Fluoro-Jade C揭示匹罗卡品模型中梨状皮质神经元变性

目的应用Fluoro-Jade C(FJC)染色方法在小鼠匹罗卡品癫痫模型中检测梨状皮质结构中神经元的变性情况,以了解梨状皮质结构在慢性颞叶癫痫发生中的病理变化和癫痫反复发作的神经基础。方法雄性昆明小鼠10只(对照组5只,匹罗卡品处理组5只)。处理组在癫痫持续状态后3d处死处理组小鼠。在梨状皮质水平切制冠状切片,行FJC染色,在荧光显微镜下观察FJC阳性细胞的形态和在梨状皮质中的整体分布情况。结果在处理组,FJC染色的脑切片上可以很清楚地看到呈亮黄绿色荧光的FJC阳性细胞,呈神经元形态,胞体和突起均清晰显示。在梨状皮质和梨状内核内出现大量FJC阳性细胞,而对照组未见。结论在小鼠匹罗卡品癫痫模型中运用FJC染色技术显示梨状皮质内发生了大量神经元变性,此研究有利于更好地理解颞叶癫痫中中枢神经系统所发生的长期病理变化和自发反复发作的癫痫机制。     

应用Fluoro-Jade C评价匹罗卡品模型丘脑神经变性

目的 应用Fluoro-Jade C(FJC)染色方法 观察小鼠匹罗卡品癫(癎)模型丘脑神经元变性情况,以了解丘脑结构在慢性颞叶癫痫发生中的病理变化和癫(癎)反复发作的神经学基础.方法 以盐酸匹罗卡品腹腔注射(220 mg/kg)制备小鼠癫痼持续状态模型.脑组织切片经FJC染色后.荧光显微镜下观察FJC阳性细胞形态和在丘脑的整体分布情况.结果 匹罗卡品模型组小鼠FJC阳性细胞呈神经元形态,丘脑结构损害呈连续性.功能不同的丘脑核其细胞损害程度有所不同.结论 采用FJC染色技术观察匹罗卡品癫(癎)持续状态小鼠模型丘脑神经元变性情况,有利于更好地理解颞叶癫(癎)的中枢神经系统长期病理变化和自发性反复发作机制.     

单剂量匹罗卡品诱导小鼠癫痫及其海马神经损伤的研究

目的 探索不同剂量匹罗卡品单次腹腔注射对诱发小鼠癫痫及对海马损伤的影响,为癫痫建模提供参考。方法将100只健康的C57BL/6小鼠随机分为正常对照组、3个不同剂量匹罗卡品(250 mg/kg、290 mg/kg、350 mg/kg)腹腔注射组。比较3组的建模成功率、死亡率,通过免疫组化染色观察神经元和胶质细胞的数量变化,分析海马区组织的病变情况。结果 匹罗卡品250 mg/kg组小鼠的Racine评分4级以上发作率为12%,无死亡; 290 mg/kg组小鼠的4级以上发作率为70%,死亡率为32%; 350 mg/kg组小鼠的4级以上发作率为86%,死亡率为56%。免疫组化染色结果显示:与正常对照组相比,3个不同剂量匹罗卡品组小鼠诱发癫痫后,神经元数量均显著减少,小胶质细胞和星形胶质细胞数量均显著增加;但250 mg/kg组小鼠的活化小胶质细胞数量无显著变化,而其他两组显著增多。结论 匹罗卡品290 mg/kg单次注射诱发小鼠癫痫模型的成功率较高、死亡率较低,且海马区损伤明显,可以作为癫痫小鼠建模的参考方法。     

