丙戊酸钠对APP/PS1双重转基因AD模型小鼠脑内老年斑和神经元的影响

目的 探讨丙戊酸钠 (valproic acid sodium salt,VPA)处理对淀粉样蛋白前体蛋白(β-amyloid precursor protein,APP)/早老素1(presenilin1,PS1)双重转基因阿尔茨海默病(Alzheimer's disease,AD)模型小鼠是否发挥神经保护作用.方法 对APP/PS1双重转基因AD模型种鼠交配后产下的子代进行基因分型,运用VPA 30 mg/(kg·d)和等量生理盐水腹腔注射APP/PS1双重转基因小鼠4周.药物处理后采用免疫组化、甲硫素S染色检测VPA对老年斑(senile plapues,SP)的影响,用Nissl染色、Tunel染色观察脑内神经元的变化,并采用ELISA定量检测小鼠脑内β-淀粉样蛋白(amyloid β peptide,Aβ)水平.结果 免疫组化及甲硫素S染色结果显示:VPA治疗组较生理盐水组的小鼠大脑皮质及海马区域的老年斑数量明显减少(t ＝ 7.78,P ＜ 0.01).Nissl染色发现VPA治疗组小鼠皮质及海马内的神经元数目较生理盐水组增加;Tunel染色显示VPA治疗组小鼠脑内凋亡神经元明显减少(t ＝ 5.95,P ＜ 0.01);ELISA结果提示VPA治疗组小鼠脑内Aβ40(t ＝ 4.23,P ＜ 0.01)和Aβ42(t ＝ 7.51,P ＜ 0.01)水平显著低于对照组.结论 VPA处理能显著减少AD模型小鼠减少脑内Aβ的沉积和老年斑的形成,通过减少神经元的凋亡来增加神经元的数量.     

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。     

白桦脂醇对APP/PS1双转基因痴呆模型小鼠认知及海马突触功能相关蛋白表达的影响

目的 探讨白桦脂醇对阿尔茨海默病（AD）小鼠的学习记忆功能的干预作用及海马突触功能相关蛋白表达的影响,为探索治疗AD提供新的可能。方法 采用白桦脂醇干预APP/PS1双转基因痴呆模型小鼠,将小鼠随机分为模型组、药物高剂量组和低剂量组,C57BL/6J健康小鼠为对照组。通过行为学观察学习记忆能力、在体电生理记录海马神经元的生物电、TUNEL法检测神经元凋亡、Realtime PCR法检测PSD-95和Synapsin-I水平。结果 水迷宫检测结果发现白桦脂醇能改善模型小鼠认知功能障碍;电生理检测AD模型组长时程增强（LTP）幅值低于对照组,经过白桦脂醇干预治疗后,白桦脂醇各组LTP幅值较AD模型组升高;AD模型组神经元凋亡率显著高于对照组,经过白桦脂醇干预治疗后凋亡率下降;AD小鼠模型海马区PSD-95和Synapsin-I表达下降,但经白桦脂醇干预后其表达上升。结论 白桦脂醇通过使海马PSD-95和Synapsin-I的表达增加,发挥对APP/PS1双转基因痴呆模型小鼠认知功能的保护,使海马长时程增强。     

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。     

6月龄野生型和APP/PS1转基因小鼠海马和皮层神经递质代谢组学研究

目的 探讨 6 月龄 APP/PS1 转基因小鼠相较于同月龄野生型小鼠海马和皮层组织神经递 质代谢物的变化。方法 选取健康雌性 6 月龄野生型和 APP/PS1 转基因小鼠各 8 只,3 只进行刚果红实 验,5 只利用超高效液相色谱串联质谱方法分析海马和皮层组织中神经递质代谢物的含量。在正交偏 最小二乘判别分析（OPLS-DA）模型主成分的差异权重贡献值（VIP）≥1的基础上,以独立样本t检验P＜0.05 或差异倍数（FC）值≥ 1.2 或 FC 值≤ 0.8,筛选组间差异代谢物。结果 6 月龄 APP/PS1 转基因小鼠海马 和皮层组织中出现 β 淀粉样蛋白沉积;两组小鼠的海马和皮层代谢轮廓呈现分离趋势。在小鼠海马 中鉴定出 17 种差异代谢物,分别为肾上腺素、去甲肾上腺素、左旋多巴、多巴胺、3,4- 二羟基苯乙酸酯 （DOPAC）、3,4- 二羟苯基二醇、3,4- 二羟基扁桃酸、甲氧基去甲肾上腺素（NMN）、4- 羟基 -3- 甲氧基苯 乙二醇（MHPG）、4- 羟基 -3- 甲氧基 - 扁桃酸 / 高香草酸（HVA）、谷氨酰胺、谷氨酸、γ- 氨基丁酸、5- 羟 色胺（5-HT）、羟基吲哚乙酸（5-HIAA）、鸟氨酸、酪胺;在小鼠皮层中鉴定出 12 种差异代谢物,分别为多巴 胺、DOPAC、NMN、3- 甲氧酪胺、MHPG、HVA、5-HT、5-HIAA、乙醇胺、L- 酪氨酸、L- 苯丙氨酸、苏氨酸。 结论 APP/PS1 转基因小鼠海马和皮层神经递质代谢种类趋势变化不同,可能作为 APP/PS1 转基因小 鼠认知功能障碍早期病理改变的靶点。     

