脂肪因子chemerin在饮食和运动调控小鼠骨骼肌脂质沉积中的作用

目的:探讨维甲酸受体应答基因2(retinoic acid receptor responder 2, Rarres2)编码的脂肪因子chemerin在饮食和运动调控小鼠骨骼肌脂质沉积中的作用。方法:将8周龄野生型(wild-type, WT)小鼠、脂肪特异性Rarres2基因敲除(adipose-specific Rarres2 gene knockout, adipo-Rarres2^-/-)小鼠和全身性Rarres2基因敲除(global Rarres2 gene knockout, Rarres2^-/-)小鼠随机分为普通饮食(normal diet, ND)组和高脂饮食(high-fat diet,HFD)组,即ND+WT组、ND+adipo-Rarres2^-/-组、ND+Rarres2^-/-组、HFD+WT组、HFD+adipo-Rarres2^-/-组和HFD+Rarres2^-/-组,共6组,每组6只。此外,让HFD组的3种小鼠完成6周的中等强度跑...     

褪黑素对Ctnnd2敲除小鼠的自闭症样行为及突触相关蛋白的影响

目的:观察褪黑素（MT）对Ctnnd2基因敲除(Ctnnd2^-/-)小鼠自闭症样行为、丝裂原活化蛋白激酶（MEK）/细胞外信号调节蛋白激酶（ERK）通路蛋白和突触相关蛋白的影响。方法:将小鼠分为四组：野生型组（WT）、Ctnnd2基因敲除组(Ctnnd2^-/-)、Ctnnd2基因敲除+10 mg/kg褪黑素组(Ctnnd2^-/-+10 mg/kg MT)及Ctnnd2基因敲除+50 mg/kg褪黑素组(Ctnnd2^-/-+50 mg/kg MT)。不同剂量MT给出生21 d Ctnnd2^-/-小鼠连续灌胃28 d,行为学实验评价小鼠的自闭症样行为，Western Blot检测MEK1/2、ERK1/2和突触素蛋白（Syn）的磷酸化水平以及突触后致密蛋白95（PSD95）的表达。接下来为了验证MT是否通过与MT-R结合进而上调体感皮层MEK/ERK通路和引起突触相关蛋白的变化，在Ctnnd2^-/-小鼠体感皮层局部微量注射褪黑素受体（MT-R）阻断剂，30 m...     

长期酒精暴露诱导胰岛素抵抗及视网膜微血管损伤：神经鞘磷脂的可能作用

目的 探讨长期酒精暴露诱导胰岛素抵抗对小鼠血视网膜屏障的损伤以及神经鞘磷脂(SM)可能的作用。 方法 选取神经鞘磷脂合成酶
2（SMS2）基因敲除(SMS2^-/-)和野生型(WT)小鼠76只,酒精暴露建立动物模型。用血糖仪测定血糖浓度,酶联免疫法(ELISA)测定血胰岛素浓
度,并计算胰岛素抵抗指数(HOMA-IR),利用免疫荧光染色、HE和电子显微镜观察血视网膜屏障的损伤。结果 长期酒精暴露引起小鼠胰岛素抵
抗 (P <0.05),并出现血视网膜屏障的损伤,如无细胞毛细血管数增多(P <0.05),星形胶质细胞数量减少(P <0.05),内皮细胞和周细胞线粒
体肿胀,嵴消失,基底膜欠清晰,呈剂量依赖性。和WT小鼠相比,SMS2^-/-小鼠胰岛素抵抗指数较小和血视网膜屏障损伤程度较轻(P<0.05),
提示SMS2^-/-小鼠有延缓胰岛素抵抗形成和减少血视网膜屏障损伤的作用。结论 长期酒精暴露可以诱导胰岛素抵抗,并造成血视网膜屏障损
伤,具有剂量依赖性;SMS2基因的缺失有延缓胰岛素抵抗的产生和减少血视网膜屏障损伤的作用。     