经鼻给予TGFβ1对癫痫持续状态大鼠海马神经元的保护作用

目的探讨经鼻腔给予TGFβ1(transforming growth factor beta1,TGFβ1)对氯化锂-匹罗卡品所致癫痫持续状态(status epilepticus,SE)大鼠海马神经元的保护作用及其潜在的机制。方法健康雄性SD大鼠60只,随机分为转化生长因子(TGF)组、匹罗卡品(Pilo)组和正常对照组(control)。建立氯化锂-匹罗卡品癫痫持续状态模型。应用TUNEL染色、Fluoro-Jade B(FJB)荧光染色法分别观察各组大鼠海马神经元的原位凋亡及变性死亡情况。采用免疫组化方法检测凋亡相关基因caspase-3的蛋白表达。结果 SE后24h、48h、72h,TGF组大鼠海马FJB、TUNEL、caspase-3阳性细胞均较Pilo组显著减少(P<0.05);72h最为明显(P<0.01)。结论经鼻(IN)给予TGFβ1可以显著抑制或减轻癫痫持续状态大鼠海马神经元的变性与凋亡,从而发挥神经保护作用。其潜在的神经保护机制可能涉及下调caspase-3蛋白表达。     

粒细胞集落刺激因子对癫痫模型小鼠神经元及神经炎症的影响

目的探讨粒细胞集落刺激因子(granulocyte colony-stimulating factor,G-CSF)在癫痫小鼠海马中的表达及其对神经元和神经炎症的影响。方法匹罗卡品诱导小鼠TLE模型。小鼠分成对照组(n=8),匹罗卡品组(P组,n=8),经粒细胞集落刺激因子干预的匹罗卡品组(P+G组, n=9)。采用免疫荧光法观察G-CSF在脑组织中的表达;Western Blot检测GFAP、IL-1β、IL-6、G-CSF的表达;尼氏染色观察神经元的变化。结果 G-CSF在星形胶质细胞中表达;Western Blot检测发现P组G-CSF的表达高于对照组,低于P+G组;P+G组GFAP、IL-1β、IL-6较P组明显减少;尼氏染色示:P组与对照组比较神经元明显减少;P+G组神经元较P组增多,且形态较P组规则。结论小鼠癫痫后海马中G-CSF表达升高,注射G-CSF可能能够抑制癫痫小鼠海马中星形胶质细胞的异常增生,改善神经元形态和数量,减少神经炎症反应,刺激海马区分泌G-CSF。     

匹罗卡品致痫大鼠海马calpain活性变化和其对神经元死亡的影响

目的探讨在匹罗卡品致痫的癫痫持续状态（SE）大鼠模型中,钙蛋白酶在大鼠海马组织中的活性,及钙蛋白酶对神经元坏死、凋亡产生的影响。方法雄性成年wistar大鼠,应用匹罗卡品致痫产生SE后60min后终止发作,24h后取材,行HE染色及tunel染色,观察海马神经元的坏死及凋亡情况,以及western blot检测钙蛋白酶1（μ-calpain）的活性。结果癫痫持续状态后24h,海马组织HE染色神经元数量减少,tunel阳性细胞数增加,钙蛋白酶1出现76ku条带。结论大鼠癫痫持续状态后24h,钙蛋白酶1在海马组织神经元活性增加,海马神经元出现坏死及凋亡。钙蛋白酶1与神经元的死亡存在着正相关。     

氯化锂-匹罗卡品致痫幼鼠脑内c-jun和c-fos蛋白的表达

目的 探讨幼鼠癫痫持续状态(SE)后脑内c-jun和c-fos蛋白的表达。方法 采用氯化锂-匹罗卡品腹腔注射制成幼鼠SE模型。应用免疫组化及常规病理检查方法观察c-jun和c-fos蛋白的表达。结果 注射匹罗卡品1h后在海马结构和大脑皮质的大部分区域出现少量的c-jun和c-fos免疫反应阳性细胞，3～6h强烈表达，并达到高峰，24h后明显减弱，72h近乎正常对照水平。地西泮干预组幼鼠脑内有少量的c-jun和c-fos免疫反应阳性细胞，略多于生理盐水对照组。海马结构区的c-jun和c-fos免疫反应阳性细胞明显高于皮质区。SE组幼鼠的CA1、CA3和齿状回区可见到许多神经元发生变性和坏死。结论 c-jun和c-fos蛋白表达及其表达程度与SE后脑损伤的部位和分布有关；地西泮有对抗匹罗卡品致病作用，可能对脑组织有保护作用。     

