表达,5D达到表达高峰,各个时间点相比具有显著的统计学意义(P＜0．01)。结论:头针对脑缺血状态下微血管内皮细胞功能的全方位和多层面良性调节机制,并且这种良性机制随着干预时间的选择(早期/6 d)和疗程的适度延长(5天以上),具有明显的累加蓄积效应。     

甘草查尔酮A对局灶性脑缺血再灌注小鼠Nrf2/HO-1信号通路和神经炎症反应的影响

目的:探讨甘草查尔酮A对局灶性脑缺血再灌注小鼠Nrf2/HO-1信号通路和神经炎症反应的影响。方法:体重23~25 g的雄性C57BL/6小鼠总计96只,随机分为4组(n=24):假手术对照组(Sham组)、脑缺血再灌注组(MCAO组)、溶剂组(Vehicle组)、甘草查尔酮A组(LA组)。采用大脑中动脉栓塞(MCAO)模型致大鼠脑缺血损伤。72 h后行神经功能学评分,2,3,5-三苯基氯化铵(TTC)染色检测脑梗死体积,Western blot法检测脑Nrf2、HO-1、TNF-α、IL-6蛋白表达水平,TUNEL染色法检测凋亡细胞数。结果:与Sham组比较,MCAO组和Vehicle组小鼠神经功能评分明显降低(P0.05),脑梗死体积显著增加(P0.05),而核蛋白Nrf2和胞浆蛋白HO-1蛋白表达水平较低(P0.05),炎症因子IL-6和TNF-α表达水平明显增加(P0.05),脑实质炎性细胞浸润显著增多(P0.05);与MCAO组和Vehicle组比较,LA组小鼠神经功能评分明显增加(P0.05),脑梗死体积显著减少(P0.05),而核蛋白Nrf2和胞浆蛋白HO-1蛋白表达水平更高(P0.05),炎症因子IL-6和TNF-α表达水平明显减少(P0.05),脑实质炎性细胞浸润明显减少(P0.05)。结论:甘草查尔酮A可缓解脑缺血再灌注损伤后出现的神经炎症反应及细胞凋亡,进而减轻神经功能障碍和脑梗死体积,其机制可能与激活Nrf2/HO-1信号通路相关。     

Comparison of Cortical and White Matter Traumatic Brain Injury Models Reveals Differential Effects in the Subventricular Zone and Divergent Sonic Hedgehog Signaling Pathways in Neuroblasts and Oligodendrocyte Progenitors

The regenerative capacity of the central nervous system must be optimized to promote repair following traumatic brain injury (TBI) and may differ with the site and form of damage. Sonic hedgehog (Shh) maintains neural stem cells and promotes oligodendrogenesis. We examined whether Shh signaling contributes to neuroblast (doublecortin) or oligodendrocyte progenitor (neural/glial antigen 2 [NG2]) responses in two distinct TBI models. Shh-responsive cells were heritably labeled in vivo using Gli1-CreER^T2;R26-YFP bitransgenic mice with tamoxifen administration on Days 2 and 3 post-TBI. Injury to the cerebral cortex was produced with mild controlled cortical impact. Yellow fluorescent protein (YFP) cells decreased in cortical lesions. Total YFP cells increased in the subventricular zone (SVZ), indicating Shh pathway activation in SVZ cells, including doublecortin-labeled neuroblasts. The alternate TBI model produced traumatic axonal injury in the corpus callosum. YFP cells decreased within the SVZ and were rarely double labeled as NG2 progenitors. NG2 progenitors increased in the cortex, with a similar pattern in the corpus callosum. To further test the potential of NG2 progenitors to respond through Shh signaling, Smoothened agonist was microinjected into the corpus callosum to activate Shh signaling. YFP cells and NG2 progenitors increased in the SVZ but were not double labeled. This result indicates that either direct Smoothened activation in NG2 progenitors does not signal through Gli1 or that Smoothened agonist acts indirectly to increase NG2 progenitors. Therefore, in all conditions, neuroblasts exhibited differential Shh pathway utilization compared with oligodendrocyte progenitors. Notably, cortical versus white matter damage from TBI produced opposite responses of Shh-activated cells within the SVZ.     

