神经发生对小鼠学习记忆能力的影响

本研究探讨神经发生对学习记忆能力的影响。选择健康成年昆明小鼠随机分7组,分别为生理盐水对照组,酸性成纤维细胞生长因子(aFGF)高、中、低剂量组,甲氨喋呤(MTX)高、中、低剂量组。使用脑立体定位仪行侧脑室埋管手术及侧脑室微量注射。用Morris水迷宫训练测试其空间学习与记忆能力;腹腔注射5-溴脱氧尿苷(BrdU)后通过免疫组织化学方法来显示Br-dU阳性细胞。结果表明,aFGF各剂量组学习记忆能力均强于生理盐水对照组;MTX高剂量组学习记忆能力显著低于生理盐水对照组。免疫组织化学结果显示aFGF各剂量组齿状回内BrdU阳性细胞数目显著高于对照组;而MTX高剂量组齿状回BrdU阳性细胞较之显著减少。结果提示,aFGF和MTX可能通过促进或抑制齿状回的神经发生,从而影响小鼠的学习与记忆能力。     

~(60)Co-γ射线照射对小鼠SVZ神经干细胞增殖的影响

目的:探讨60Co-γ射线照射对成体小鼠侧脑室室管膜下区(SVZ)神经干细胞增殖的影响。方法:28只昆明小鼠随机分成4组,每组7只,分别以0 Gy、5 Gy(小剂量)、15 Gy(中剂量)、30 Gy(大剂量)剂量进行照射,于照射后1周观察侧脑室室管膜下区(SVZ)的5-溴脱氧核苷尿嘧啶(BrdU)阳性细胞形态和数目。结果:照射后1周,各照射组SVZ的BrdU阳性细胞形态与对照组无差别,呈圆形、椭圆形以及梭形等;15 Gy、30 Gy照射组SVZ的BrdU阳性细胞数明显降低(P<0.01),5 Gy照射组SVZ的BrdU阳性细胞数无差别(P>0.05)。结论:大中剂量60Co-γ照射会抑制SVZ神经干细胞的增殖分裂能力。     

Ⅰ型糖尿病脑病大鼠学习记忆及侧脑室室管膜下区神经发生的变化

目的观察Ⅰ型糖尿病脑病对学习记忆及侧脑室室管膜下区神经发生的影响。方法建立Ⅰ型糖尿病大鼠模型及胰岛素治疗糖尿病模型,用免疫组织化学方法计数侧脑室室管膜下区BrdU阳性细胞数,并用Morris水迷宫测定大鼠的学习记忆能力。结果糖尿病大鼠SVZ的BrdU细胞数以及学习记忆能力明显下降(P<0.01);用胰岛素治疗,可使上述指标明显上升(P<0.01),并接近正常水平。结论胰岛素治疗对糖尿病大鼠神经干细胞增殖及学习记忆能力均有相似的促进作用。     

APP/PS1转基因小鼠发育过程中神经细胞增殖变化

目的:探讨β-淀粉样前体蛋白基因(β-amyloid precusor protein,APP)和突变早老素1基因(presinilin,PS1)转基因小鼠(APP/PS1)发育过程中齿状回神经细胞增殖规律。方法:取不同发育时间(P14、P30、P180、P360)APP/PS1转基因模型鼠与同时间点对照鼠,用二等分Y型迷宫箱测试小鼠学习记忆能力,BrdU免疫细胞化学观察齿状回内神经细胞增殖变化。结果:随着小鼠的生长发育,BrdU阳性细胞密度逐渐降低,在P360时间点,模型组齿状回BrdU阳性细胞密度比对照组低(P<0.05);其空间识别以及记忆能力明显低于对照组(P<0.01)。结论:发育中的APP/PS1转基因小鼠齿状回内神经细胞增殖减少可能与阿尔茨海默病的学习、记忆能力下降有关。     

慢性复合应激对大鼠学习和记忆功能及齿状回神经前体细胞增殖的影响

为研究慢性复合应激对成年雄性大鼠学习和记忆功能及齿状回(DG)神经前体细胞增殖的影响,将成年雄性Wistar大鼠随机分为对照组和应激组,应激组动物每天交替暴露于复合应激原中,持续6周。应激结束后,用Morris水迷宫测试大鼠空间学习记忆成绩。同时,采用BrdU标记分裂细胞方法,观察比较各组大鼠DG内BrdU阳性细胞数的变化和差异。结果显示:应激组动物的学习与记忆成绩均优于对照组(P<0.05);与对照组相比,应激组大鼠DG内BrdU阳性细胞数量显著增加(P<0.05)。上述结果表明:慢性复合应激导致大鼠的学习与记忆能力加强,DG内BrdU阳性细胞增多,提示神经细胞数量增加可能是应激所引起的大鼠学习记忆能力增强的原因之一。     