氯化锂-匹罗卡品致痫幼鼠海马结构损伤的形态学及苔藓纤维发芽研究

目的 观察幼鼠致痫后海马的组织病理学改变。方法 采用氯化锂－匹罗卡品腹腔注射制成幼鼠癫痫持续状态模型，应用常规病理及电镜观察海马结构的形态学改变，同时应用Timm组织化学染色方法进行苔藓纤维发芽的研究。结果 海马区神经元可见变性、坏死改变，以CA1区、CA3区为重。Timm染色见齿状回内分子层和CA3区下锥体层苔藓纤维发芽增加。结论 （1）氯化锂－匹罗卡品诱导的幼鼠癫痫持续状态可造成海马区神经元损伤；（2）幼鼠癫痫持续状态后海马CA1、CA3区神经元损伤较重；（3）幼鼠癫痫持续状态后可致苔藓纤维发增加。     

建立杏仁核电刺激慢点燃和匹罗卡品化学点燃耐药性颞叶癫痫模型并对比癫痫发作和海马超微结构的变化

目的用两种方法建立颞叶耐药癫痫模型,探讨哪种方法更适合建立多药耐药颞叶癫痫模型。方法选用SD大鼠130只,10只作为正常组,120只分别制作杏仁核和匹罗卡品模型,模型成功后用抗癫痫药苯巴比妥和苯妥英钠或卡马西平进行筛选,分别选择10只杏仁核模型和匹罗卡品模型比较两种方法建立的模型癫痫发作持续时间、发作频率、发作级别、脑电图及电镜下超微结构的变化。结果成功制作杏仁核模型31只,匹罗卡品模型29只,匹罗卡品模型癫痫发作频率(2. 09±0. 044)高于杏仁核组(1. 01±0. 037),持续时间(61. 37±4. 22)长于杏仁核组(43. 16±5. 91),而癫痫发作的级别无明显差异;经过耐药性癫痫模型的筛选,选出杏仁核耐药模型8只,匹罗卡品耐药模型12只。匹罗卡品模型与杏仁核模型相比脑电频率更高,波幅增宽,超微结构的损伤更严重。结论匹罗卡品模型自发性率高,耐药率高,脑电变化明显,超微结构损伤重,更适合耐药性癫痫机制的研究。     

IL-1β通过NF-κB促进大鼠内侧颞叶癫痫慢性进展

目的探讨白介素1-beta(IL-1β)在大鼠内侧颞叶癫痫(MTLE)模型病情进展中的作用,并探讨其与核因子-κB(NF-κB)的作用关系。方法利用匹罗卡品诱导SD鼠发作癫痫制成MTLE模型,并于制模成功后0.5h侧脑室注射IL-1β,于慢性期(8w),利用行为学观察、脑电图检测观察模型鼠自发癫痫的情况,利用Nissl染色和Timm染色观察模型鼠海马神经元脱失和苔藓纤维增生情况;利用凝胶迁移电泳(EMSA)和免疫组化(IHC)观察海马内NF-κB和NF-κB p65的表达。结果 IL-1β可以提高匹罗卡品诱导的MTLE模型鼠慢性期自发癫痫的发生率,且加重海马内神经元脱失和苔藓样纤维增生,并且NF-κB表达增加,与对照组和单纯匹罗卡品诱导组比较均有统计学差异(P<0.05)。结论 IL-1β通过NF-κB促进匹罗卡品诱导的MTLE模型鼠癫痫慢性自发发作,是导致MTLE进展的机制之一。     