链脲佐菌素对APP/PS1转基因小鼠脑内糖原合成酶-3α活性的影响

目的观察链脲佐菌素(streptozotocin,STZ)诱导的实验性糖尿病对APP/PS1转基因小鼠脑组织中糖原合成酶-3α(GSK-3α)蛋白活性的影响。方法 3月龄APP/PS1转基因小鼠腹腔内注射STZ建立实验性糖尿病模型。使用电子天平和便携式血糖仪定期检测小鼠体重和血糖的变化。应用免疫组织化学方法和western blotting方法检测AD转基因小鼠脑组织中p-GSK-3α和GSK-3α的蛋白表达。结果动物饲养20W后,与APP/PS1转基因小鼠比较,STZ组转基因小鼠体重下降(P<0.05),血糖则明显升高(P<0.01),提示糖尿病模型诱导成功。Western blotting结果显示,STZ组APP/PS1转基因小鼠脑内p-GSK-3α蛋白表达水平较APP/PS1转基因小鼠明显降低(P<0.01),而总GSK-3α蛋白没有变化(P>0.05),两者的比值p-GSK-3α/GSK-3α下降49%(P<0.01)。免疫组化染色显示,STZ组转基因小鼠大脑皮层神经元内p-GSK-3α阳性表达明显低于转基因小鼠。结论 STZ上调APP/PS1转基因小鼠脑组织内GSK-3α蛋白活性。     

Nrf2敲除小鼠模型的构建与基因型鉴定

目的 构建并鉴定Nrf2敲除模型小鼠。方法 将引进一对雌雄杂合子(Nrf2^-/+)小鼠进行交配，繁育出F1代小鼠；将F1代小鼠中基因型为Nrf2^-/+的雌雄小鼠继续进行交配，获得F2代小鼠；小鼠5日龄时剪尾部组织提取DNA,用PCR和琼脂糖凝胶电泳进行基因型结果判定。提取Nrf2敲除小鼠肺组织蛋白质，用Western blot检测NRF2蛋白表达情况，佐证鉴定结果。结果 雌雄纯合子(Nrf2^-/-)基因敲除小鼠可继续交配，获得基因敲除纯合子小鼠；F1与F2代杂合子小鼠交配可获得3种基因型：野生型(Nrf2^+/+)、杂合子(Nrf2^+/-)、纯合子(Nrf2^-/-),用PCR成功鉴定出子代小鼠的基因型；Nrf2敲除小鼠肺组织的NRF2蛋白表达显著低于野生型(P<0.05)。结论 本研究成功繁育出Nrf2全身敲除模型小鼠，为进一步探讨NRF2的作用及其机制提供了新的实验工具。     