外源性褪黑素对成年高血压大鼠神经发生的影响及其与学习记忆的关系

目的探讨褪黑素（MT）对成年高血压大鼠脑神经干细胞的影响及其与学习记忆的关系。方法将30只成年健康雄性wistar大鼠随机分为假手术组、肾血管性高血压组及褪黑素治疗组，用Morris水迷宫测定大鼠的学习记忆能力，并用免疫组织化学方法观察侧脑室室管膜下区（SVZ）和齿状回颗粒下区（SGZ）的BrdU阳性细胞数变化。结果高血压大鼠SVZ和SGZ的BrdU细胞数及学习记忆能力均比假手术组明显下降（P〈0．01），用MT治疗可使上述指标有所逆转至假手术组水平。结论褪黑素可能具有促进高血压大鼠神经干细胞增殖和提高大鼠学习记忆能力的作用。     

全脑照射后对小鼠血脑屏障通透性和室管膜下区细胞增殖的影响

目的:探讨60Co-γ射线(Gy)全脑照射后对小鼠血脑屏障通透性和室管膜下区神经干细胞增殖的影响。方法:112只健康小鼠随机分成0 Gy组(对照组),5 Gy照射组(小剂量照射组),15 Gy照射组(中等剂量照射组)和30 Gy照射组(大剂量照射组),每组28只。各组随机取出7只分别于照射后1周和4周测定各组小鼠脑组织伊文思蓝的含量,7只观察室管膜下区的BrdU+细胞形态和数量。结果:(1)照射后1周,15 Gy组和30Gy组脑组织伊文思蓝含量明显升高(P<0.05),室管膜下区的BrdU+细胞数明显降低(P<0.05);(2)照射后4周,15 Gy剂量照射组脑组织伊文思蓝含量和室管膜下区的BrdU+细胞数均恢复到对照组水平(P>0.05),而30Gy剂量照射组脑组织伊文思蓝含量仍明显升高(P<0.05),BrdU+细胞数也未见恢复(P<0.05)。结论:全脑照射后血脑屏障破坏可能对室管膜下区的细胞增殖有进一步抑制作用。     

香烟烟雾暴露对未成年小鼠齿状回神经发生和小胶质细胞的影响

为探讨香烟烟雾暴露(cigarette smoking exposure,CSE)对未成年小鼠的神经发生及学习记忆的影响,本研究用亲和组织化学方法,以5-溴脱氧尿苷(5-bromodeoxyuridine,BrdU)和西非单叶豆同工凝集素-B4(Bandeirae SimplicifoliaIsolectin-B4,BSI-B4)分别标记新生细胞和小胶质细胞(microglia,MG),观察了CSE小鼠齿状回内的神经发生及MG数目的变化,并通过Morris水迷宫训练测验其空间学习能力。结果显示:CSE下小鼠齿状回内的神经发生降低,MG数目显著减少;而在水迷宫的学习中,CSE组的逃避潜伏期亦明显长于对照组(P<0.05)。上述结果表明CSE损害了未成年小鼠齿状回内的神经发生,抑制了MG的激活,同时小鼠的空间学习能力与神经发生及激活的MG数量平行变化。此结果提示CSE造成的学习能力降低可能与齿状回神经发生及MG减少有关。     

1型糖尿病脑病大鼠空间学习记忆与海马齿状回神经干细胞增殖的观察

目的揭示1型糖尿病继发性脑病变(糖尿病脑病)的发生与海马齿状回颗粒下区(SGZ)神经干细胞增殖之间的关系。方法应用链脲佐菌素(溶解于柠檬酸缓冲液中)腹腔注射,将成年雄性Wistar大鼠建立成1型糖尿病脑病模型;将用柠檬酸缓冲液腹腔注射的大鼠或正常大鼠分别作为载体模型组或正常对照组。在建立模型成功后的60d,用Morris水迷宫和5-溴脱氧尿嘧啶(BrdU,一种神经干细胞合成DNA的标记物)免疫组化方法,观察各组大鼠空间学习记忆能力以及SGZ神经干细胞(BrdU阳性细胞)的变化。结果1型糖尿病脑病模型大鼠的逃避潜伏期和游泳距离均较载体模型组或正常对照组大鼠明显延长(P<0.01);而且该脑病组大鼠SGZ的BrdU阳性细胞数也明显低于载体模型组或正常对照组大鼠(P<0.01)。结论个体内长期缺乏胰岛素可导致SGZ神经干细胞增殖出现障碍,从而引发空间学习记忆能力下降,这可能是诱发1型糖尿病脑病的一个因素。     

