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目的 探究不同剂量橙皮素(hesperetin)早期干预对APPswe/PS1dE9双转基因小鼠学习记忆能力、β-淀粉样蛋白(1-42)(amyloidβ-protein1-42,Aβ42)及Aβ降解酶脑啡肽酶(neprilysin,NEP)活性的影响.方法 设立三月龄C57BL/6J野生型小鼠为对照组(0.5%CMC-Na),三月龄APPswe/PS1dE9双转基因小鼠分别为模型组、橙皮素低、中、高剂量组(0、20、40、80mg/kg/d),灌胃1次/d,连续6个月.采用Morris水迷宫行为学实验观察小鼠的学习记忆能力;HE染色观察小鼠海马神经元形态;ELISA法检测小鼠血清中Aβ42含量;蛋白印迹法(Western Blot)检测小鼠脑组织Aβ42、脑啡肽酶(N E P)的表达.结果 与对照组相比,模型组小鼠寻找平台潜伏期明显延长(P<0.05),穿越平台次数减少(P<0.05),海马C A1区神经元有明显损伤,血清中Aβ42含量明显增加(P<0.05),脑组织中Aβ42含量明显增加(P<0.01)、N E P含量无明显差异;与模型组相比,橙皮素低、中、高剂量组小鼠潜伏期明显缩短(P<0.01),穿越平台次数增加(P<0.01),海马C A1区神经元形态结构有明显改善,血清中Aβ42含量明显降低(P<0.01),脑组织中Aβ42含量明显降低(P<0.01)、橙皮素中、高剂量组N E P含量明显升高(P<0.01).结论 橙皮素早期干预能明显改善APPswe/PS1dE9双转基因小鼠学习记忆能力和海马CA1区神经元损伤,其机制可能与提高NEP活性,增强Aβ42代谢有关. 相似文献
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目的:观察吸入麻醉药异氟醚对转APP基因小鼠脑内海马神经元蛋白质损伤和蛋白聚集的影响,并探讨海藻糖对异氟醚诱导的神经毒性的干预作用。方法:60只12月龄转APP基因小鼠随机分为对照组、异氟醚组(Iso组)和海藻糖组(Tre组),每组20只。对照组小鼠不给予任何药物,将其置于持续通入2 L·min-1氧气的麻醉箱中2h;Iso组和Tre组小鼠于麻醉前30 min分别经腹腔注射2 mL生理盐水或海藻糖(400 μg·kg-1)稀释液,然后给予1.4%异氟醚吸入麻醉2 h。麻醉后6 h 取小鼠海马组织制备脑组织匀浆,应用 DCFH-DA荧光法检测小鼠海马组织中活性氧(ROS)水平;麻醉后24 h应用免疫组织化学法和Western blotting法检测小鼠海马组织中蛋白羰基化合物、硝基化酪氨酸和β-淀粉样蛋白(Aβ)1-42蛋白表达水平,应用透射电镜检测海马神经元中蛋白聚集物的形成,应用TUNEL染色法观察小鼠海马组织中神经元凋亡率。结果:与对照组比较,Iso组小鼠海马组织中ROS水平、氧化蛋白羰基化合物、硝基化酪氨酸、Aβ1-42蛋白表达水平和神经元凋亡率均明显增加(P < 0.05);与Iso组比较,Tre组小鼠海马组织中ROS水平、氧化蛋白羰基化合物、硝基化酪氨酸、Aβ1-42蛋白表达水平和神经元凋亡率均明显降低(P < 0.05)。结论:异氟醚能诱导转APP基因小鼠海马神经元蛋白质损伤和蛋白聚集,加剧氧化应激反应,增加脑内海马神经元凋亡,海藻糖能够拮抗异氟醚诱导的神经毒性。 相似文献
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目的:探讨丹皮酚对血管性认知障碍(VCI)小鼠认知功能及海马神经元损伤的影响。方法:雄性C57BL/6小鼠60只,随机分为假手术(Sham)组、模型(VCI)组、丹皮酚(Pae)低、中、高剂量治疗组,每组12只。采用双侧颈总动脉结扎(2VO)制备小鼠反复缺血再灌注VCI模型,Morris水迷宫检测小鼠的认知功能,尼氏染色观察小鼠海马神经元的形态学变化,比色法检测海马SOD活性、MDA和NO含量的变化。结果:VCI小鼠认知功能下降(P〈0.01),海马CA1区神经元变性坏死,MDA和NO含量增加,SOD活性降低(P〈0.01);丹皮酚中、高剂量治疗可显著提高VCI小鼠的学习记忆能力,减少VCI所致的海马CA1区神经元死亡,并降低MDA和NO含量,升高SOD活性(P〈0.05或P〈0.01)。结论:丹皮酚可有效增强VCI小鼠的认知功能,并改善海马神经元病理改变,可能与其抗氧化应激有关。 相似文献
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目的 探讨分析乌灵菌粉对APPswe/PS1dE9双转基因阿尔兹海默病模型小鼠认知功能、Aβ1-42和p-Tau的影响。 方法 APPswe/PS1dE9双转基因小鼠20只,随机分成2组,每组10只,雌雄各半,即疾病模型组、乌灵菌粉组[剂量为100 mg/(kg·d)];C57BL/6品系的正常小鼠10只作为健康对照组,雌雄各半。乌灵菌粉组灌胃给药共30 d,疾病模型组和健康对照组同期给予相同体积生理盐水代替,正常喂食。3组小鼠先后进行Morris水迷宫实验、定位航行实验和空间搜索实验。在末次给药1 h后,脱颈椎处死各组小鼠,采用酶联免疫吸附方法(ELISA)检测3组Aβ1-42、p-Tau蛋白在小鼠海马中的含量。 结果 ①与健康对照组比较,乌灵菌粉组在逃避潜伏期、目标象限游泳时间、有效区停留时间和经过平台次数均显著增加(均P<0.01);与疾病模型组比较,乌灵菌粉组在逃避潜伏期、目标象限游泳时间、有效区停留时间和经过平台次数均显著下降(均P<0.05)。②与健康对照组比较,乌灵菌粉组小鼠海马中的Aβ1-42含量和p-Tau蛋白均显著增加(均P<0.01);与疾病模型组比较,乌灵菌粉组小鼠海马中的Aβ1-42含量显著降低(P<0.01)。 结论 乌灵菌粉能够改善APPswe/PS1dE9双转基因阿尔兹海默病模型小鼠记忆和学习能力,可能是通过减少小鼠海马中Aβ1-42含量来影响Aβ聚集体的形成,从而减少老年斑的生成。 相似文献
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目的 构建一种能够进入脑组织且靶向β淀粉样蛋白(β-amyloid,Aβ)的表面修饰多肽序列PTLHTHNRRRRR(简称RD2肽)的纳米递释系统.选择荷载表没食子儿茶素没食子酸酯(epigallocatechin-3-gallate,EGCG),以验证该靶向递释系统对阿尔茨海默病(Alzheimer's diseas... 相似文献
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Selective deletion of dnmts in excitatory neurons impairs recognition memory and synaptic function in hippocampal network of adult mice