Sonic hedgehog在二乙基亚硝胺诱发大鼠肝癌发生过程中的表达及意义

观察肝脏组织中Sonic hedgehog(Shh)的表达情况,探讨其在肝癌发生发展过程中的作用.用二乙基亚硝胺(diethylnitrosamine,DEN)制备诱发型肝癌模型,利用光镜技术观察诱癌过程中肝组织的形态学改变,采用免疫组织化学二步法和RT-PCR技术检测Shh蛋白和mRNA的表达.根据形态学观察将诱癌过程分为正常对照组、肝损伤组、肝增生-硬化组和肝癌变组.Shh蛋白阳性表达的细胞主要分布在小叶间胆管上皮、肝细胞增生结节、癌周组织和癌结节中,在对照组、肝损伤期、肝增生-硬化期和肝癌变期的阳性表达率分别是6.67%、30.00%、52.94%和78.57%(χ2=17.49,P<0.05).Shh mRNA表达率随着肝癌的发生发展有逐渐增高的趋势(χ2=13.35,P<0.05),对Shh mRNA表达阳性的电泳条带进行图像分析结果显示Shh mRNA表达量随着肝癌的发生发展逐渐增高(F=110.26,P<0.05).Ptch mRNA表达率随着肝癌的发生发展有逐渐增高的趋势(χ2=19.83,P<0.05),对Ptch mRNA表达阳性的电泳条带进行图像分析结果显示Ptch mRNA表达量随着肝癌的发生发展逐渐增高(F=68.28,P<0.05).实验结果提示,Shh在肝癌发生发展过程中出现了异常活动,导致Shh信号通路激活并作用于肝的细胞,参与了诱导肝癌的发生发展.     

IGF-1对缺血性脑损伤大鼠脑内神经发生的影响

目的:建立大鼠单侧局灶脑缺血模型,观察胰岛素样生长因子-1(IGF-1)对局灶脑缺血后的鼠脑神经发生及增殖后细胞生存的影响.方法:用健康雄性SD大鼠建立大脑中动脉阻塞(MCAO)模型,随机分成假手术组,缺血对照组和IGF-1治疗组.各组再按不同的治疗时间分为7d、14d、28d、42d组.免疫组化法观察BrdU、PSA-NCAM的变化,免疫双标法观察BrdU/PSA-NCAM、BrdU/MAP2和BrdU/GFAP的共同表达变化.结果:BrdU标记细胞和PSA-NCAM标记细胞计数均在缺血后第7d最多,分别是缺血对照组的4.0倍和1.8倍,是假手术组的9.9倍和5.4倍.BrdU和PSA-NCAM双标细胞在缺血发生后双侧SVZ和DG区可以检测到,于第7d计数最多,之后逐渐降低;而BrdU和MAP2以及BrdU和GFAP双标细胞却从第14d开始逐渐增多,直到第42d.随着BrdU/PSA-NCAM双标阳性表达的逐渐降低,BrdU/MAP2双标阳性表达逐渐增高,呈现此消彼涨的变化.结论:IGF-1侧脑室注射后,在早期(7d内)诱导了缺血性脑损伤后神经细胞的增殖;在中期(7d-14d)诱导了新生细胞的迁移;在后期(14d后)伴随着迁移的进行新生细胞逐渐发生了分化.     

Pre- and Posttreatment With Edaravone Protects CA1 Hippocampus and Enhances Neurogenesis in the Subgranular Zone of Dentate Gyrus After Transient Global Cerebral Ischemia in Rats

Edaravone is clinically used for treatment of patients with acute cerebral infarction. However, the effect of double application of edaravone on neurogenesis in the hippocampus following ischemia remains unknown. In the present study, we explored whether pre- and posttreatment of edaravone had any effect on neural stem/progenitor cells (NSPCs) in the subgranular zone of hippocampus in a rat model of transient global cerebral ischemia and elucidated the potential mechanism of its effects. Male Sprague-Dawley rats were divided into three groups: sham-operated (n = 15), control (n = 15), and edaravone-treated (n = 15) groups. Newly generated cells were labeled by 5-bromo-2-deoxyuridine. Immunohistochemistry was used to detect neurogenesis. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling was used to detect cell apoptosis. Reactive oxygen species (ROS) were detected by 2,7-dichlorofluorescien diacetate assay in NSPCs in vitro. Hypoxia-inducible factor-1α (HIF-1α) and cleaved caspase-3 proteins were quantified by western blot analysis. Treatment with edaravone significantly increased the number of NSPCs and newly generated neurons in the subgranular zone (p < .05). Treatment with edaravone also decreased apoptosis of NSPCs (p < .01). Furthermore, treatment with edaravone significantly decreased ROS generation and inhibited HIF-1α and cleaved caspase-3 protein expressions. These findings indicate that pre- and posttreatment with edaravone enhances neurogenesis by protecting NSPCs from apoptosis in the hippocampus, which is probably mediated by decreasing ROS generation and inhibiting protein expressions of HIF-1α and cleaved caspase-3 after cerebral ischemia.     