远志促进AD模型小鼠神经发生的研究

目的:研究远志对Alzheimer病(AD)模型小鼠神经发生的影响。方法:选用健康成年昆明小鼠随即分为5组,分别为对照组,AD模型组,远志高、中、低剂量干预组。除对照组外,其余四组采用联合给予D-半乳糖和亚硝酸钠腹腔注射造模;远志高、中、低剂量干预组通过灌胃给予不同浓度的远志混悬液,用Morris水迷宫测试其空间学习记忆能力,用5-溴脱氧尿嘧啶(BrdU)免疫组织化学染色标记脑内的新生细胞。结果:远志高、中剂量组学习记忆能力显著高于AD模型组(P0.05);远志高、中剂量组海马齿状回(DG)内的BrdU阳性细胞数显著多于AD模型组(P0.01)。结论:远志能够改善AD小鼠的学习记忆能力,其机理可能与其促进AD模型小鼠海马齿状回的神经发生有关。     

去松果体后成年大鼠学习记忆及侧脑室室管膜下区神经干细胞增殖的变化

目的观察松果体切除对学习记忆及侧脑室室管膜下区(SVZ)神经干细胞增殖的影响。方法将30只成年健康雄性Sprague-Dawley大鼠随机分为非手术、假手术及去松果体组,每组大鼠10只。在建立动物模型16d后,连续5d测定大鼠在Morris水迷宫的学习记忆能力,继之用免疫组织化学方法观察SVZ的增殖细胞核抗原(PCNA)阳性细胞的变化。结果去松果体组大鼠在Morris水迷宫泳游的逃避潜伏期及在原平台象限游泳距离的百分比均较非手术组或假手术组大鼠的明显延长或减少(P<0.01)。去松果体大鼠SVZ的PCNA阳性细胞数也明显低于非手术组或假手术组大鼠(P<0.01)。结论本研究首次观察到,去松果体使体内褪黑素减少,可导致学习记忆功能及SVZ神经干细胞增殖能力出现相似的明显下降趋势,说明褪黑素是确保学习记忆及神经发生得以正常进行的重要激素之一;提示褪黑素可能直接通过作用于神经干细胞上的相应受体以及间接通过提高基底前脑胆碱能系统功能来促进神经干细胞增殖,进而提高嗅觉记忆功能。     

大鼠局灶性短暂脑缺血后前脑室下带的神经发生

目的：观察大鼠短暂性局灶性脑缺血后前脑室下带(SVZ)神经发生的增殖规律。方法：将SD大鼠随机分为正常对照组、假手术组和缺血实验组，缺血实验组再分为缺血后1、4、7、10、14d组。线栓法制作局灶性脑缺血模型；BrdU标记S期细胞并用免疫组织化学方法检测含BrdU的阳性细胞；测量SVZ区域BrdU阳性细胞核的总面积。结果：在缺血侧，缺血后4d BrdU阳性细胞核的总面积明显增加，7d时达到峰值，随后开始下降，在14d时明显下降，但仍高于正常对照组；在缺血对侧，该区域也表现出同样的表达规律，在缺血后10d达到峰值，但增幅较小。结论：短暂性局灶性脑缺血可促进前脑室下带的神经发生，提示成年脑有潜在的自我修复能力。     

Increased adult neurogenesis in the subventricular zone in a rat model of sepsis

Neurogenesis occurs in the adult brain throughout the lives of all mammals. The dentate gyrus (DG) of the hippocampus and the subventricular zone (SVZ) of the lateral ventricles have been established as the primary sites of adult neurogenesis, and recent studies have shown that inflammation has a modulating effect on adult neurogenesis. However, only limited studies have investigated how neurogenesis is affected during sepsis and sepsis-associated encephalopathy. Therefore, we investigated adult neurogenesis in the cecal ligation and puncture (CLP) model of sepsis using a cell proliferation marker, 5-bromo-2′-deoxyuridine (BrdU). Twenty-four rats were placed into the following three groups: an un-operated control group, a sham-operated group that underwent exactly the same procedures except for CLP, and a CLP group that survived surgical procedures and developed signs of sepsis. Rats were monitored for twenty-four hours before they were euthanized and their brains were harvested. Significantly higher numbers of BrdU-immunoreactive cells were observed in the SVZ of the lateral ventricles in the CLP group as compared with both control groups, while no significant difference was found in the number of DG granule cells between the three groups. The majority of BrdU-positive cells in the SVZ co-expressed the neuronal marker doublecortin but not the astrocytic marker glial fibrillary acidic protein. Taken together, our results suggest that sepsis induced by CLP in rats increases region-specific cellular regeneration, in a possible attempt to compensate for the devastating effect of sepsis and sepsis-associated encephalopathy on the brain.     