肺泡表面活性蛋白A调控Tfh亚群分化缓解哮喘气道炎症

目的 探究肺泡表面活性蛋白A(surfactant protein A,SP-A)能否通过调控滤泡辅助性T细胞(follicular helper T cell,Tfh)的分化参与调节哮喘病理过程。方法 6-8周的雌性野生型(wildtype,WT)及SP-A基因敲除Sp-a^-/-型C57BL/6J小鼠,利用鸡卵白蛋白(ovalbumin,OVA)和氢氧化铝免疫构建哮喘模型(WT哮喘小鼠:8只,Sp-a^-/-哮喘小鼠:8只),并分别设立磷酸盐缓冲液(phosphate buffer saline,PBS)处理的对照组(WT对照小鼠:6只,Sp-a^-/-对照小鼠:4只)。HE染色观察小鼠肺部病理改变,流式细胞术检测脾脏和纵隔淋巴结中Tfh细胞及其亚群的组成,Tfh亚群根据其胞内干扰素-γ(interferon-γ,IFN-γ)、白细胞介素(interleukin,IL)-17和IL-4的表达情况,分别定义为IFN-γ⁺Tfh、IL-17⁺Tfh和IL-4⁺Tfh细胞。酶联免疫吸附试验(enzyme linked immunosorbent assay,ELISA)用于检测支气管肺泡灌洗液(bronchoalveolar lavage fluid,BALF)中免疫球蛋白(immunoglobulin,Ig)E的水平。将T-B细胞共培养,检测培养体系中IgE抗体的水平。在体外,给予人肺泡表面活性蛋白A(human SP-A,hSP-A)处理并设立对照组,培养5 d后检测体系中Tfh亚群的分布情况。结果 OVA激发后小鼠BALF中和肺组织内有大量炎症细胞浸润,WT及Sp-a^-/-哮喘小鼠BALF中炎症细胞总数显著高于其相对应对照组小鼠[(11.38±1.43)×10⁴比(6.40±0.68)×10⁴,(14.38±1.52)×10⁴比(6.25±0.48)×10⁴,t值分别为2.61和3.64,P值均<0.05],差异具有统计学意义。另外,OVA激发后,WT和Sp-a^-/-哮喘小鼠BALF中IgE的水平明显高于其相应的对照组小鼠[(16.85±2.50)pg/mL比(4.94±2.01)pg/mL,(25.52±3.17)pg/mL比(8.05±2.90)pg/mL,t值分别为3.63和3.58,P值均<0.05)],且Sp-a^-/-哮喘小鼠BALF中IgE抗体的水平明显高于WT哮喘小鼠(t=2.20,P<0.05),差异具有统计学意义。进一步研究显示,Tfh亚群组成在哮喘模型的WT和Sp-a^-/-小鼠中存在不同,表现为Sp-a^-/-哮喘小鼠IL-4⁺Tfh细胞比例高于WT哮喘小鼠,IFN-γ⁺Tfh细胞比例降低,但差异并不具有统计学意义(P>0.05)。Tfh细胞的亚群组成发生变化,其中IL-4⁺Tfh比例与肺泡灌洗液中IgE水平呈正相关(r=0.50,P<0.05),而IFN-γ⁺Tfh比例与肺泡灌洗液中IgE水平呈负相关(r=-0.56,P<0.05)。脾脏中IFN-γ⁺Tfh/IL-4⁺Tfh的比值在Sp-a^-/-哮喘小鼠中显著低于WT小鼠(t=2.31,P<0.05),且与肺泡灌洗液中IgE呈负相关(r=-0.55,P<0.05)。T-B细胞共培养实验发现,Sp-a^-/-小鼠脾脏来源Tfh细胞具有更强的辅助B细胞合成IgE抗体的能力(t=3.18,P<0.05)。后续的体外T细胞刺激实验证实,hSP-A处理可以上调培养体系中IFN-γ⁺Tfh细胞比例与IFN-γ⁺Tfh/IL-4⁺Tfh的比值(t值分别为6.34和3.16,P值均<0.05),但并未明显改变IL-4⁺Tfh细胞比例(P>0.05)。结论异常的Tfh细胞亚群分布与哮喘的发生相关,SP-A可能通过稳定Tfh细胞亚群的分布,从而缓解哮喘气道炎症反应。     

激酶mTORC2在EAE模型中对致病性CD4+T细胞的调控作用

目的 研究mTORC2信号缺陷减轻EAE临床症状和其对致病性CD4⁺T细胞的调控机制。方法 通过MOG_35-55肽免疫分别诱导Rictor^fl/flCD4^cre(Rictor^-/-)和Rictor^fl/fl(WT)小鼠，记录其临床症状分数和体质量变化情况，应用流式细胞术检测致病性CD4⁺T细胞亚群的数目、过氧化脂质水平和线粒体来源的ROS水平。结果 Rictor^-/-小鼠中EAE临床症状比WT小鼠更轻，致病性CD4⁺T细胞更少，且这群细胞更易发生铁死亡。结论 mTORC2信号缺陷通过促使致病性CD4⁺T细胞发生铁死亡来减轻EAE的临床症状。     

