APP/PS1阿尔茨海默病转基因动物模型前联合异常改变

背景: 阿尔茨海默病研究大多主要集中在淀粉样β蛋白和神经元死亡之间的关系,但是对白质损害研究却鲜有报道。 目的：观察APP/PS1阿尔茨海默病转基因动物模型前联合病理改变特点。 设计、时间及地点：以组织学改变为依据,分组对照观察,于2007-09/2008-09在华中科技大学同济医学院附属同济医院神经科实验室完成。 材料：雌性转基因APP/PS1小鼠(表达人突变的PS1(M146L)基因和APP (KM670/ 671NL,V717I)基因, 对照组老鼠选用的是没有淀粉样蛋白沉积的雌性PS1小鼠。分为年轻组(2月龄,包括8 只APP/PS1,7只PS1)和老年组(24月龄,包括6 只APP/ PS1,7只PS1)。 方法：利用刚果红和免疫组织化学方法观测该AD转基因模型脑内淀粉样改变;采用氯化金髓鞘染色方法和轴突免疫组织化学染色,利用吸光度方法对前联合轴突密度和髓鞘化程度的染色进行相对吸光度定量分析。 主要观察指标：①细胞内和细胞外淀粉样β蛋白的染色。②在冠状位前联合的平均面积大小测量。③前联合处轴突密度和髓鞘化程度定量相对吸光度值。 结果：在老年组APP/PS1小鼠,大量的刚果红阳性染色出现在皮质,海马以及丘脑, 前联合也出现阳性染色;细胞内淀粉样β蛋白仅出现在年轻组APP/PS1的皮质结构中。在老年组PS1组小鼠,前联合的表面积大小比年轻组PS1和老年组APP/PS1组小鼠都有显著的增长。老年组包括APP/PS1和PS1组轴突的染色都有显著的下降,髓鞘化程度比年轻组有增高趋势。不同表型分析显示,轴突密度和髓鞘化程度在年轻组APP/PS1和PS1组相当;老年APP/PS1组轴突密度比PS1组有显著的下降,老年组APP/PS1小鼠髓鞘化程度与PS1无显著差别。 结论：随着年龄的增长,APP/PS1阿尔茨海默病转基因小鼠模型前联合存在着轴突的丢失,髓鞘相对保持完整。淀粉样β蛋白对轴突有直接的毒性作用。     

能量限制对APP/PS1双转基因大鼠脑内Aβ的影响

目的探讨能量限制(CR)对APP/PS1双转基因大鼠脑内Aβ的影响,并探讨其可能的机制。方法将24只5月龄APP/PS1双转基因痴呆大鼠随机分为对照组、CR-1组、CR-2组,分别给予自由进食、正常进食量的80%及70%饲养4w,通过Morris水迷宫测试认知能力及免疫组织化学染色观察脑内Aβ阳性细胞数。结果在Morris水迷宫测试在定位航行实验第5天,CR-2组大鼠的逃避潜伏期较对照组明显缩短(P0.05),穿越平台次数明显增多(P0.05);而CR-1组较对照组无显著差异(P0.05)。CR-2组海马区的Aβ阳性细胞数低于对照组,差异有统计学意义(P0.05);而CR-1组较对照组差异无统计学意义(P0.05)。结论 70%的CR可以改善APP/PS1双转基因大鼠的认知能力,其机制可能与减少大鼠脑内Aβ的沉积有关。     

