小鼠在体海马长时程增强记录技术

目的:建立记录小鼠在体海马"前穿通纤维-齿状回"(PP-DG)神经通路长时程增强(LTP)的方法.方法:动物麻醉后固定于立体定位仪上,参照立体定位参数将刺激电极插入至前穿通纤维,记录电极插入至DG颗粒细胞层,而后进行LTP的诱发和记录.结果:对各种实验条件优化后,成功记录了Balb/c小鼠海马PP-DG通路LTP.应用该方法对快速老化模型小鼠(SAM)的快速老化亚系SAMP8和抗快速老化亚系SAMRl海马神经突触可塑性进行考察,结果表明在体海马LTP与脑片LTP和行为学实验结果相符.结论:成功建立了小鼠在体海马PP-DG通路LTP的记录方法,可用于整体动物神经突触可塑性的评价.     

快速老化模型小鼠海马正反向抑制消减cDNA文库的构建

目的:构建快速老化模型小鼠(SAM)海马正反向抑制消减cDNA文库,以揭示SAMP8学习记忆脑老化的机制,同时为研究阿尔茨海默病(AD)的发病机制提供线索。方法:以快速老化模型小鼠SAMP8和SAMR1海马的总RNA为材料,采用抑制消减杂交方法和蓝白斑筛选克隆构建文库,并用PCR鉴定了文库的质量。结果:成功构建了12月龄雄性SAMP8和SAMR1海马的正反向抑制消减cDNA文库,其中正向文库包含864个克隆,反向文库包含960个克隆,阳性克隆率为96.16%,插入片段范围为250～2000bp。结论:SAMP8和SAMR1海马的正反向抑制消减cDNA文库的构建,为进一步筛选鉴定SAMR1和SAMP8海马差异表达基因提供了丰富的实验材料。     

黄连解毒汤对快速老化小鼠海马基因表达的影响

目的：研究黄连解毒汤（HL）对快速老化小鼠亚系SAMP8海马差异表达基因的影响,揭示HL改善认知功能障碍的分子机制。方法：应用快速老化小鼠亚系SAMP8和SAMR1海马差异表达cDNA芯片,比较了SAMP8和SAMR1、石杉碱甲处理的SAMP8和SAMP8对照,以及HL处理的SAMP8和SAMP8对照的基因表达谱,并对HL的药物反应基因进行了比较;采用实时荧光定量PCR技术对芯片结果进行了验证。结果：给予SAMP8HL后,对SAMP8海马基因表达具有明显的调节作用。差异表达基因包括信号转导基因Dusp12、Rps6ka1、Penk1、Nope,Leng8,蛋白质代谢相关基因Ttc3、Amfr、Prr6、Ube2以,核酸代谢基因Fhit、Itm2c、Cstf2t、Ddx3x、Ercc5、Pcgfr6,能量代谢基因Stubl,免疫反应相关基因Clqb,转录调节基因Dlertdl6le、Gcn512、Ssu72,细胞生长相关基因Ngrn、Anln,递质转运相关基因Slc17a7,以及功能未知基因12个。结论：提示HL对于认知功能的改善可能是通过调节信号转导、突触传递、蛋白质和能量代谢、细胞增殖分化等途径发挥作用的;研究中发现的HL作用基因可能是改善学习记忆的潜在靶标。     

脑内胆碱能M受体和肾上腺素能α_2受体与老年记忆衰退的关系

很多资料表明中枢胆碱能系统的变化在老年记忆减退中起重要作用。有人发现海马与大脑皮层中胆碱能M受体的明显减少可能是正常老年记忆衰退的指标。但是越来越多的学者认为记忆功能的机理不只是胆碱能系统的作用,而是多种神经递质系统与神经活性物质共同协调和制约的结果,如有人观察到大脑皮层和海马肾上腺素能神经元的退变与记忆衰退有密切的关系。本文试图同时测定老年大鼠的大脑皮层、海马和下丘脑内M受体以及α_2肾上腺素能受体     