长期酒精暴露引起小鼠胰岛素抵抗：神经酰胺的可能作用

目的 探讨长期酒精暴露与胰岛素敏感性之间的关系并探讨其相关的分子机制;观察神经酰胺在酒精引起胰岛素抵抗过程中的可能作用。 方法 建立C57BL/6J野生型（WT）小鼠和神经鞘磷脂合成酶2基因敲除（SMS₂^-/-）3月龄小鼠的长期酒精暴露模型,两基因型小鼠又分为对照组、中剂量酒精组和高剂量酒精组,共计90只。建模5个月后,用血糖仪测定小鼠空腹血糖值,用酶学法检测血清胰岛素浓度,并计算胰岛素抵抗指数。利用免疫荧光染色法观察各组小鼠海马CA1区胰岛素受体底物2（IRS2）阳性细胞表达情况,免疫印迹法检测小鼠海马组织IRS2蛋白的相对表达量。 结果 1.长期酒精暴露导致WT和SMS-/-2小鼠空腹血糖值和胰岛素抵抗指数升高,且具有剂量依赖性（P<0.05）;但SMS₂^-/-小鼠随着酒精剂量的增加胰岛素抵抗指数升高幅度较小。 2.免疫组织化学染色显示,酒精暴露诱导WT和SMS₂^-/-小鼠海马IRS2阳性细胞数降低,有剂量依赖性（P<0.05）;与相同处理条件的WT小鼠相比,酒精诱导SMS₂^-/-小鼠海马IRS2阳性细胞数降低增多（P<0.05）。 3.免疫印迹法检测各组间小鼠海马组织IRS2蛋白相对表达量与上述结果一致。 结论 长期酒精暴露可引起胰岛素抵抗,IRS2蛋白表达降低,且存在剂量依赖性,因此酒精导致IRS2表达下降可能是胰岛素抵抗的分子机制之一;神经酰胺可能参与酒精暴露诱导IRS2表达下降的过程,且有促进胰岛素抵抗形成的作用。     

E3蛋白泛素连接酶WWP1调控TLR4介导的炎症性肠病炎性聚集中的作用

目的 探讨E3蛋白泛素连接酶WWP1调控TLR4介导的炎症性肠病炎性聚集中的作用及机制。方法 构建髓系细胞中特异性敲除E3蛋白泛素连接酶WWP1基因的小鼠，检测WPP1基因是否被敲除，随后进行分组，分为WWP敲除组(WWP1^+/+)和WWP未敲除组(WWP1^-/-)，两组小鼠再分别喂养菊聚糖硫酸钠(DSS)建立炎症性肠病模型(DSS组)和喂养生理盐水(无菌水组)，每组小鼠共10只，喂养7 d，每天检测小鼠结肠炎的临床症状，结束后处死小鼠，测量结肠长度，评估小鼠结肠炎损伤情况，Elisa检测小鼠结肠黏膜组织炎性因子IL-6、IL-10、TNF-α水平，采用RT-qPCR和Western blot检测TLR4表达水平。同时使用基因沉默方法敲除RAW 264.7细胞的WWP1基因，使用LPS刺激构建结肠炎症情况下的巨噬细胞环境，检测WWP1⁺组与WWP1^-组细胞中IL-6、IL-10、TNF-α和TLR4、WWP1表达水平。结果 WWP1^+/+组和RAW264.7细胞沉默组中WWP1...     

敲除toll样受体4基因对小鼠实验性自身免疫性脑脊髓炎的影响

目的:研究toll样受体4（TLR4）在小鼠实验性自身免疫性脑脊髓炎（EAE）发病中的作用。方法:C57BL/6野生型（WT）和Tlr4敲除(Tlr4^-/-)小鼠注射髓鞘少突胶质细胞糖蛋白35-55(MOG_35-55)建立EAE模型。定期记录神经功能评分及体重变化;苏木素-伊红（HE）和劳克坚牢蓝（LFB）染色观察脊髓组织内炎症细胞浸润及髓鞘脱失情况;免疫荧光染色检测髓鞘碱性蛋白（MBP）的表达。结果:MOG_35-55免疫后,与WT组相比,Tlr4^-/-小鼠体重下降程度较轻、发病时间延迟、神经功能评分降低、炎性细胞浸润减少、髓鞘脱失减轻、MBP表达增加。结论:敲除Tlr4可减轻EAE小鼠的病理症状。     