EGCG通过NGF/TrkA通路影响APP/PS1小鼠脑内Aβ沉积的研究

目的探讨绿茶的有效多酚成分表没食子儿茶素没食子酸酯(EGCG)对淀粉样前体蛋白/早老素基因(APP/PS1)转基因小鼠脑内β-淀粉样蛋白(Aβ)沉积及其对海马内神经生长因子(NGF)相关神经生长因子受体(TrkA)信号通路的影响。方法采用免疫组化及Western blot法分别检测小鼠海马Aβ1-40、淀粉样前体蛋白(APP)的蛋白表达水平,Western blot检测小鼠海马NGF及神经生长因子前体(proNGF)的表达水平及其共同受体TrkA下游细胞外信号调节激酶(ERK)通路相关蛋白的表达水平。结果免疫组化结果显示,模型组小鼠海马内Aβ1-40和APP表达(42.35±8.25、143.63±24.30)较对照组(13.04±4.36、19.89±4.93)均显著增加(均P0.05),治疗组(19.72±6.55、38.07±18.19)较模型组明显降低(均P0.05)。Western blot结果显示,与对照组(均为100)比较,模型组小鼠海马内Aβ1-40、APP的相对表达量增加(分别为363.39±45.77、499.51±65.75,均P0.01),与模型组比较,治疗组Aβ1-40、APP相对表达量显著降低(分别为179.77±18.17、160.42±44.55,均P0.01)。与对照组(均为100)比较,模型组NGF(16.39±4.03)、pro-NGF(25.92±5.37)、NGF/pro-NGF(63.64±10.68)、p-TrkA(7.92±2.13)、p-c-raf(7.37±2.66)、p-ERK1/2(13.53±4.44)及pCREB(3.95±1.56)的相对表达量降低(均P0.05);与模型组比较,治疗组NGF(80.78±12.18)、pro-NGF(48.63±3.83)、NGF/pro-NGF(165.84±19.02)、p-TrkA(72.33±6.21)、p-c-raf(88.12±5.33)、p-ERK1/2(60.21±10.34)及p-CREB(25.31±8.48)的相对表达量明显增加(均P0.05)。治疗组与对照组上述指标比较差异均无统计学意义(均P0.05)。结论 EGCG主要通过上调NGF/proNGF比例,增加NGF的相对表达,继而激活其下游特异性TrkA通路,显著增加TrkA、c-raf、ERK1/2及其下游效应蛋白CREB的磷酸化水平,从而抑制Aβ1-40和APP的表达,改善学习记忆障碍,发挥神经保护作用。     

加兰他敏对APP/PS1转基因小鼠海马区星形胶质细活化及C/EBPβ表达的影响

目的研究加兰他敏对APP/PS1转基因小鼠海马区星形胶质细胞活化、C/EBPβ表达及行为学的影响。方法选取10月龄雄性APP/PS1转基因小鼠20只,随机分为模型对照组(10只)和治疗组(10只),同月龄、同背景的C57BL/6野生型雄性小鼠10只作为正常对照组。治疗组皮下注射加兰他敏溶液5mg/kg,2次/d,连续治疗8周,正常对照组和模型对照组给予皮下注射等量生理盐水。应用Morris水迷宫实验于干预治疗8周后开始测定各组小鼠空间学习记忆能力,连续7d,采用免疫组织化学、免疫荧光及Western-blot方法观察各组小鼠海马区星形胶质细胞活化及C/EBPβ表达水平。结果与正常对照组相比,模型对照组和治疗组小鼠Morris检测第5、6天平均逃避潜伏期延长,穿越平台次数减少(P0.05,P0.05),而治疗组其逃避潜伏期较模型对照组缩短(P0.05),穿越平台次数增多(P0.05);同时治疗组小鼠星形胶质细胞活化被明显抑制,胶质纤维酸性蛋白(GFAP)的阳性表达面积〔(5.003±0.823)%〕及C/EBPβ的表达量(87.711±14.622)较模型对照组〔(7.116±1.040)%,119.920±16.901〕明显减少(P0.05,P0.05)。结论加兰他敏改善APP/PS1转基因AD小鼠的学习记忆能力可能与其抑制星形胶质细胞的活化及C/EBPβ的表达有关。     

乳铁蛋白对APP/PS1转基因小鼠神经病理的抑制作用

目的 探究乳铁蛋白(lactoferrin,Lf)对阿尔茨海默病(Alzheimer's disease,AD)模型小鼠神经病理的抑制作用。方法选用6个月龄雄性APP/PS1双转基因小鼠作为AD动物模型,将16只小鼠随机分为对照组和Lf组。各组对应给予生理盐水或人Lf(2mg·kg~(-1)),鼻饲3个月。免疫荧光激光共聚焦技术检测β?淀粉样蛋白(β?amyloid,Aβ)神经斑与星形胶质细胞和小胶质细胞的共定位;尼氏染色检测神经元的功能状态;Western blot检测神经核抗原(NeuN)、谷胱甘肽过氧化物酶(GPX4)和线粒体转录因子A(TFAM)的表达水平。结果 与对照组比较,鼻饲Lf组小鼠脑内Aβ阳性染色减弱,Aβ神经斑周围的星形胶质细胞的激活状态受抑制而小胶质细胞数量减少不明显,海马神经元的尼氏染色增强,GPX4、TFAM和NeuN等蛋白的表达上调。结论 人Lf可通过抑制神经炎症和氧化应激,从而有效保护APP/PS1小鼠的神经元,减缓APP/PS1转基因小鼠病理生理进程。     