钙离子调节的转录因子NF-κB激活参与小鼠记忆功能与行为调控

NF κB是重要的核转录因子,最近,美国研究人员DavidBaltimore等惊奇地发现,NF κB在行为学中枢调控过程中亦起重要作用。他们发现,敲除NF κB分子P6 5基因的小鼠的海马细胞虽然存在NF κB的其他亚基,但突触刺激引发的NF κB核转运却被降低。行为学研究亦表明,虽然P6 5基因敲除小鼠具有正常发育的中枢神经系统和正常的日常行为,但在辐射臂状迷宫(radialarmmaze,RAM)实验中,P6 5基因敲除小鼠对场景的学习和记忆能力以及探寻食物的能力均明显低于野生型小鼠,尽管实验中它们表现出与野生型小鼠相同的探寻行为(exploratorybehavior)和…     

艾燃烧生成物对SAM小鼠学习记忆行为的影响

目的：艾灸不仅可以延年益寿而且可以未病先防。然而仅有少量研究证实,艾灸的燃烧生成物具有抗氧化作用从而延缓衰老。本试验从行为学方面研究艾燃烧生成物对快速老化模型小鼠SAM—W8学习记忆行为的影响。方法：选用6月龄雄性快速老化模型（SAM）小鼠50只,其中SAM—R／1系10只作为空白组,SAM—W8系40只随机分为模型组、单纯艾烟熏吸组、无烟艾灸组和常规艾灸组,每组10只。选取关元穴为治疗穴位,令常规艾灸关元组小鼠在艾灸关元穴的同时处在一定浓度艾烟的环境中;单纯艾烟熏吸组小鼠处在与常规艾灸关元组相同浓度的艾烟环境但不艾灸其穴位;而无烟艾灸关元组则是在艾灸小鼠关元穴的同时立即将艾烟抽除;其余空白组和模型组小鼠进行相同的空白抓取。治疗前后分别进行学习记忆行为的被动逃避试验,并对实验结果进行分析。结果：与空白组比较,治疗前模型组及治疗各组小鼠进行被动逃避试验的潜伏期均明显变短,有显著性差异（P〈0．05,P〈0．05,P〈0．01,P〈0．01）,治疗后模型组及常规艾灸关元组小鼠治疗后潜伏期均明显缩短,有显著性差异（P〈0．01,P〈0．05）;与模型组比较,各治疗组小鼠治疗后潜伏期均明显延长,有显著差异（P〈0．01,P〈0．01,P〈0．05）。与治疗前比较,各治疗组治疗后潜伏期均较前明显延长,有显著性差异（P〈0．01,P〈0．05,P〈0．05）。结论：艾燃烧生成物可延长快速老化模型小鼠被动逃避试验的潜伏期。提示其在一定程度上改善老化模型小鼠的学习记忆功能,为今后艾灸抗衰老在临床上的应用开辟了新思路。     

GDNF在慢性应激和老化致小鼠行为与认知损伤中的作用

目的:探讨慢性应激对不同月龄小鼠空间学习记忆功能的影响,以及小鼠前脑皮层和海马胶质细胞源性神经营养因子(GDNF)的作用。方法:采用多因素慢性应激动物模型,通过旷场试验和Morris水迷宫试验,检测不同月龄小鼠行为及空间学习记忆能力,并检测GDNF在小鼠脑海马和前脑皮层的表达。结果:与青年(2月龄)小鼠比较,老年(15月龄)小鼠的自发活动和探究行为明显减少,空间学习记忆能力明显降低(P<0.05,P<0.01),且海马CA3区、齿状回和前脑皮层GDNF表达明显下降(P<0.05,P<0.01);在慢性应激后,与对照组比较,青年和老年应激组小鼠的自发活动和探究行为显著减少,空间学习记忆能力显著降低(P<0.05,P<0.01),且小鼠前脑皮层和海马GDNF表达显著下降(P<0.05,P<0.01),老年应激小鼠变化更加显著。结论:脑的老化和慢性应激导致小鼠行为及空间学习记忆功能改变,可能与海马和前脑皮层神经元GDNF表达的变化密切相关。     