小鼠真皮多能干细胞在缺血性损伤脑组织移植后的分布与分化

目的探讨小鼠真皮多能干细胞(SKP)经股静脉移植后在缺血性损伤脑组织中的分布及分化情况。方法分离培养绿色荧光蛋白转基因小鼠(C57BL/6-gfp)SKP,随机选取5只同基因型小鼠采用线栓法制作局灶性大脑中动脉栓塞(MCAO)模型,缺血2h后行再灌注,再灌注24h后将C57BL/6-gfp来源的SKP经小鼠股静脉输入动物模型体内,植入后第7天处死小鼠,作冷冻切片,采用免疫组织荧光染色法,检测SKP在脑缺血小鼠体内的分布及分化情况。结果移植SKP7d后,MCAO小鼠脑组织冷冻切片在荧光显微镜下可见移植的SKP主要分布在缺血灶周围,且这些细胞表达胶质纤维酸性蛋白(GFAP)和神经元特异性烯醇化酶(NSE)。结论经股静脉移植的SKP主要分布在MCAO模型鼠脑缺血损伤区周围,并可向神经细胞分化。     

实验性自身免疫性脑脊髓炎小鼠神经损害与脑组织中丝裂原活化蛋白激酶表达的关系

目的观察实验性自身免疫性脑脊髓炎(EAE)模型小鼠脑组织中丝裂原活化蛋白激酶(MAPKs)表达变化及其与神经损害的关系。方法 C57BL/6小鼠随机分为:EAE组(n=12),采用髓鞘少突胶质细胞糖蛋白35-55多肽(MOG35-55)制备成抗原乳剂免疫小鼠;对照组(n=10),用生理盐水处理小鼠。每日观察两组小鼠的行为学变化,并进行神经功能障碍评分。于高峰期处死小鼠,冰冻处理脑与脊髓,行苏木精-伊红染色观察脊髓组织的炎症细胞浸润,LFB染色观察脊髓组织的髓鞘脱失,蛋白印迹法检测小鼠脑组织中MAPKs表达。分析EAE小鼠神经功能障碍改变与中枢神经组织MAPKs表达量的相关性。结果 EAE组与对照组比较:日均神经行为学评分增加(P0.01);脊髓炎症细胞浸润增多(P0.001),髓鞘脱失增多(P0.001)。P-ERK(42)、P-ERK(44)、P-JNK(54)表达量均增多(P0.01、P0.05、P0.05)。神经功能障碍与P-ERK(42)、P-ERK(44)、P-JNK(54)表达呈正相关。结论 EAE高峰期神经损伤程度与中枢神经组织中的P-ERK(42)、P-ERK(44)、P-JNK(54)表达增加相平行,提示MOG35-55诱导的EAE中枢神经损伤可能与MAPKs所激活的信号通路有关。     

帕金森小鼠多巴胺能神经元轴突变性研究

目的建立1-甲基-4-苯基-1,2,3,6-四氢吡啶(MPTP)诱导的大龄(32～36 w)小鼠帕金森病慢性模型,探讨其多巴胺能神经元轴突变性在帕金森病发病机制中的作用。方法应用免疫组织化学染色、Fluoro-Jade C染色等方法,观察MPTP诱导的小鼠黑质多巴胺能神经元轴突变性与胞体凋亡的时效性关系。结果慢性MPTP腹腔注射大龄小鼠可诱导产生典型且稳定的帕金森病症状,并可引起黑质-纹状体多巴胺能神经元的凋亡与轴突变性,但轴突变性在发生时间上早于细胞凋亡。结论轴突变性在帕金森病发病机制中起着十分重要的作用,帕金森病可能与神经元-轴突-神经胶质细胞网络损伤密切相关。     

Pre-embedding immunogold labeling of TUNEL stain enables evaluation of DNA strand breaks and ultrastructural alterations in individual cells of neuronal tissue