APP/PS1转基因AD模型小鼠海马自噬及相关信号通路研究

目的 研究β-淀粉样前体蛋白/早老素1(amyloid precursor protein/presenilin 1,APP/PS1)双转基因阿尔茨海默病(Alzheimer disease,AD)模型小鼠不同年龄阶段自噬水平变化,及蛋白激酶B(protein kinase B,Akt)/哺乳动物雷帕霉素靶蛋白(mam...     

APP/PS1双转基因小鼠早期记忆功能障碍与胆碱能系统的关系研究

目的观察转APP/PS1基因阿尔茨海默病小鼠(APP/PS1小鼠)早期空间学习记忆功能及乙酰胆碱能系统的变化以及两者之间的相关性,探讨阿尔茨海默病早期学习记忆障碍的发病机制。方法应用Morris水迷宫法评定3月龄APP/PS1小鼠及相应野生型(WT)小鼠的空间学习记忆功能;采用免疫组织化学及组织化学染色方法检测脑组织中β-淀粉样蛋白(Aβ)斑块沉积情况;采用ELISA法检测脑组织中乙酰胆碱(ACh)含量以及胆碱乙酰转移酶(ChAT)和乙酰胆碱酯酶(AChE)活性,并探讨小鼠脑组织中ACh含量与其空间记忆能力、ChAT活性的相关性。结果水迷宫评定结果显示两组小鼠到达平台的潜伏期无统计学差异(P>0.05);APP/PS1小鼠在目标象限的游泳时间百分比〔(29.02±4.27)%〕和距离百分比〔(28.85±3.77)%〕较WT小鼠均下降(P<0.05)。APP/PS1小鼠脑组织中尚无Aβ斑块的沉积。APP/PS1小鼠脑组织中ACh含量〔(45.23±1.40)ng/g prot〕和ChAT活性〔(279.53±12.13)U/g组织湿重〕均较WT小鼠〔分别为(54.08±4.84)ng/gprot、(315.84±11.32)U/g组织湿重〕显著降低(P<0.05),两组小鼠脑组织中AChE活性无统计学差异(P>0.05)。小鼠脑组织中ACh含量与其空间记忆功能(目标象限航行时间百分比、目标象限航行路程百分比)呈正相关(r=0.861、r=0.874,P<0.05),ACh含量与ChAT活性呈正相关(r=0.926,P<0.05)。结论 APP/PS1小鼠空间记忆功能障碍、ACh含量减少和ChAT活性降低可发生于Aβ斑块沉积之前。脑组织中ACh含量减少和ChAT活性降低可能与APP/PS1小鼠记忆功能损害密切相关。     

转VEGF基因内皮祖细胞移植治疗阿尔茨海默病模型小鼠的研究

目的 将体外诱导的血管内皮祖细胞（EPCs）转入血管内皮生长因子（VEGF）基因,并定向移植到AD 模型鼠脑内海马区,观察该部位及邻近部位的血管重建以及内皮细胞功能的改善情况,为AD的治疗提供研究基础。方法 采用体外分离培养小鼠骨髓源性EPCs。构建的携带人VEGF165 基因的pcDNA3.1 质粒转染至EPCs,观察EPCs 表达VEGF 情况。采用APP/PS1 双转基因鼠模型,将转染人VEGF165 基因的EPCs 移植至模型鼠脑内,观察小鼠行为学的变化、Aβ 含量,以及血管的形成情况。结果 将转染VEGF基因的EPCs移植入小鼠的海马区后,动物在第4,5,6 天进行空间导航试验发现,与对照组比较,平均潜伏期明显缩短（P＜ 0.05）;免疫组化结果显示,与对照组、EPCs 组比较,EPCs+VEGF组额叶皮层和海马区Aβ含量明显减少（P＜ 0.01）,海马区CD34 阳性细胞数更高（P ＜ 0.01）。结论 将EPCs+VEGF 移植入鼠脑内,可以发现小鼠的记忆能力增强,原因可能与促进新生血管的生成、Aβ 清除有关。     