黄连解毒汤对APP/PS1双转基因阿尔茨海默病模型小鼠脑组织的保护

Huanglian Jiedu decoction(HLJDD) has been shown to improve cerebral blood flow,and reduce lipid peroxidation damage to the brain and its energy metabolism.The present study was designed to observe the cerebroprotective effect of HLJDD on an Alzheimer’s disease rodent model,prese-nilin-1/amyloid protein precursor double transgenic mice.HLJDD reduced serum interleukin-6 and interleukin-1β levels,decreased β-amyloid precursor protein gene and senile plaque expression,resisted oxidation,and reduced free radical-induced injury,thereby improving the learning and memory of these mice.Moreover,HLJDD at 433 mg/kg per day exhibited better effects compared with that at 865 or 216 mg/kg per day,and donepezil hydrochloride at 30 mg/kg per day.Thus,these results suggest that HLJDD may have protective effects against Alzheimer’s disease.     

黄连解毒汤对APP/PS1双转基因阿尔茨海默病小鼠脑组织自由基代谢及IL-6、IL-1β含量的影响

目的观察黄连解毒汤(HLJDT)对阿尔茨海默病(Alzhemer’s disease,AD)模型小鼠自由基代谢及炎性细胞因子(IL-6,IL-1β)含量的影响,并探讨其可能治疗机制。方法采用APP/PS1双转基因AD小鼠模型,并随机分为模型对照组(CMC组)、阳性对照组(盐酸多奈哌齐组)、HLJDT大中小剂量组,每日予以相应药物灌胃治疗后检测脑组织中自由基代谢指标(SOD、MDA),并应用ELISA法检测炎性细胞因子(IL-6,IL-1β)含量。结果 HLJDT各剂量组均能明显提高SOD活性,降低MDA含量(P<0.01);盐酸多奈哌齐组及HLJDT各剂量组均显著降低IL-6含量(P<0.01);HLJDT小剂量组IL-1β含量低于CMC组,但HLJDT各剂量组及盐酸多奈哌齐组与模型对照组(CMC组)比较均无统计学差别(P>0.05)。结论 HLJDT治疗AD的机制可能与提高抗氧化能力,减轻炎症反应有关。     

Dab2调控阿尔茨海默病小鼠模型海马内TGF-β1/SMADs信号传导并减轻其脑损伤

目的研究Dab2蛋白对阿尔茨海默病疾病模型中TGF-β1/SMADs信号通路的调节作用以及其对阿尔茨海默病小鼠脑损伤的影响。方法 24只APP/PS1双转基因小鼠随机分为AD组、Vector组和Dab2组,每组8只,并将10只阴性对照小鼠作为对照组(Control)。对照组不做任何处理;饲养1个月后,AD组小鼠经双侧海马注射生理盐水,Dab2组小鼠双侧海马注射Dab2腺相关病毒质粒,Vector组小鼠双侧海马注射阴性对照质粒。所有小鼠于鼠龄9个月时进行行为学检测。10月龄时处死ELISA法检测脑组织中Aβ含量;Western blot检测海马中Dab2、TβRII和p-SMAD2/3的表达。结果 Dab2腺相关病毒质粒可在小鼠海马内高效表达Dab2。Dab2组小鼠海马组织中TβRII、p-SMAD2和p-SMAD3含量明显高于其阴性对照Vector组。Dab2组小鼠海马内Aβ含量明显低于Vector组,并且行为学评分明显高于Vector组小鼠。结论 Dab2过表达可通过上调TGF-β1/SMADs信号通路的传导,减轻阿尔茨海默病小鼠海马内Aβ的含量并改善其神经功能。     