3,4-O-异亚丙基莽草酸对SAMP-8快速老化小鼠认知功能的影响

3,4-O-异亚丙基莽草酸(ISA)是从木兰科植物八角茴香(Illicium verum Hook.Fil.)中提取的有效成分莽草酸的衍生物,具有抗炎、抗血栓和抗缺血性脑损伤等作用,关于其对于阿尔茨海默病的作用尚不清楚.本研究发现,ISA可显著改善SAMP-8快速老化小鼠(Mus musculus)的空间学习记忆能力,降低脑皮层IL-1,IL-6,TNF-?和Caspase-3水平,降低海马区p-Tau蛋白表达,升高海马区沉默信息调节因子2同源蛋白1(SIRT1)蛋白表达.本研究表明,ISA可通过抑制过度神经炎性反应、增加SIRT1表达,降低Tau蛋白磷酸化,改善阿尔茨海默病造成的认知功能损伤.     

灵芝多糖对AD大鼠海马组织c-fos基因表达的影响

目的研究灵芝多糖(GLP)对AD大鼠组织c-fos基因表达的影响。方法双侧海马内一次性注射β-淀粉样多肽25-35片段(Aβ25-35)制作大鼠AD模型,24h后治疗组用灵芝多糖给予腹腔注射7d,第8d进行Morris水迷宫检测大鼠空间学习记忆能力变化。结束后采用HE染色检测海马神经元的结构变化,免疫组织化学方法检测c-fos基因的表达以及灵芝多糖对其的影响。结果海马内注射Aβ25-35后海马细胞增生、聚集、核边聚、脆裂。GLP组病变则显著减轻,且c-fos基因表达相对AD模型组明显减少。结论灵芝多糖能明显改善AD模型大鼠低下的空间学习记忆能力,显著降低模型大鼠海马组织c-fos基因的表达,对老年性痴呆大鼠学习记忆能力可能有增强和提高作用。     

选择性敲除小鼠神经细胞adam10基因导致胼胝体和海马联合发育不全

目的探讨adam 10基因在小鼠神经系统发育的作用。方法将gfapcre转基因鼠和adam10loxlox转基因鼠杂交,得到神经细胞特异性adam10基因敲除鼠(gfapcre-adam10loxlox);在出生后第14d对小鼠大脑切片行HE染色和免疫组织化学染色,观察adam10基因敲除后神经系统发育情况。结果选择性敲除小鼠神经细胞adam10基因(gfapcre-adam10loxlox)后,小鼠可存活至出生后3w左右;HE染色发现胼胝体缺失,海马发育不全,髓鞘碱性蛋白(myelin basic protein,MBP)免疫荧光染色发现髓鞘发育异常。结论 Adam10基因在小鼠神经系统发育中具有重要作用,选择性敲除小鼠神经细胞adam10基因导致胼胝体和海马联合发育不全,髓鞘发育异常。     

Senescence-Accelerated Mouse (SAM) with Special References to Neurodegeneration Models,SAMP8 and SAMP10 Mice

The SAM strains, a group of related inbred strains consisting of senescence-prone inbred strains (SAMP) and senescence-resistant inbred strains (SAMR), have been successfully developed by selective inbreeding of the AKR/J strain of mice donated by the Jackson laboratory in 1968. The characteristic feature of aging common to the SAMP and SAMR is accelerated senescence and normal aging, respectively. Furthermore, SAMP and SAMR strains of mice manifest various pathobiological phenotypes spontaneously. Among SAMP strains, SAMP8 and SAMP10 mice show age-related behavioral deterioration such as deficits in learning and memory, emotional disorders (reduced anxiety-like behavior and depressive behavior) and altered circadian rhythm associated with certain pathological, biochemical and pharmacological changes. Here, the previous and recent literature on SAM mice are reviewed with an emphasis on SAMP8 and SAMP10 mice. A spontaneous model like SAM with distinct advantages over the gene-modified model is hoped by investigators to be used more widely as a biogerontological resource to explore the etiopathogenesis of accelerated senescence and neurodegenerative disorders.     