补体C3d-p28对阿尔茨海默病DNA疫苗的免疫增强作用

目的探讨补体C3d-p28作为分子佐剂,在阿尔茨海默病DNA疫苗基因免疫中的作用。方法在第1、8、22、43、64、85、106、127天,将重组质粒p(Aβ3-10)10、p(Aβ3-10)10-C3d-p28.3和pcDNA3.1(+)肌肉注射于APP/PS1双转基因鼠后腿股四头肌内。疫苗接种前、自第2次注射开始每次接种后7天取鼠眶静脉血共8次,以ELISA法检测抗Aβ抗体的滴度和分型;第8次(最后1次)眶静脉取血后进行6d的Morris水迷宫实验,通过定位航行和空间探索实验评估小鼠空间学习记忆能力。水迷宫实验结束后处死小鼠,以ELISA法检测小鼠脾细胞培养上清液中白细胞介素4(IL-4)和干扰素γ(IFN-γ)水平,免疫组化染色法检测小鼠脑内Aβ斑的表达。结果 p(Aβ3-10)10-C3d-p28.3组抗Aβ抗体水平高于p(Aβ3-10)10组[(55.03±8.93)μg/mLvs.(27.32±7.69)μg/mL,t=-4.455,P0.05],p(Aβ3-10)10-C3d-p28.3组抗体类型主要是IgG1型[(50.64±6.96)μg/mL],明显高于p(Aβ3-10)10组[(14.15±3.16)μg/mL,P0.05]。与p(Aβ3-10)10组比较,p(Aβ3-10)10-C3dp28.3组Morris水迷宫实验平均逃避潜伏期变短、穿越平台次数和穿越平台所在象限停留的时间比例明显增多(均P0.05);脾细胞培养上清液中IL-4水平增高[(110.22±18.12)pg/mL vs.(170.12±22.16)pg/mL,P0.05]、IFN-γ水平减低[(800.12±80.11)pg/mL vs.(640.12±70.53)pg/mL,F=6.152,P0.05];脑内沉积的Aβ斑块明显减少(P0.05)。结论补体C3d-p28分子佐剂使p(Aβ3-10)10-C3d-p28.3抗Aβ抗体的产生增加、Th2型免疫反应增强,转基因鼠空间学习记忆能力提高。     

姜黄素对APP/PS1双转基因小鼠认知功能、炎症反应及海马区突触素表达的影响

目的 探讨姜黄素对APP/PS1双转基因小鼠认知功能、炎症反应及海马区突触素表达的影响。方法 60只6月龄APP/PS1双转基因雄性小鼠随机分为A组、B组和C组,各20只;A组采用姜黄素100mg/kg/d加入小鼠饲料喂养,B组采用姜黄素300mg/kg/d喂养,C组采用姜黄素600mg/kg/d喂养;3组均喂养6个月。治疗前、治疗3、6个月,采用Morris水迷宫实验评估小鼠认知功能,采用免疫吸附试验法检测尾静脉血血清白介素-6（IL-6）、肿瘤坏死因子-α（TNF-α）等炎症因子水平;治疗6个月,采用免疫组化染色法检测小鼠海马 CA1 区突触素表达情况。结果 姜黄素治疗3、6个月,3组小鼠认知功能明显改善（P<0.05）,血清IL-6、TNF-α水平明显降低（P<0.05）。与A组比较,B组和C组治疗3、6个月认知功能明显改善（P<0.05）,血清IL-6、TNF-α水平均明显降低（P<0.05）,海马CA1区突触素表达水平明显升高（P<0.05）。而B组与C组均无统计学差异（P>0.05）。结论 姜黄素有助于改善APP/PS1双转基因小鼠海马突触素表达,抑制小鼠炎症反应,改善小鼠认知功能。     

Expression of DeltaNp73 in hippocampus of APP/PS1 transgenic mice following GFP-BMSCs transplantation

Abstract

Objective: To study the effect of hippocampal bone marrow stromal cells (GFP-BMSCs) transplantation on spatial memory and DeltaNp73 expression in APP/PS1 transgenic mice.