Ephrin-B2促进大鼠局灶脑缺血再灌注后VEGF表达及血管新生

目的:探讨Ephrin-B2对大鼠脑缺血再灌注后脑组织中血管新生的调节作用及其可能的机制。方法:雄性SD大鼠随机分为正常组及、缺血再灌注组及Ephrin-B2干预组,后两组再分为4天、7天、14天、28天亚组;线栓法制备局灶性大脑中动脉缺血再灌注模型;改良神经功能评分(modified neurological severity scores mNSS)评分法对各时间点模型进行评分;Western blot及荧光定量PCR检测缺血脑组织中血管内皮生长因子(Vascular Endothelial Growth Factor VEGF)的表达;以免疫荧光双标法定位VEGF表达的细胞类型;以CD31+BrdU计数缺血半暗带中新生微血管密度(microvessel densityMVD)。结果:Ephrin-B2干预组与缺血再灌注组各时间点亚组比较,新生微血管密度测定计数较缺血再灌注组均显著增加(P0.05),神经功能评分均显著降低(P0.05),VEGF mRNA水平及蛋白表达水平均显著增加(P0.05),VEGF主要表达于CD31阳性的血管内皮细胞。结论:Ephrin-B2通过上调VEGF的表达促进脑缺血再灌注后缺血半暗带血管新生,从而促进神经功能缺失的修复。     

Reduction of Mitochondrial Electron Transport Complex Activity Is Restricted to the Ischemic Focus After Transient Focal Cerebral Ischemia in Rats: A Histochemical Volumetric Analysis

Using histochemical methods offering high topographical resolution for evaluation of changes in the ischemic focus and the penumbra, the mitochondrial electron transport chain (ETC) complexes I, II, and IV were examined in rats subjected to 2 h of proximal occlusion of the middle cerebral artery (MCAO) followed by no reperfusion, 1 h reperfusion, 4 h reperfusion, or 4 h reperfusion plus treatment with the free radical scavenger -PBN. Serial brain cryosections were histochemically stained to visualize activity of complexes I, II, and IV, and the volumes of tissue with reduced activity in the ipsilateral cortex and caudate putamen were measured by densitometric image analysis. Reductions in complex I, II, and IV activity were restricted to areas in the ischemic foci in cortex and caudate putamen, which microscopically displayed signs of early morphological damage. In cortex, the tissue volume with reduced activity did not change significantly during reperfusion but progressively increased in the caudate putamen, possibly reflecting a faster maturation of morphological damage in this region. Treatment with -PBN did not affect the observed reductions in activities. We deduce that inhibition of mitochondrial ETC complex activity does not play a critical role for recruitment of the penumbra in the infarction process.     

大鼠局灶性脑缺血模型的有效制备

目的比较三种不同手术方法制作大鼠永久性脑缺血模型的效果,包括死亡率、神经功能评分、脑梗死体积、手术效率。方法将采用不同手术方法制备脑缺血模型的大鼠随机分为三组。1组在术中分别结扎颈总动脉（CCA）、颈外动脉（ECA）、枕动脉、翼腭动脉,并且用动脉夹对颈内动脉（ICA）进行临时夹闭;2组在术中分别结扎颈总动脉、颈外动脉,暴露枕动脉和翼腭动脉但不结扎,用丝线悬挂颈内动脉而不是用动脉夹夹闭,线栓在显微镜直视下插入颈内动脉越过翼腭动脉起始点至大脑中动脉分叉处;3组只暴露颈总动脉、颈外动脉和颈内动脉,结扎颈总动脉、颈外动脉,丝线悬挂颈内动脉,显微镜下将线栓盲插至颈内动脉大脑中动脉分叉处。分别检测三组模型的死亡率、神经功能评分、梗死体积、手术时间。结果第3组制作动物模型的方法所花费时间平均为17.5 min,死亡率较低,神经功能评分及梗死体积稳定。结论采用第3组手术方法可以缩短手术时间,提高手术效率,能够高效地制作出更加稳定的可用于临床实验的大鼠脑缺血模型。