Proteomic analysis of specific brain proteins in aged SAMP8 mice treated with alpha-lipoic acid: implications for aging and age-related neurodegenerative disorders

Free radical-mediated damage to neuronal membrane components has been implicated in the etiology of Alzheimer's disease (AD) and aging. The senescence accelerated prone mouse strain 8 (SAMP8) exhibits age-related deterioration in memory and learning along with increased oxidative markers. Therefore, SAMP8 is a suitable model to study brain aging and, since aging is the major risk factor for AD and SAMP8 exhibits many of the biochemical findings of AD, perhaps as a model for and the early phase of AD. Our previous studies reported higher oxidative stress markers in brains of 12-month-old SAMP8 mice when compared to that of 4-month-old SAMP8 mice. Further, we have previously shown that injecting the mice with alpha-lipoic acid (LA) reversed brain lipid peroxidation, protein oxidation, as well as the learning and memory impairments in SAMP8 mice. Recently, we reported the use of proteomics to identify proteins that are expressed differently and/or modified oxidatively in aged SAMP8 brains. In order to understand how LA reverses the learning and memory deficits of aged SAMP8 mice, in the current study, we used proteomics to compare the expression levels and specific carbonyl levels of proteins in brains from 12-month-old SAMP8 mice treated or not treated with LA. We found that the expressions of the three brain proteins (neurofilament triplet L protein, alpha-enolase, and ubiquitous mitochondrial creatine kinase) were increased significantly and that the specific carbonyl levels of the three brain proteins (lactate dehydrogenase B, dihydropyrimidinase-like protein 2, and alpha-enolase) were significantly decreased in the aged SAMP8 mice treated with LA. These findings suggest that the improved learning and memory observed in LA-injected SAMP8 mice may be related to the restoration of the normal condition of specific proteins in aged SAMP8 mouse brain. Moreover, our current study implicates neurofilament triplet L protein, alpha-enolase, ubiquitous mitochondrial creatine kinase, lactate dehydrogenase B, and dihydropyrimidinase-like protein 2 in process associated with learning and memory of SAMP8 mice.     

The Hippocampal Proteomic Analysis of Senescence-Accelerated Mouse: Implications of Uchl3 and Mitofilin in Cognitive Disorder and Mitochondria Dysfunction in SAMP8

Senescence-accelerated mouse prone 8 (SAMP8) is considered as a useful animal model for age-related learning and memory impairments. Hippocampus, a critical brain region associated with cognitive decline during normal aging and various neurodegenerative diseases, appeared a series of abnormalities in SAMP8. To investigate the molecular mechanisms underlying age-related cognitive disorders, we used 2-DE coupled with MALDI TOF/TOF MS to analyze the differential protein expression of the hippocampus of SAMP8 at 6-month-old compared with the age-matched SAM/resistant 1 (SAMR1) which shows normal aging process. Two proteins were found to be markedly changed in SAMP8 as compared to SAMR1: ubiquitin carboxyl-terminal hydrolase L3 (Uchl3), implicating in cytosolic proteolysis of oxidatively damaged proteins, was down-regulated while mitofilin, a vital protein for normal mitochondria function, exhibited four isoforms with a consistent basic shift of isoelectric point among the soluble hippocampal proteins in SAMP8 compared with SAMR1. The alterations were confirmed by Western blotting analysis. The analysis of their expression changes may shed light on the mechanisms of learning and memory deficits and mitochondrial dysfunction as observed in SAMP8.     

Proteomic analysis for protein carbonyl as an indicator of oxidative damage in senescence-accelerated mice

The senescence-accelerated prone mouse strain 8 (SAMP8) exhibits a remarkable age-accelerated deterioration in learning and memory. In this study, we identified carbonyl modification, a marker of protein oxidation, in liver and brain of SAMP8 from peptide mass fingerprints using MALDI-TOF mass spectrometry in combination with LC-MS/MS analysis. Carbonyl modification of Cu,Zn-superoxide dismutase (Cu,Zn-SOD) in liver at 3 month and hippocampal cholinergic neurostimulating peptide precursor protein (HCNP-pp) in brain at 9 month were higher in SAMP8 compared with control SAMR1. We demonstrated carbonyl modification of purified Cu,Zn-SOD increased by the reaction with H₂O₂. Therefore, progressive accumulation of oxidative damage to Cu,Zn-SOD, may cause dysfunction of defense systems against oxidative stress in SAMP8 with a higher oxidative states, leading to acceleration of aging. Furthermore, carbonyl modification of HCNP-pp may be involved in pathophysiological alterations associated with deterioration in the learning and memory in the brain seen in SAMP8.     