Methods: Twelve APP/PS1 transgenic mice randomly received either 10 μl GFP-BMSCs suspension in medium (GFP-BMSCs transplantation group) or 10 μl complete medium (sham-operated group). Learning and memory function of mice in both groups were observed and tested in Morris water maze experiment at 2 weeks after surgery. Senile plaques and DeltaNp73 protein in hippocampuses were determined by immunohistochemistry and western blot at 3 weeks after surgery, respectively.

Results: APP/PS1 mice treated with BMSCs performed significantly better on the water maze test than those in sham-operated group (P<0·05). Immunohistochemistry showed that GFP-BMSCs distributed uniformly and the number of Alzheimer’s senile plaques reduced after transplantation. Western blot showed that quantified DeltaNp73 protein expression was significantly higher in BMSCs transplantation group when compared with sham-operated group (P<0·01).

Conclusions: Our results suggest that BMSCs transplatation could retard Alzheimer’s disease (AD) like pathology and upregulate DeltaNp73 expression in hippocampuses of APP/PS1 transgenic mice. GFP-BMSCs transplantation will be a potential treatment for AD.     

Reactive oxidative species enhance amyloid toxicity in APP/PS1 mouse neurons

Objective To investigate whether intracellular amyloid β (iAβ) induces toxicity in wild type (WT) and APP/PS1 mice, a mouse model of Alzheimer’s disease. Methods Different forms of Aβ aggregates were microinjected into cultured WT or APP/PS1 mouse hippocampal neurons. TUNEL staining was performed to examine neuronal cell death. Reactive oxidative species (ROS) were measured by MitoSOXTM Red mitochondrial superoxide indicator. Results Crude, monomer and protofibrilAβ induced more toxicity inAPP/PS1 neurons than in WT neurons. ROS are involved in mediating the vulnerability of APP/PS1 neurons to iAβ toxicity. Conclusion Oxidative stress may mediate cell death induced by iAβ in neurons.     

Alternations of central insulin‐like growth factor‐1 sensitivity in APP/PS1 transgenic mice and neuronal models

Although many post‐mortem studies have found evidence of central insulin resistance in Alzheimer's disease (AD) patients, results on changes of central insulin‐like growth factor‐1 (IGF‐1) signaling in the pathological process of AD remain controversial. In the present study, we observed the activation states of IGF‐1 downstream signaling in brain slices of transgenic mice carrying APPswe/PS1dE9 mutations (APP/PS1 mice) at both early and late stages (ex vivo) and further investigated the involvement of oligomeric β‐amyloid (Aβ) and Aβ‐enriched culture medium (CM) on IGF‐1 sensitivity employing neuronal models (in vitro). In 6‐ and 18‐month‐old APP/PS1 mice, the phosphorylations of IGF‐1 receptor (IGF‐1R) and Akt in response to IGF‐1 stimulation were significantly reduced in the hippocampal and cortical slices, whereas IGF‐1R protein expression and mRNA levels of IGF‐1 and IGF‐1R in the hippocampal slices were significantly higher than that in wild‐type mice. In agreement with these results, reduced IGF‐1 sensitivity was verified in APP and PS1 double stably transfected CHO cells; moreover, IGF‐1 stimulated phosphorylations of IGF‐1R and Akt were also markedly weakened by oligomeric Aβ or Aβ‐enriched CM posttreatment in CHO cells without APP/PS1‐transfected (K1 cells) and primary hippocampal neurons. These observations indicate that the impaired central IGF‐1 sensitivity at early and late stages of APP/PS1 transgenic mice might be attributable, at least partially, to the overproduced Aβ, especially the oligomeric Aβ. These findings may shed new light on the mechanisms underlying the defective IGF‐1 signaling in AD pathogenesis and provide important clues for AD drug discovery. © 2013 Wiley Periodicals, Inc.     

