常压高氧对淀粉样蛋白前体/早老素1双重转基因小鼠脑内老年斑及β-淀粉样蛋白的影响

目的 探讨常压高氧(40%O_2,60%空气)处理淀粉样蛋白前体/早老素1(APP/PS1)双重转基因小鼠是否发挥神经保护作用.方法 对APP/PS1双重转基因阿尔茨海默病(AD)模型种鼠交配后产下的子代小鼠进行基因分型,待子代达10周龄时,取双重转基因小鼠40只,随机分成A、B、C、D 4组,每组10只,A、B 2组小鼠喂养于常压高氧中8 h/d,A组持续4周,B组持续8周;C、D组喂养于空气中4或8周,分别作为A、B组的对照.高氧处理后采用免疫组织化学、Thioflavin S染色检测小鼠脑组织形态学的变化,Western blot检测APP代谢过程中相关蛋白的表达变化,ELISA定量检测小鼠脑内β-淀粉样蛋白(Aβ)水平的变化.结果 免疫组织化学和Thioflavin S染色均显示,与对照组相比,高氧处理组小鼠皮质和海马内老年斑数量明显减少,B组比A组减少更显著.高氧处理组小鼠脑内C_(99)、C_(83)水平显著高于对照组,Aβ水平明显低于对照组,但各组小鼠脑内全长APP及β位淀粉样前体蛋白裂解酶1(BACE1)蛋白水平无明显改变.ELISA结果提示,B组小鼠海马和皮质内Aβ_(40)[(783.6±97.2)pg/ml]和Aβ_(42)[(175.3±17.1)ps/ml]含量明显低于对照组Aβ_(40)[(1251.6±42.3)pg/ml,t=9.36,P<0.01]和Aβ_(42)[(286.8±13.0)pg/ml,t=13.7,P<0.01]的含量.结论 常压高氧处理能显著减少AD模型小鼠脑内Aβ的产生、沉积及老年斑的形成;这种改变可能通过减少Aβ产生或加速Aβ清除实现.     

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。     

脐血间充质干细胞外泌体对APP/PS1小鼠海马神经元的保护作用及其机制

目的 研究脐血间充质干细胞外泌体(MSC-EXO)对阿尔茨海默病(AD)小鼠海马神经元的保护作用及其机制。方法 将20只APP/PS1小鼠随机分为AD+saline组和AD+EXO组,每组10只;将10只野生型C57小鼠作为正常对照组。AD+EXO组小鼠经尾静脉注射EXO悬液,AD+saline组和对照组小鼠注射等体积的生理盐水。30 d后取脑,用免疫组织化学染色检测脑内Aβ负荷,尼氏染色检测神经元的数量及尼氏小体,透射电子显微镜观察海马神经元的超微结构,Western blot检测海马Nrf2、Keap1及HO-1的表达量。结果 与对照组相比,AD+saline小鼠脑内有大量Aβ沉积,Aβ阳性面积明显增多,海马DG区神经元数量减少(P 0. 01);并且海马神经元的线粒体出现明显肿胀、空泡化等损伤表现。与AD+saline相比,AD+EXO小鼠皮层与海马组织的Aβ负荷降低,海马DG区的神经元数量显著增多(P 0. 05),线粒体水肿、空泡化减轻。与对照组相比,AD+saline组小鼠海马Nrf2、HO-1蛋白的表达量升高,Keap1蛋白的表达量降低(均P 0. 05);而AD+EXO组与AD+saline组相比,Nrf2和HO-1蛋白的表达量降低,Keap1蛋白的表达量升高(均P 0. 05)。结论MSC-EXO可能通过调节Nrf2/Keap1通路,而发挥对APP/PS1小鼠海马神经元的保护作用。     

基质细胞衍生因子-1对阿尔茨海默病脑内可溶性Aβ清除作用的研究

目的通过对APP/PS1双转基因小鼠侧脑室持续注射基质细胞衍生因子-1(SDF-1),以观察SDF-1对脑内可溶性β淀粉样蛋白(Aβ)的影响及其可能的机制。方法将28周龄的野生型(wild type,WT)小鼠和APP/PS1转基因小鼠分为对照组和SDF-1α干预组,分别予以侧脑室注射SDF-1α和PBS,1周1次,连续注射4周和8周。采用ELISA法检测小鼠脑内可溶性Aβ的水平,采用Wsetern blot方法检测小鼠脑内小胶质细胞标志物Iba-1的水平。结果 SDF-1α侧脑室注射后APP/PS1小鼠脑内可溶性Aβ-40和Aβ-42水平与对照组相比明显减少,APP/PS1小鼠及WT小鼠脑内Iba-1水平较对照组增加。结论 SDF-1α侧脑室注射可能减少APP/PS1小鼠脑内可溶性Aβ的水平,其作用的机制可能是SDF-1α增加了脑内小胶质细胞由外周向中枢的募集,从而促进Aβ的吞噬清除。动员与趋化骨髓来源的小胶质细胞可能成为治疗AD的新靶点。     