In the brain apoptosis may occur as a physiological phenomenon during periods of programmed cell death as well as under pathological conditions such as ischemia, trauma, tumor, and degenerative diseases. While the definition of apoptotic cell death was originally based on ultrastructural alterations, the detection of DNA double-strand breaks has become an important feature in studies of apoptosis. Currently, the terminal transferase-mediated dUTP nick-end labeling (TUNEL) procedure is widely used for detection of apoptotic cell death. However, there is a growing body of evidence to suggest that the TUNEL staining does not label apoptotic alterations exclusively. Therefore, a new staining procedure was developed combining TUNEL methodology with pre-embedding nanogold labeling to detect DNA double-strand breaks in individual cells by electron microscopy and assess the accompanying ultrastructural alterations. In vitro DNAse-treated vibratome sections (thickness, 20 micro m) from normal adult rat brains were used to develop the staining procedure consisting of the following steps: (i) TUNEL staining of free-floating vibratome sections using fluorescein isothiocyanate (FITC)-labeled UTP, (ii) conversion of the fluorescence signal into an electron-dense signal using an anti-FITC antibody coupled with ultrasmall (diameter, 0.8 nm) gold particles followed by silver enhancement, and (iii) osmification, embedding in Spurr resin and cutting of ultrathin sections. Early postnatal brain tissue was used to study physiologically occurring apoptotic cell death. Under these conditions different patterns of gold staining were observed probably representing different states of cellular decay along the apoptotic avenue. Severe focal brain ischemia was studied as a pathological situation in which intense TUNEL staining occurs. Under these conditions TUNEL labeling of cells was regularly observed in conjunction with ultrastructural alterations indicative of necrosis. These results suggest that under pathological conditions apoptosis and necrosis are not mutually exclusive mechanisms but rather may occur concurrently along a continuum in which cell death occurs.     

Comparison of labeling methods and time course of traumatic brain injury-induced cell death in mice

BACKGROUND:Various molecular mechanisms of cell death following traumatic brain injury have been previously described.However,the time course of cell death remains unclear.TUNEL and Fluoro-Jade B labeling have been widely used to label apoptotic cells and neuronal degeneration.Propidium iodide (PI) functions as a biomarker of cell death in vivo.OBJECTIVE:To explore the role of PI labeling compared to TUNEL and Fluoro-Jade B staining for detecting neural cell death,and to observe time course of traumatic brain injury-induced cell death in mice.DESIGN,TIME AND SETTING:A randomized,controlled,animal experiment was performed at the Laboratory of Aging and Nervous Diseases,Soochow University from September 2007 to December 2008.MATERIALS:PI (B1221) was purchased from Sigma,USA.TUNEL kit was purchased from Roche Molecular Biochemicals,USA.Fluoro-Jade B was purchased from Chemicon,USA.METHODS:A total of 70 healthy,male,Kunming mice were randomly assigned to sham-surgery (n = 5) and model (n = 65) groups.Traumatic brain injury was established using the controlled cortical impact method.PI was intraperitoneally injected at 1 hour prior to animal sacrifice.MAIN OUTCOME MEASURES:TUNEL,Fluoro-Jade B,and Pl-positive cells were quantified using a double-labeling method to determine the time course of traumatic brain injury-induced cell death.RESULTS:PI labeled cells in an earlier phase of cell death than TUNEL and Fluoro-Jade B labeling.Pl-positive cells were observed immediately following injury,and the numbers rapidly increased in injured brain areas at 1 hour,peaked at 24-48 hours,and subsequently decreased at 3-21 days post-injury.TUNEL-labeled cells were significantly increased at 12 hours,while Fluoro-Jade B-labeled cells were increased at 6 hours after injury,with cells still visible at 6-48 hours post-injury.Moreover,a greater number of Pl-positive cells were observed compared to TUNEL- and Fluoro-Jade B-labeled cells.CONCLUSION:PI labeling is more sensitive and reliable than TUNEL and Fluoro-Jade B staining for detecting cell death following traumatic brain injury.Moreover,PI labeling can function as a reliable marker to estimate the entire time course of cell death.     