Non-cognitive behaviours in an APP/PS1 transgenic model of Alzheimer's disease

Alzheimer's disease (AD) is characterised by progressive cognitive impairment with neuropsychiatric symptoms such as anomalous motor behaviour, depression, anxiety, weight loss, irritability and agitation. The effect of hAPP and PS1 overexpression on cognition has been well characterised in a variety of transgenic mouse models, however, non-cognitive behaviours have not been considered as systematically. The non-cognitive behaviour of the hAPP/PS1 transgenic mouse model (TASTPM) was observed at ages spanning the rapid progression of amyloid neuropathology. TASTPM transgenic mice, of both genders, exhibited decreased spontaneous motor activity, disinhibition, increased frequency and duration of feeding bouts, reduced body weight and, by 10 months, increased activity over a 24h period. In addition to the aforementioned behaviours, male transgenic mice also displayed enhanced aggression relative to wildtype controls. These data reveal previously unreported disease relevant behavioural changes that demonstrate the value of measuring behaviour in APP/PS1 transgenic models. These behavioural readouts could be useful in screening putative drug treatments for AD.     

Synaptic fatigue is more pronounced in the APP/PS1 transgenic mouse model of Alzheimer's disease

To search for potential mechanism that might alter synaptic transmission following Abeta increase we have examined the presynaptic component of transmitter release. As parameters of synaptic transmission that might underlie presynaptic mechanisms, we have used paired-pulse facilitation (PPF), post-tetanic potentiation (PTP), and synaptic fatigue (SF) at the connection between the hippocampal Schaffer-collateral pathway and CA1 pyramidal neurons in approximately 5 month old double transgenic mice overexpressing the mutated form of amyloid precursor protein (APPK670N, M671L) and presenilin 1 (PS1M146V). While the presynaptic mechanisms of PPF and PTP were not compromised in the APP/PS1 mice, SF was more pronounced in the double transgenic animals. The percentage of the 40th fEPSP slope over the first during the tetanus was 18 -/+ 3% in APP/PS1 vs. 26 -/+ 2% in WT. Thus, it is likely that presynaptic mechanisms underlying SF but not PPF and PTP, may account for synaptic dysfunction in APP/PS1 mice.     

APP/PS1双转基因AD传代小鼠的基因型鉴定及其行为学分析

目的 对APP/PS1双转基因AD传代小鼠进行基因型鉴定, 观察其学习记忆功能.方法 PCR鉴定APP/PS1双转基因AD传代小鼠的基因表型, 采用水迷宫实验检测记忆功能.结果 9只APP/PS1双转基因AD传代小鼠基因组DNA中5只小鼠基因组DNA扩增出约350 bp大小条带,认为成功转入APP和PS1基因.APP/PS1双转基因AD小鼠的水迷宫潜伏期比对照组小鼠明显延长.结论 利用PCR扩增APP基因可对APP/PS1双转基因AD传代小鼠进行基因型鉴定, APP/PS1双转基因AD小鼠能够较好地模拟AD患者的临床表现, 为AD的研究提供有效的实验动物模型.     

Aged wild-type and APP, PS1, and APP + PS1 mice present similar deficits in associative learning and synaptic plasticity independent of amyloid load

Wild-type and single-transgenic (APP, PS1) and double-transgenic (APP + PS1) mice were studied at three different (3-, 12-, and 18-month-old) age periods. Transgenic mice had reflex eyelid responses like those of controls, but only 3-month-old mice were able to fully acquire conditioned eyeblinks, using a trace paradigm, whilst 12-month-old wild-type and transgenic mice presented intermediate values, and 18-month-old wild-type and transgenic mice were unable to acquire this type of associative learning. 18-month-old wild-type and transgenic mice presented a normal synaptic activation of CA1 pyramidal cells by the stimulation of Schaffer collaterals, but they did not show any activity-dependent potentiation of the CA3–CA1 synapse across conditioning sessions, as was shown by 3-month-old wild-type mice. Moreover, 18-month-old wild-type and transgenic mice presented a noticeable deficit in long-term potentiation evoked in vivo at the hippocampal CA3–CA1 synapse. The 18-month-old wild-type and transgenic mice also presented a significant deficit in prepulse inhibition as compared with 3-month-old controls. Except for results collected by prepulse inhibition, the above-mentioned deficits were not related with the presence of amyloid β deposits. Thus, learning and memory deficits observed in aged wild-type and transgenic mice are not directly related to the genetic manipulations or to the presence of amyloid plaques.     