Frontiers of Model Animals for Neuroscience:Two Prosperous Aging Model Animals forPromoting Neuroscience Research

A model animal showing spontaneous onset is a useful tool for investigating the mechanism of disease. Here, I would like to introduce two aging model animals expected to be useful for neuroscience research: the senescence-accelerated mouse (SAM) and the klotho mouse. The SAM was developed as a mouse showing a senescence-related phenotype such as a short lifespan or rapid advancement of senescence. In particular, SAMP8 and SAMP10 show age-related impairment of learning and memory. SAMP8 has spontaneous spongy degeneration in the brain stem and spinal cord with aging, and immunohistochemical studies reveal excess protein expression of amyloid precursor protein and amyloid β in the brain, indicating that SAMP8 is a model for Alzheimer’s disease. SAMP10 also shows age-related impairment of learning and memory, but it does not seem to correspond to Alzheimer’s disease because senile plaques primarily composed of amyloid β or neurofibrillary tangles primarily composed of phosphorylated tau were not observed. However, severe atrophy in the frontal cortex, entorhinal cortex, amygdala, and nucleus accumbens can be seen in this strain in an age-dependent manner, indicating that SAMP10 is a model for normal aging. The klotho mouse shows a phenotype, regulated by only one gene named α-klotho, similar to human progeria. The α-klotho gene is mainly expressed in the kidney and brain, and oxidative stress is involved in the deterioration of cognitive function of the klotho mouse. These animal models are potentially useful for neuroscience research now and in the near future.     

Acupuncture accelerates neural regeneration and synaptophysin production after neural stem cells transplantation in mice

BACKGROUNDSynaptophysin plays a key role in synaptic development and plasticity of neurons and is closely related to the cognitive process of Alzheimer’s disease (AD) patients. Exogenous neural stem cells (NSCs) improve the damaged nerve function. The effects of Sanjiao acupuncture on cognitive impairment may be related to the regulation of the NSC microenvironment.AIMTo explore the anti-dementia mechanism of acupuncture by regulating the NSC microenvironment.METHODSNSCs were isolated from pregnant senescence-accelerated mouse resistant 1 (SAMR1) mice, labeled with BrdU, and injected into the hippocampus of senescence-accelerated mouse prone 8 (SAMP8) mice. Eight-month-old senescence-accelerated mice (SAM) were randomly divided into six groups: SAMR1 (RC), SAMP8 (PC), sham transplantation (PS), NSC transplantation (PT), NSC transplantation with acupuncture (PTA), and NSC transplantation with non-acupoint acupuncture (PTN). Morris water maze test was used to study the learning and memory ability of mice after NSC transplantation. Hematoxylin-eosin staining and immunofluorescence were used to observe the his-topathological changes and NSC proliferation in mice. A co-culture model of hippocampal slices and NSCs was established in vitro, and the synaptophysin expression in the hippocampal microenvironment of mice was observed by flow cytometry after acupuncture treatment.RESULTSMorris water maze test showed significant cognitive impairment of learning and memory in 8-mo-old SAMP8, which improved in all the NSC transplantation groups. The behavioral change in the PTA group was stronger than those in the other two groups (P < 0.05). Histopathologically, the hippocampal structure was clear, the cell arrangement was dense and orderly, and the necrosis of cells in CA1 and CA3 areas was significantly reduced in the PTA group when compared with the PC group. The BrdU-positive proliferating cells were found in NSC hippocampal transplantation groups, and the number increased significantly in the PTA group than in the PT and PTN groups (P < 0.05). Flow cytometry showed that after co-culture of NSCs with hippocampal slices in vitro, the synaptophysin expression in the PC group decreased in comparison to the RC group, that in PT, PTA, and PTN groups increased as compared to the PC group, and that in the PTA group increased significantly as compared to the PTN group with acupoint-related specificity (P < 0.05).CONCLUSIONAcupuncture may promote nerve regeneration and synaptogenesis in SAMP8 mice by regulating the microenvironment of NSC transplantation to improve the nerve activity and promote the recovery of AD-damaged cells.     