淫黄葛复合剂对阿尔茨海默病小鼠行为学和海马解聚素金属蛋白酶10表达的影响

目的 探讨淫羊藿、黄芪、葛根有效组分复方对阿尔茨海默病（AD）模型小鼠行为学和海马CA3区解聚素金属蛋白酶10（ADAM10）表达的影响。方法 10月的雄性APPswe/PS1dE9双转基因模型小鼠30只随机分为复方组、模型组和去铁斯诺(DFX)组,10月龄的雄性C57BL/6 J小鼠10只作为正常对照组。用药结束后,采用Morris水迷宫检测各组小鼠学习记忆能力,并于水迷宫后取出小鼠的脑组织,应用免疫荧光、Real-time PCR和Western blotting方法检测各组小鼠海马CA3区ADAM10的表达。结果 水迷宫实验结果显示,与正常对照组小鼠相比,模型组小鼠的逃避潜伏期、游泳距离和游泳时间均明显延长(P＜0.05),穿越平台区域次数和平台区域停留时间明显减少(P＜0.05),首次穿越平台的逃避潜伏期明显延长(P＜0.05);与模型组小鼠相比,复方组和DFX组逃避潜伏期、游泳距离和游泳时间明显缩短(P＜0.05),穿越平台区域次数和平台区域停留时间明显增多(P＜0.05),首次穿越平台的逃避潜伏期明显缩短;复方组和DFX组相比,逃避潜伏期、游泳距离和游泳时间及跨台次数差异无显著性 (P＞0.05),穿越平台区域次数、平台区域停留时间和首次穿越平台的逃避潜伏期差异无显著性 (P＞0.05)。与正常对照组小鼠相比,模型组小鼠海马CA3区ADAM10的表达增高(P＜0.05);与模型组相比,复方组和DFX组小鼠海马CA3区DAM10的表达降低(P＜0.05);复方组和DFX组相比,ADAM10表达水平差异无显著性 (P＞0.05)。结论 应用淫羊藿、黄芪、葛根有效组分复方可以改善APPswe/PS1dE9双转基因AD模型小鼠的学习记忆能力,其机制可能与下调ADAM10的表达减少神经元的损伤和死亡有关。     

Seizure susceptibility and mortality in mice that over-express amyloid precursor protein

Alzheimer's disease and Fragile X syndrome both display synaptic phenotypes, and based on recent studies, likely share dendritic over expression of amyloid precursor protein (APP) and beta-amyloid (Abeta). In order to create a mouse model to specifically study the effects of APP and Abeta at synapses, we crossed Tg2576, which over-express human APP with the Swedish mutation (hAPPsw), with fmr-1 KO mice. The progeny, named FRAXAD, displayed increased mortality (23% by 30 days of age) compared to Tg2576 (3%) and WT and fmr-1 KO littermate controls (0%) consistent with a developmental defect. By 60 days of age, both the Tg2576 and FRAXAD mice approached a 40% mortality rate compared to 0% for WT and fmr-1 KO littermates. To understand the mechanism underlying increased mortality in APP over-expressing mice, we assessed seizure thresholds in response to pentylenetetrazol (PTZ). Both the Tg2576 and FRAXAD mice had a lower threshold to PTZ-induced seizures (average seizure score of >/=4.0) in comparison to nontransgenic littermates (average seizure score 1.9-2.9). Seizures are a major phenotype of AD, FXS, Down syndrome, autism and epilepsy, and these data suggested that developmental over-expression of dendritic APP or Abeta increased seizure susceptibility.     