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Objective: DNA methylation is one of the most important epigenetic modulation, which is catalyzed primarily by three methyltransferases, DNMT1, DNMT3a and DNMT3b. The aim of our study is to investigate the modulatory effect of DNMTs on hippocampus-dependent memory formation, and to explore the underlying molecular, cellular and synaptic mechanisms. Methods: Dnmt1, 3a and 3b were selectively deleted in the CA1 region of dorsal hippocampus by Cre/LoxP recombinase systerm, either with virus-mediated Cre expression in CA1 of Dnmtsflox/flox mice or conditional αCaMKII-Cre; Dnmtsflox/flox mice. Hippocampus-dependent and hippocampus-independent memory performance were evaluated in adult KO and control mice. RNA-seq analysis was conducted to screen differential expression genes in the hippocampus after conditional Dnmts knockout. Real-time qPCR and Western blot analysis were used to confirm the differential expression. We also analyzed the alteration in DNA methylation by Whole Genome Bisulfite Sequencing. Neuronal excitability, synaptic transmission and plasticity were measured in CA1 pyramidal neurons of hippocampal slices. Finally, we checked whether virus-mediated shRNA expression in hippocampal CA1 could ameliorate abnormal synaptic function and memory deficit observed in αCaMKII-Cre; Dnmstflox/flox mice. Results: We found that both Dnmt1flox/floxDnmt3aflox/flox mice and Dnmt3bflox/flox mice receiving AAV-Cre virus infection into CA1 region displayed recognition memory deficit to object place, but normal memory to novel object. All mice showed similar performance in fear memory tests. Also, virus infection and Dnmts deletion did not changed anxiety- or depression-like behavior. The object place recognition memory deficit was also observed in both αCaMKII-Cre; Dnmt1flox/floxDnmt3aflox/flox mice and αCaMKII-Cre; Dnmt3bflox/flox mice. The Cre expression in αCaMKII-Cre mice was verified to be dominant in hippocampal CA1. RNA-seq based gene expression and followed real-time qPCR and western blot analysis confirmed significant upregulation of certain genes after Dnmts deletion in aCaMKII-expression excitatory neurons in the hippocampus. WGBS analysis showed differentiated DNA methylation in related genes. Normal basal synaptic transmission but impaired LTP was observed in SC-CA1 path of both αCaMKII-Cre; Dnmt1flox/floxDnmt3aflox/flox mice and αCaMKII-Cre; Dnmt3bflox/flox mice. AAV-virus mediated specific shRNA expression in CA1 region of dorsal hippocampus interfered upregulation of candidate genes, rescued abnormal synaptic function, and ameliorated object place cognition impairment in both αCaMKII-Cre;Dnmt1flox/floxDnmt3aflox/flox mice and αCaMKII-Cre;Dnmt3bflox/flox mice. Virus-mediated shRNA expression in CA1 region of dorsal hippocampus did not affect recognition memory to novel object. Conclusion: In conclusion, our findings suggest that Dnmts in CA1 excitatory neurons plays an important role in regulating synaptic function and hippocampus-dependent recognition memory process by control the expression of certain target genes. 相似文献
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目的 研究慢性甲基苯丙胺(methamphetamine,MA)成瘾小鼠神经突触可塑性基因的表达变化情况.方法 选用C57BL/6J小鼠,模拟人类药物成瘾模式,分段渐进性腹腔注射给药5 mg/kg、10 mg/kg或者生理盐水.选取小鼠的大脑皮质和海马组织,通过亚硫酸氢盐处理基因组DNA和甲基化特异性PCR(methy... 相似文献