黄连解毒汤对APP/PS1双转基因AD小鼠脑组织IL-6I、L-1β水平及SP、NFTs数量的干预作用

目的通过观察黄连解毒汤对APP/PS1双转基因阿尔茨海默病(AD)小鼠脑组织炎性细胞因子白细胞介素-6(IL-6)、白细胞介素-1β(IL-1β)水平及海马区老年斑(SP)、神经原纤维缠结(NFTs)数量的影响,探讨黄连解毒汤治疗AD的可能机制,以及其与西药盐酸多奈哌齐的疗效比较。方法 3月龄雄性SPF级APP/PS1双转基因AD小鼠分别经盐酸多奈哌齐或黄连解毒汤大、中、小剂量灌胃7个月后,应用酶联免疫吸附法(ELISA)检测其脑组织中炎性细胞因子IL-6I、L-1β水平,免疫荧光染色法检测小鼠海马区SP及NFTs数量并观察神经细胞核病理学变化,并进行分析。结果与模型溶剂对照组比较,盐酸多奈哌齐组及中药各剂量组IL-6水平均显著降低、神经细胞核病变发生率(PNND)均显著减低(P<0.01),SP数量均减少(P<0.01、P<0.01、P<0.01、P<0.05),NFTs形成均减少(P<0.05)。与盐酸多奈哌齐组比较,中药大、中、小剂量组IL-6水平均降低(P<0.05、P<0.01、P<0.05),中药中剂量组SP数量减少(P<0.05)、NFTs形成减少(P<0.01),PNND减低(P<0.01)。中药大、中剂量组较小剂量组SP数量减少(均P<0.01);NFTs形成大剂量组较中剂量组增多(P<0.05),中剂量组较小剂量组减少(P<0.01);大剂量组较中、小剂量组PNND增高(P<0.01、P<0.05),中剂量组较小剂量组PNND减少(P<0.01)。中药各剂量组间IL-6水平比较、各实验组组间IL-1β水平比较无统计学差异(均P>0.05)。结论中药黄连解毒汤同盐酸多奈哌齐均具有神经细胞保护作用,但其疗效可能优于盐酸多奈哌齐。     

Abeta levels in serum,CSF and brain,and cognitive deficits in APP + PS1 transgenic mice

We compared beta-amyloid peptide (Abeta) levels in the serum, CSF and brain (hippocampus) and correlated these with spatial learning in APP+PS1 transgenic mice. Compared with non-transgenic littermates, male 14-month-old APP + PS1 mice were impaired in spatial learning in the water maze. Among the APP + PS1 mice, only the hippocampal insoluble Abeta42 level correlated with spatial memory (r = -0.44). The levels of insoluble Abeta40 and Abeta42 were highly correlated (r = 0.92), and also correlated with soluble hippocampal Abeta42 (r = 0.64/0.69), which further correlated with the CSF Abeta42 (r = 0.52). None of these parameters correlated with serum Abeta40 levels. These findings support the role of insoluble Abeta42 in memory dysfunction and suggest a model with several pools (insoluble, extracellular soluble, CSF) of Abeta being in partial equilibrium with each other.     

APP/PS1KI bigenic mice develop early synaptic deficits and hippocampus atrophy

Abeta accumulation has an important function in the etiology of Alzheimer’s disease (AD) with its typical clinical symptoms, like memory impairment and changes in personality. However, the mode of this toxic activity is still a matter of scientific debate. We used the APP/PS1KI mouse model for AD, because it is the only model so far which develops 50% hippocampal CA1 neuron loss at the age of 1 year. Previously, we have shown that this model develops severe learning deficits occurring much earlier at the age of 6 months. This observation prompted us to study the anatomical and cellular basis at this time point in more detail. In the current report, we observed that at 6 months of age there is already a 33% CA1 neuron loss and an 18% atrophy of the hippocampus, together with a drastic reduction of long-term potentiation and disrupted paired pulse facilitation. Interestingly, at 4 months of age, there was no long-term potentiation deficit in CA1. This was accompanied by reduced levels of pre- and post-synaptic markers. We also observed that intraneuronal and total amount of different Abeta peptides including N-modified, fibrillar and oligomeric Abeta species increased and coincided well with CA1 neuron loss. Overall, these data provide the basis for the observed robust working memory deficits in this mouse model for AD at 6 months of age. H. Breyhan, O. Wirths and K. Duan contributed equally to this work.     