Mitochondria are a direct site of A beta accumulation in Alzheimer's disease neurons: implications for free radical generation and oxidative damage in disease progression

Alzheimer's disease (AD) is a complex, neurodegenerative disease characterized by the impairment of cognitive function in elderly individuals. In a recent global gene expression study of APP transgenic mice, we found elevated expression of mitochondrial genes, which we hypothesize represents a compensatory response because of mitochondrial oxidative damage caused by the over-expression of mutant APP and/or amyloid beta (Abeta). We investigated this hypothesis in a series of experiments examining what forms of APP and Abeta localize to the mitochondria, and whether the presence of these species is associated with mitochondrial dysfunction and oxidative damage. Using immunoblotting, digitonin fractionation, immunofluorescence, and electron microscopy techniques, we found a relationship between mutant APP derivatives and mitochondria in brain slices from Tg2576 mice and in mouse neuroblastoma cells expressing mutant human APP. Further, to determine the functional relationship between mutant APP/Abeta and oxidative damage, we quantified Abeta levels, hydrogen peroxide production, cytochrome oxidase activity and carbonyl proteins in Tg2576 mice and age-matched wild-type (WT) littermates. Hydrogen peroxide levels were found to be significantly increased in Tg2576 mice when compared with age-matched WT littermates and directly correlated with levels of soluble Abeta in Tg2576 mice, suggesting that soluble Abeta may be responsible for the production of hydrogen peroxide in AD progression in Tg2576 mice. Cytochrome c oxidase activity was found to be decreased in Tg2576 mice when compared with age-matched WT littermates, suggesting that mutant APP and soluble Abeta impair mitochondrial metabolism in AD development and progression. An increase in hydrogen peroxide and a decrease in cytochrome oxidase activity were found in young Tg2576 mice, prior to the appearance of Abeta plaques. These findings suggest that early mitochondrially targeted therapeutic interventions may be effective in delaying AD progression in elderly individuals and in treating AD patients.     

SOD1 rescues cerebral endothelial dysfunction in mice overexpressing amyloid precursor protein

Peptides derived from proteolytic processing of the beta-amyloid precursor protein (APP), including the amyloid-beta peptide, are important for the pathogenesis of Alzheimer's dementia. We found that transgenic mice overexpressing APP have a profound and selective impairment in endothelium-dependent regulation of the neocortical microcirculation. Such endothelial dysfunction was not found in transgenic mice expressing both APP and superoxide dismutase-1 (SOD1) or in APP transgenics in which SOD was topically applied to the cerebral cortex. These cerebrovascular effects of peptides derived from APP processing may contribute to the alterations in cerebral blood flow and to neuronal dysfunction in Alzheimer's dementia.     

Social behavior in Fmr1 knockout mice carrying a human FMR1 transgene

Fragile X syndrome (FXS) results from the loss of expression of the fragile X mental retardation (FMR1) gene. Individuals affected by FXS experience many behavioral problems, including cognitive impairment, hyperactivity, social anxiety, and autistic-like behaviors. A mouse model of Fmr1 deficiency (Fmr1KO) exhibits several similar behavioral phenotypes, including alterations in social behavior. In an earlier study, Fmr1 knockout mice carrying a yeast-artificial chromosome (YAC) transgene that over-expresses normal human FMRP (KOYAC) showed a correction or overcorrection of some behavioral responses, such as hyperactivity and anxiety-related responses. This report presents results from a study examining transgenic rescue of abnormal social responses in Fmr1KO mice. Relative to their wild-type (WT) littermates, Fmr1KO mice made more active social approaches to standard C57BL/6 partner mice in a direct social interaction test, a result consistent with a previous study. KOYAC mice showed fewer active approaches to partners than the WT or Fmr1KO littermates, indicating correction of this phenotype. This finding expands the number of murine behavioral responses caused by Fmr1 deficiency and corrected by overexpression of human FMRP.     