Wnt/β-catenin信号参与慢性痛引起的小鼠海马神经元发生减少

目的:研究小鼠慢性痛模型中海马神经元发生减弱的现象,并从Wnt/β-catenin信号的角度探索相关机制,以及过表达β-catenin对慢性痛小鼠学习记忆能力的影响。方法:采用选择性坐骨神经损伤(spared nerve injury,SNI)模型,利用Brd U/DCX免疫荧光双标研究神经元发生;采用Wnt信号报告基因Topgal小鼠研究Wnt信号的改变;利用条件性过表达β-catenin的Nestin-Cre ER:β-catenin EX3~(loxp/+)小鼠研究过度激活Wnt信号对慢性痛小鼠海马神经元发生及学习记忆的影响;利用Morris水迷宫评估小鼠的空间学习记忆能力。结果:SNI后小鼠的机械和热痛阈显著下降,持续至少3周。Brd U/DCX免疫荧光双标显示SNI小鼠海马神经元发生明显减弱。Wnt信号报告基因β-gal在海马神经干细胞的表达降低。在SNI小鼠的成年神经干细胞中过表达β-catenin可显著促进海马神经元发生,并增强小鼠的空间记忆能力。结论:Wnt/β-catenin信号参与介导慢性痛引起的海马神经元发生减弱,增强Wnt信号可改善SNI小鼠海马的神经元发生及其学习记忆能力。     

Ischemia induces cell proliferation and neurogenesis in the gerbil hippocampus in response to neuronal death

We studied hippocampal cellular proliferation and neurogenesis processes in a model of transient global cerebral ischemia in gerbils by labelling dividing cells with 5'-Bromo-2'-deoxyuridine (BrdU). Surrounding the region of selective neuronal death (CA1 pyramidal layer of the hippocampus), an important increase in reactive astrocytes and BrdU-labelled cells was detected 5 days after ischemia. A similar result was found in the dentate gyrus (DG) 12 days after ischemia. The differentiation of the BrdU+ cells was investigated 28 days after BrdU administration by analyzing the morphology, anatomic localization and cell phenotype by triple fluorescent labelling (BrdU, adult neural marker NeuN and DNA marker TOPRO-3) using confocal laser-scanning microscopy. This analysis showed increased neurogenesis in the DG in case of ischemia and triple positive labelling in some newborn cells in CA1. Seven brain hemispheres from gerbils subjected to ischemia did not develop CA1 neuronal death; hippocampus from these hemispheres did not show any of the above mentioned findings. Our results indicate that ischemia triggers proliferation in CA1 and neurogenesis in the DG in response to CA1 pyramidal neuronal death, independently of the reduced cerebral blood flow or the cell migration from subventricular zone (SVZ).     

Hippocampus-dependent learning promotes survival of new neurons in the dentate gyrus at a specific time during cell maturation

Adult neurogenesis in the hippocampus continues throughout life and may play an important role in hippocampus-dependent learning and memory. Previous research has been equivocal, demonstrating that spatial learning may enhance, decrease or not significantly affect the survival of new neurons. A potential cause of these varying results may be differences in when bromodeoxyuridine (BrdU) was administered relative to spatial training. We examined whether the time elapsed between BrdU administration and spatial learning would alter the survival of the labeled cells. We injected rats with BrdU once on day 0 and then trained in the standard place version of the Morris water task on days 1-5, 6-10 or 11-15 after BrdU injection. We found an enhancement of neurogenesis in the hippocampus only when BrdU was administered 6 days prior to the beginning of spatial training. There was no significant change in hippocampal neurogenesis for groups that started training either 1 or 11 days following BrdU administration. This suggests that a critical period exists in the development of new neurons during which time their survival may be altered by activation of the hippocampus. Furthermore, when dividing rats into poor versus good learners based on overall performance using a median split, only poor place learners and not good place learners exhibit increased hippocampal neurogenesis compared with cue learning, collapsed across time of training. These findings provide further evidence of a link between learning and adult neurogenesis.     

母代高脂饮食对雄性后代小鼠青春期后期运动能力及学习记忆行为的影响

目的:研究母代高脂饮食(high-fat diet,HFD)对雄性后代小鼠青春期后期运动能力及学习记忆行为的影响及机制.方法:通过16周高脂饮食喂养母鼠直至哺乳期结束建立母鼠肥胖模型,以子代雄鼠作为主要研究对象.通过足迹分析和转棒实验研究了子代小鼠的运动协调性,通过旷场实验研究了雄性子代小鼠运动能力的变化,通过水迷宫和...