Loss of NeuN immunoreactivity after cerebral ischemia does not indicate neuronal cell loss: a cautionary note

NeuN immunoreactivity is used as a specific marker for neurons. The number of NeuN-positive cells decreases under pathological conditions. This finding is usually considered as an evidence of neuronal loss. However, decrease in NeuN labeling may also be caused by depletion of the protein or loss of its antigenicity. Hence, we have investigated the morphological features of neurons that lost NeuN immunoreactivity and the NeuN protein levels in mouse brain after cerebral ischemia. The number of NeuN-labeled cells was decreased 6 h after a mild ischemic insult (30 min middle cerebral artery occlusion) in penumbral and core regions. Hematoxylin and eosin (H&E) staining of adjacent sections showed that neurons in the penumbra were not disintegrated but displayed early ischemic changes. The nuclear NeuN staining was dramatically reduced or lost in some neurons. However, Hoechst 33258 staining of the same sections revealed that these nuclei were preserved with an intact membrane. Labeling of neurons that had lost NeuN-positivity with antibodies against caspase-3-p20, which is constitutively not present but emerges in neurons after ischemia, disclosed that these neurons still preserved their integrity. Moreover, Western blots showed that NeuN protein levels were not decreased, suggesting that reduced NeuN antigenicity accounted for loss of immunoreactivity in this mild brain injury model. Supporting this idea, NeuN labeling was partially restored after antigenic retrieval. In conclusion, since NeuN immunoreactivity readily decreases after metabolic perturbations, reduced NeuN labeling should not be taken as an indicator of neuronal loss and, quantitative analysis based on NeuN-positivity should be used cautiously after central nervous system (CNS) injury.     

EAAT2过表达对匹鲁卡品诱导小鼠癫痫持续状态模型的保护作用

目的 研究兴奋性氨基酸转运体2(EAAT2)过表达对癫痫发作及SE诱导的海马神经元死亡的作用.方法 实验采用野生型或者EAAT2转基因FVB/N小鼠,腹腔注射匹鲁卡品诱导癫痫持续状态(SE).SE后3 d,取脑、固定、切片,进行EAAT2、生长抑素的免疫组化染色以及甲酚紫染色,分别对海马CA1和齿状回门区阳性神经元进行计数.结果 与野生型动物相比,EAAT2在转基因小鼠海马中表达显著增加.野生型小鼠达到SE或者死亡所需的总匹鲁卡品剂量为344±40.3mg/kg,,而EAAT2转基因小鼠达到同等效应所需剂量为657±119.9 mg/kg,显著高于野生型所用剂量(P＜0.05).SE后3 d,野生型小鼠海马CA1区锥体细胞层神经元相对数量为0.56,而转基因动物中为0.9,显著高于野生型动物(P＜0.05).同时,野生型和转基因小鼠癫痫后齿状回门区中间神经元相对数量分别为0.11和0.67,转基因组数量显著高于野生型组(P＜0.05).野生型小鼠癫痫后齿状回门区生长抑素阳性神经元数量为0,但是,在EAAT2转基因小鼠,数量为0.4,显著高于野生型(P＜0.05).结论 EAAT2过表达对SE产生及其诱导的神经元死亡具有显著保护作用.过表达的EAAT2可能通过加强细胞外谷氨酸转运而调控其兴奋毒性.     

氢气盐水治疗迟发性脑血管痉挛实验研究

目的研究饱和氢气盐水对脑血管痉挛其及缺血性脑损害的治疗作用。方法 70只新西兰兔随机分为3组,分别为假手术组(n=10)、生理盐水组(n=30)和氢水治疗组(n=30)。于建模后第3 d、第5 d和第7 d处死动物,脑组织切片后行苏木精-伊红(HE)染色及末端脱氧核苷酸转移酶介导的生物素脱氧尿嘧啶核苷酸缺口末端标记法(TUNEL)染色,观察基底动脉直径及海马神经元凋亡情况。结果氢水治疗组与生理盐水组比较,仅在第5 d氢气治疗可明显减少海马神经元的凋亡(P=0.039),其他各组数据均无统计学差异。结论饱和氢气盐水注射不能显著改善蛛网膜下腔出血后的血管痉挛,但能减轻痉挛高峰期的缺血性脑损害。