阿尔茨海默病小鼠模型中骨髓间充质干细胞的神经分化

 目的：探讨淀粉样前体蛋白（APP）转基因小鼠（阿尔茨海默病小鼠模型）骨髓间充质干细胞（MSCs）的神经分化及其与参与调节干细胞分化的Notch1信号通路的关系,观察分化的骨髓间充质干细胞中自噬的变化。方法：实验分为APP转基因小鼠组（APP组）和野生型小鼠组（WT组）。采用β-巯基乙醇诱导小鼠MSCs分化为神经细胞;采用酶联免疫吸附法（ELISA）检测诱导后β淀粉样蛋白40（Aβ40）和42（Aβ42）的水平;采用免疫细胞化学染色法和Western blotting检测神经元特异性烯醇化酶（NSE）和微管相关蛋白2（MAP-2）的表达变化;Western blotting检测Notch1、Notch胞内域（NICD）和Hes5的水平。结果：与野生型小鼠相比,APP转基因小鼠的骨髓间充质干细胞具有更强的神经分化能力、更高的Aβ表达及更强的Notch1信号抑制。但是,自噬作为神经细胞存活和神经功能必不可少的条件,在分化后的APP 转基因小鼠来源的MSCs中受损。结论:过表达APP可能通过抑制Notch-1信号通路增强小鼠骨髓间充质干细胞神经分化的能力,而分化后的APP转基因小鼠MSCs出现自噬通路异常。     

Cognitive impairment and increased Aβ levels induced by paraquat exposure are attenuated by enhanced removal of mitochondrial H(2)O(2)

Pesticide exposure is a risk factor of Alzheimer's disease (AD). However, little is known about how pesticide exposure may promote AD pathogenesis. In this study, we investigated the effects of paraquat pesticide exposure on β-amyloid (Aβ) levels and cognition using wild-type (WT) mice and β-amyloid precursor protein (APP) transgenic mice. Our results showed that wild-type mice and APP transgenic mice after paraquat exposure had increased oxidative damage specifically in mitochondria of cerebral cortex and exhibited mitochondrial dysfunction. Moreover, the elevated mitochondrial damage was directly correlated with impaired associative learning and memory and increased Aβ levels in APP transgenic mice exposed to paraquat. Furthermore, overexpression of peroxiredoxin 3, a mitochondrial antioxidant defense enzyme important for H₂O₂ removal, protected against paraquat-induced mitochondrial damage and concomitantly improved cognition and decreased Aβ levels in APP transgenic mice. Therefore, our results demonstrate that mitochondrial damage is a key mechanism underlying cognitive impairment and elevated amyloidogenesis induced by paraquat and that enhanced removal of mitochondrial H₂O₂ could be an effective strategy to ameliorate AD pathogenesis induced by pesticide exposure.     

Identification of the Alzheimer's disease amyloid precursor protein (APP) and its homologue APLP2 as essential modulators of glucose and insulin homeostasis and growth

The amyloid precursor protein (APP), the source of the neurotoxic amyloid beta (A beta) peptide involved in Alzheimer's disease (AD), belongs to a conserved family of related proteins. In mammals, the APP family contains amyloid precursor-like protein 1 (APLP1) and amyloid precursor-like protein 2 (APLP2). Whilst a number of activities have been attributed to the APP family, an overall function has not been definitively established. While ablating either the APP or APLP2 gene in mice produces minimal phenotypic change, the combined knockout of these genes in mice causes postnatal mortality. Postnatal survival therefore requires a shared but unknown function of APP and APLP2. To investigate the biochemical basis for the postnatal lethality, plasma was analysed from double knockout mice (APP-/- APLP2-/-) 2 days before birth, at gestational day E17, and from mice at 12-16 h after birth. The postnatal double knockouts had 66% lower plasma glucose levels than their wild-type controls and 50% lower than their single knockout counterparts. Interestingly, the postnatal double knockouts displayed hyperinsulinaemia, as shown by inappropriate plasma insulin levels, given their degree of hypoglycaemia. The single knockout mice also showed hyperinsulinaemia and had 31% lower plasma glucose than the wild-types. While the double knockouts did not survive more than 24 h after birth, the single knockouts reached adulthood and their hypoglycaemia continued. Therefore, APP and APLP2 expression modulates plasma insulin and glucose concentrations. Plasma calcium, magnesium and phosphate were also significantly reduced in the double knockouts compared to the wild-types, and they showed distinctive growth restriction, suggesting the involvement of a metabolic impairment. These results link the expression of the APP and APLP2 genes with glucose homeostasis and growth and therefore identify a novel function for the APP family.     