Deficiencies of hippocampal Zn and ZnT3 accelerate brain aging of Rat

We examined the link of hippocampal Zn to the functional impairments with aging using senescence-accelerated mouse prone 10 (SAMP10) with deficits in learning and memory. Zn in hippocampal mossy fiber pathway was less distributed in aged SAMP10 than that in the age-matched control. Furthermore, expression of Zn transporter 3, ZnT3, which plays to accumulate Zn in synaptic vesicles in the mossy fiber pathway, was markedly reduced in the hippocampal region even in young SAMP10. Moreover, excessive presynaptic release of glutamate as well as glycine and expression of glial fibrillary acidic protein, a marker of neuronal cell injury, were observed in the hippocampus of aged SAMP10 compared to the control. The present results suggest that age-dependent deficiencies of Zn in synaptic vesicles of the mossy fiber pathway induced by low expression of ZnT3 cause glutamatergic excitotoxicity in the hippocampal neurons and the deterioration of learning and memory in SAMP10.     

Superoxide dismutase in senescence-accelerated mouse retina

To examine the relationship between retinal ageing and superoxide dismutase, we studied the dismutase, with immunohistochemistry and immunoquantitative analysis, in the retina of senescence-accelerated mice P8/Ta (SAMP8/Ta) 3 and 12 months after birth. Accelerated senescence-resistant mice R1TA (SAMR1TA), which show no acceleration of senescence, were used as controls. In SAMP8/Ta, copper-zinc superoxide dismutase and manganese superoxide dismutase immunoreactivity in the photoreceptor inner segments, the outer nuclear layer and the inner nuclear layer increased earlier than in the controls. The increase in both superoxide dismutases with age occurred not only in SAMP8/Ta retinas but also in the controls. In conclusion, we propose the possibility that SAMP8/Ta undergo deterioration not only of learning and memory but also acceleration of senescence in the retina. The dismutases also appear to increase with normal ageing in the retina.     

APP5肽对糖尿病小鼠学习记忆功能与海马神经元蛋白表达的影响

目的研究APP5肽对糖尿病模型小鼠学习记忆能力及海马神经元蛋白表达的影响。方法用链脲佐菌素诱发小鼠糖尿病模型,应用APP5肽（0.0014 mg/kg）皮下注射治疗,5周后进行Morris水迷宫试验;小鼠脑组织海马做Akt、PI3K、P-CREB、Bcl-2、Bax、CytoC免疫组织化学染色;另一部分鼠脑海马,做Bcl-2、Bax抗体蛋白免疫印记。结果（1）水迷宫试验：糖尿病模型小鼠到达站台游动时间比正常对照组延长（P〈0.01）;而APP5肽皮下注射治疗组较DM组动物分别缩短（P〈0.01）。（2）神经免疫组织化学实验和Western blot：给予APP5肽糖尿病小鼠与对照组小鼠海马组织内神经元表达细胞存活相关蛋白及抗凋亡相关蛋白PI3K、Akt、P-CREB、Bcl-2阳性细胞数相似,明显高于糖尿病小鼠（P〈0.01）;APP5肽给予糖尿病小鼠与对照组小鼠表达凋亡蛋白Bax、cytoC阳性细胞数相似,明显少于糖尿病小鼠（P〈0.01）。Western blot结果相同。结论糖尿病小鼠海马神经元表达细胞存活相关蛋白下降,神经元表达细胞凋亡相关蛋白增加,导致其学习记忆能力下降。APP5肽应用可以使上述蛋白恢复到接近正常,从而改善糖尿病小鼠学习记忆能力。