Dab2 attenuates brain injury in APP/PS1 mice via targeting transforming growth factor-beta/SMAD signaling简

Transforming growth factor-beta(TGF-β)type II receptor(TβRII)levels are extremely low in the brain tissue of patients with Alzheimer’s disease.This receptor inhibits TGF-β1/SMAD signaling and thereby aggravates amyolid-beta deposition and neuronal injury.Dab2,a specific adapter protein,protects TβRII from degradation and ensures the effective conduction of TGF-β1/SMAD signaling.In this study,we used an adenoviral vector to overexpress the Dab2 gene in the mouse hippocampus and investigated the regulatory effect of Dab2 protein on TGF-β1/SMAD signaling in a mouse model of Alzheimer’s disease,and the potential neuroprotective effect.The results showed that the TβRII level was lower in APP/PS1 mouse hippocampus than in normal mouse hippocampus.After Dab2 expression,hippocampal TβRII and p-SMAD2/3 levels were significantly increased,while amyloid-beta deposition,microglia activation,tumor necrosis factor-βand interleulin-6 levels and neuronal loss were significantly attenuated in APP/PS1 mouse brain tissue.These results suggest that Dab2 can exhibit neuroprotective effects in Alzheimer’s disease by regulating TGF-β1/SMAD signaling.     

BACE1 gene deletion prevents neuron loss and memory deficits in 5XFAD APP/PS1 transgenic mice

Evidence suggests that beta-amyloid (Abeta) peptide triggers a pathogenic cascade leading to neuronal loss in Alzheimer's disease (AD). However, the causal link between Abeta and neuron death in vivo remains unclear since most animal models fail to recapitulate the dramatic cell loss observed in AD. We have recently developed transgenic mice that overexpress human APP and PS1 with five familial AD mutations (5XFAD mice) and exhibit robust neuron death. Here, we demonstrate that genetic deletion of the beta-secretase (BACE1) not only abrogates Abeta generation and blocks amyloid deposition but also prevents neuron loss found in the cerebral cortex and subiculum, brain regions manifesting the most severe amyloidosis in 5XFAD mice. Importantly, BACE1 gene deletion also rescues memory deficits in 5XFAD mice. Our findings provide strong evidence that Abeta ultimately is responsible for neuron death in AD and validate the therapeutic potential of BACE1-inhibiting approaches for the treatment of AD.     

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.     

Lactate administration attenuates cognitive deficits following traumatic brain injury

Moderately head injured patients often suffer long term neurological sequelae. There is no therapy for brain trauma and current treatments aim only to minimize secondary damage. These secondary effects are often triggered by the inability to re-establish ionic homeostasis after injury, due to large energy demands. Recent reports have demonstrated that neurons are capable of utilizing lactate as an energy source, thus this report examines the usefulness of lactate administration in the attenuation of behavioural deficits following a moderate brain injury. Lactate infusion (i.v.) was started 30 min after lateral fluid percussion injury and continued for 3 h. Cognitive deficits were determined using the Morris water maze. Lactate infused injured animals demonstrated significantly less cognitive deficits than saline infused injured animals. Thus, lactate infusion attenuated the cognitive deficits normally observed in this model, and therefore may provide moderately head injured patients with a treatment to help ameliorate the sequelae.     

Progressive age-related development of Alzheimer-like pathology in APP/PS1 mice

Increasing evidence points to synaptic plasticity impairment as one of the first events in Alzheimer's disease (AD). However, studies on synaptic dysfunction in different transgenic AD models that overexpress familial AD mutant forms of amyloid precursor protein (APP) and/or presenilin (PS) have provided conflicting results. Both long-term potentiation (LTP) and basal synaptic transmission (BST) have been found to be both unchanged and altered in different models and under differing experimental conditions. Because of their more robust amyloid-beta (Abeta) deposition, double transgenic mice currently are used by several laboratories as an AD model. Here, we report that mice overexpressing APP (K670N:M671L) together with PS1 (M146L) have abnormal LTP as early as 3 months of age. Interestingly, reduced LTP paralleled plaque appearance and increased Abeta levels and abnormal short-term memory (working memory). BST and long-term memory (reference memory) are impaired only later (approximately 6 months) as amyloid burden increases. Abeta pathology across different ages did not correlate with synaptic and cognitive deficits, suggesting that Abeta levels are not a marker of memory decline. In contrast, progression of LTP impairment correlated with the deterioration of working memory, suggesting that percentage of potentiation might be an indicator of the cognitive decline and disease progression in the APP/PS1 mice.     

规律性运动对APP／PS1小鼠学习记忆能力的影响

目的探讨有规律的适宜运动对AD模型小鼠的学习记忆能力的影响。方法雌性C57BL／c野生型小鼠及APP／PSl转基因小鼠,经过6个月规律性运动后,测定小鼠α-分泌酶／ADAMl0活性,A8及学习记忆行为学变化。结果规律性运动6个月不仅大大提高了在野生型小鼠的学习记忆行为,而且还改善AD转基因小鼠在学习和记忆障碍,提高了在野生型小鼠及AD转基因小鼠的α-分泌酶活性,抑制Aβ40和Aβ42的产生。结论提示规律性运动可能通过增加α-分泌酶活性,抑制脑内Aβ的生成量,参与了运动对学习记忆的作用。