APP/PS1双转基因AD小鼠早期内质网应激诱导的凋亡

目的观察APP/PS1双转基因AD小鼠神经细胞凋亡,及内质网分子伴侣葡萄糖调节蛋白（GRP78）和内质网促凋亡因子半胱氨酸蛋白酶-12（Caspase-12）表达的改变,探讨APP/PS1双转基因AD小鼠早期内质网应激诱导的凋亡。方法选取5、7月龄的APP/PS1双转基因小鼠和同月龄同背景的野生型小鼠（WT）,分为5月龄WT组、5月龄APP/PS1组、7月龄WT组和7月龄APP/PS1组,每组6只,应用原位细胞凋亡检测法（TUNEL）检测凋亡细胞,免疫组织化学方法检测其脑内GRP78和Caspase-12的表达水平。结果 TUNEL检测凋亡率分别为7月龄APP/PS1鼠（35.0±6.31）%、5月龄APP/PS1鼠（9.0±2.78）%、7月龄WT鼠（4.0±1.89）%、5月龄WT鼠（4.0±1.83）%,其中7月龄APP/PS1鼠凋亡率显著升高（P〈0.05）;免疫组织化学检测GRP78阳性率分别为7月龄APP/PS1鼠（30.0±5.43）%、5月龄APP/PS1鼠（10.0±2.12）%、7月龄WT鼠（2.0±1.71）%、5月龄WT鼠（3.0±1.41）%,7月龄APP/PS1鼠GRP78表达明显升高（P〈0.05）;免疫组织化学检测Caspase-12阳性率分别为7月龄APP/PS1鼠（33.0±5.98）%、5月龄APP/PS1鼠（12.0±2.60）%、7月龄WT鼠（4.0±2.56）%、5月龄WT鼠（2.0±1.79）%,7月龄APP/PS1鼠Caspase-12表达明显升高（P〈0.05）。结论 7月龄的APP/PS1双转基因小鼠出现了内质网应激诱导的凋亡。本实验结果为临床AD早期预防和治疗提供了重要依据。     

噻唑烷二酮通过Wnt通路改善2型糖尿病大鼠海马阿尔茨海默病样病变

目的:2型糖尿病(T2DM)是阿尔茨海默病(AD)发病的重要风险因子。本研究运用噻唑烷二酮类药物(TZD)对T2DM大鼠进行干预,检测W nt途径在用药前后变化,探讨TZD降低T2DM大鼠AD发生风险的可能机制。方法:造T2DM大鼠模型,TZD分别灌胃2周(TZD2W)及4周(TZD4W)。葡萄糖氧化酶法检测血浆葡萄糖水平,放免法检测血浆胰岛素水平,免疫印迹技术检测大鼠海马tau蛋白、tau蛋白上部分磷酸化位点及β淀粉样蛋白(Aβ)前体APP水平,W nt途径中β-联蛋白(β-caten in)和糖原合成激酶3β(GSK-3β)水平,及TZD作用物PPARγ水平。免疫组化技术检测各组大鼠海马Aβ沉积程度。结果:T2DM组及TZD2W组血糖、胰岛素水平及胰岛素抵抗程度显著高于对照组,TZD4W组虽胰岛素水平仍显著高于对照组,但血糖及胰岛素抵抗程度已明显下降,与对照组比较无显著差别。T2DM组大鼠海马tau蛋白上位点Ser199/202、Ser422磷酸化程度及Aβ前体APP水平均显著高于对照组,经TZD干预后,tau蛋白上上述位点磷酸化程度逐渐下降,Aβ沉积逐渐减少;T2DM组大鼠大脑PPAR-γ水平与对照组比较无差异,但运用TZD后,PPAR-γ水平显著升高;T2DM组大鼠大脑W nt途径中β-caten in水平下降,GSK-3β活性升高,运用TZD干预2周和4周大鼠大脑β-caten in水平显著升高,GSK-3β活性显著下降。结论:TZD干预可降低T2DM时AD发病风险。TZD通过上调W nt通路改善2型糖尿病大鼠海马AD样病变。该作用先于胰岛素信号转导通路。