Sensorimotor gating and memory deficits in an APP/PS1 double transgenic mouse model of Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disorder associated with cognitive deterioration and neuropsychiatric symptoms. Sensorimotor gating deficit has been identified in neuropsychiatric diseases. The aim of the present study was to evaluate the possible sensorimotor gating deficit and its correlation to memory impairment and cerebral β-amyloid (Aβ) plaque deposits in an amyloid precursor protein (APP)/presenilin-1 (PS1) double transgenic mouse model of AD. The sensorimotor gating in 3-, 7- and-22-month-old non-transgenic and transgenic mice was evaluated in a prepulse inhibition (PPI) task. Results revealed that the PPI was lower in the 7- and 22-month-old transgenic mice compared with the age-matched control, while the response to startle pulse-alone in the transgenic and non-transgenic mice was comparable. Congo red staining showed that Aβ neuropathology of transgenic mice aggravated with age, and the 3-month-old transgenic mice started to have minimum brain Aβ plaques, corresponding to the early stage of AD phenotype. Furthermore, memory impairment in the 7-month-old transgenic mice was detected in a water maze test. These results suggest that the sensorimotor gating is impaired with the progressing of AD phenotype, and its deficit may be correlated to cerebral Aβ neuropathology and memory impairment in the APP/PS1 transgenic mouse model of AD.     

Characterization of amyloid deposition in the APPswe/PS1dE9 mouse model of Alzheimer disease

Transgenic mice carrying disease-linked forms of genes associated with Alzheimer disease often demonstrate deposition of the beta-amyloid as senile plaques and cerebral amyloid angiopathy. We have characterized the natural history of beta-amyloid deposition in APPswe/PS1dE9 mice, a particularly aggressive transgenic mouse model generated with mutant transgenes for APP (APPswe: KM594/5NL) and PS1 (dE9: deletion of exon 9). Ex vivo histochemistry showed Abeta deposition by 4 months with a progressive increase in plaque number up to 12 months and a similar increase of Abeta levels. In vivo multiphoton microscopy at weekly intervals showed increasing beta-amyloid deposition as CAA and plaques. Although first appearing at an early age, CAA progressed at a significantly slower rate than in the Tg2576 mice. The consistent and early onset of beta-amyloid accumulation in the APPswe/PS1dE9 model confirms its utility for studies of biochemical and pathological mechanisms underlying beta-amyloid deposition, as well as exploring new therapeutic treatments.     

小檗碱对三转基因阿尔茨海默病小鼠的学习记忆和海马PSD95突触相关蛋白表达水平的影响

目的 探讨小檗碱(BBR)对三转基因阿尔茨海默病(AD)小鼠的学习记忆及海马组织PSD95突触蛋白表达水平的影响。方法 将30只三转基因(APP/Tau/PS1)AD小鼠按随机数字表法分成3组,即AD对照组、AD+25 mgBBR组、AD+50 mgBBR,每组各10只,后2组以灌胃方式且剂量分别为25 mg·kg^-1·d^-1、50 mg·kg^-1·d^-1,对照组给予等剂量生理盐水连续3个月灌胃处理; 采用Morris水迷宫方法探测各组AD小鼠行为学改变、空间记忆及探索情况; 免疫荧光染色检测各组小鼠海马组织突触后致密蛋白95(PSD95)阳性表达水平; Western blotting(WB)法检测各组三转基因AD小鼠海马脑组织PSD95蛋白、磷酸化蛋白激酶B(p-Akt)和磷酸化雷帕霉素靶蛋白(p-mTOR)表达水平及微管相关蛋白轻链3-Ⅱ(LC3-Ⅱ)自噬水平。结果 AD+25 mgBBR组的逃避潜伏期的学习记忆能力、免疫荧光PSD95表达水平以及PSD995、LC3-Ⅱ、p-Akt、p-mTOR蛋白表达水平与AD对照组比较均有明显差异(P<0.05); AD+50 mgBBR组逃避潜伏期的学习记忆能力、免疫荧光PSD95表达水平以及LC3-Ⅱ、p-Akt、p-mTOR表达水平与AD对照组比较差异均更明显(P<0.05,P<0.01)。结论 应用50 mg小檗碱能较好改善三转基因AD小鼠的学习记忆、空间探索能力,其机制可能是通过增加自噬水平LC3-Ⅱ调控Akt/mTOR信号通路,增加突触蛋白PSD95的表达水平及突触数量,以改善AD相关临床症状。