姜黄素对AD小鼠海马神经元凋亡和GSK-3β表达及磷酸化的影响

目的观察姜黄素对AD小鼠模型海马神经元凋亡和糖原合成酶激酶3β表达及其磷酸化影响。方法将20只APP/PS1转基因小鼠随机分为AD模型组、AD模型+姜黄素组,每组10只,AD模型+姜黄素组腹腔注射剂量为400mg/(kg·d)姜黄素,1次/d,连续14d。取12只正常小鼠作对照组。采用扫描电镜检测小鼠海马神经元凋亡,Western blot检测GSK-3β、酪氨酸磷酸化GSK-3β(pTyr-GSK-3β)和丝氨酸磷酸化GSK-3β(pSer-GSK-3β)的表达情况。结果与对照组相比,模型组海马神经元出现染色质边集、线粒体肿胀、细胞器减少;pTyr-GSK-3β和pSer-GSK-3β的表达明显增加(t=5.112,P=0.005;t=5.619,P=0.006)。与模型组相比,姜黄素组海马神经元染色质呈弥散分布、线粒体嵴清晰可见、细胞器排列紧密,pTyr-GSK-3β表达明显降低(t=-7.985,P=0.001),pSer-GSK-3β表达明显提高(t=9.105,P=0.001)。结论 GSK-3β可能参与AD小鼠海马神经元损伤,姜黄素通过减少pTyr-GSK-3β、增加pSer-GSK-3β的表达抑制GSK-3β活性来减少AD小鼠海马神经元凋亡。     

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。     

铁和老年斑在阿尔茨海默病转基因小鼠脑内的沉积及其对磁共振T2弛豫时间的影响

目的 观察老年斑和铁在阿尔茨海默病(AD)转基因小鼠脑内皮质和海马处的沉积及其对磁共振活体扫描T2弛豫时间的影响.方法 2、4、6、8、10、12、14、16月龄的AD转基因小鼠各2只,分为幼龄组、成龄组和老龄组,8月龄野生型C57BL/6J小鼠2只作为对照,依次进行磁共振活体扫描,测量皮质、海马、丘脑、胼胝体、纹状体等结构的T2弛豫时间,扫描完成后,进行铁和老年斑的组织学染色,计算皮质和海马处老年斑的数目及含量、铁颗粒的数目及含量.结果 各组皮质及海马T2弛豫时间(ms)分别为:野生组:49.5±2.1、51.6±1.1;幼龄组(2、4月龄):49.7±0.5、50.7±0.7;成龄组(6、8、10月龄):47.2±0.8、47.7±0.9;老龄组(12、14、16月龄):44.6±0.8、45.3±0.4.各组皮质及海马T2弛豫时间差异有统计学意义(皮质F=18.620,海马F=67.925,均P＜0.01).组间比较示成龄组较幼龄组(皮质q=4.284,海马q=7.902;均P＜0.01)及野生组(皮质q=4.424,P＜0.05,海马q=11.450,P＜0.01)小鼠皮质及海马T2弛豫时间缩短;而老龄组较成龄组小鼠皮质及海马T2弛豫时间缩短(皮质q=4.812,海马q=7.034,均P＜0.01).组织学染色示4月龄转基因小鼠皮质和海马开始出现老年斑的沉积,6月龄开始出现铁的沉积,并且随着小鼠月龄的增加,皮质和海马处老年斑和铁的数目及含量均明显增加.老年斑和铁的沉积具有明显的正相关(r=0.931,P＜0.01),老年斑的含量、铁的含量与T2弛豫时间均具有明显的负相关(分别r=-0.884、-0.827,均P＜0.01).结论 老年斑和铁的沉积可能共同影响T2弛豫时间,提示T2弛豫时间可以作为早期诊断AD和抗痴呆药物筛选的一个敏感性指标.     

氯硝西泮改善APP/PS1痴呆模型小鼠大脑超兴奋性和认知障碍

目的探讨APP/PS1痴呆模型小鼠大脑中间神经元的数量变化和大脑超兴奋性以及认知功能3者之间的关系。方法利用7个月龄雄性小鼠WT小鼠和APP/PS1小鼠,通过免疫荧光染色,观察海马齿状回区神经肽Y(NPY)和皮质NPY、小清蛋白(PV)、钙网膜蛋白(CR)阳性中间神经元数量变化。将7个月龄雄性APP/PS1分为2组,注射生理盐水组和注射氯硝西泮(CLZ)组,CLZ按0.025mg·kg-1的剂量在每次实验前30min进行腹腔注射,通过新物体识别实验记录和分析小鼠探索新物体的时间和速度之后进行脑电图(EEG)监测,记录和分析每小时癫痫样高尖波的数量变化。结果 APP/PS1小鼠和野生型相比,海马NPY阳性中间神经元和皮质的NPY、PV、CR阳性中间神经元的数量都大量减少,注射CLZ组APP/PS1小鼠较APP/PS1小鼠海马和皮质癫痫样高尖波的数量都显著减少,注射CLZ的APP/PS1小鼠较APP/PS1小鼠探索新物体时间有增加趋势。结论 APP/PS1小鼠的中间神经元数量减少导致大脑超兴奋性和认知障碍,CLZ能改善APP/PS1小鼠大脑超兴奋性和认知障碍。     

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。     

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。     

Denervation study of synapses of organ of corti of old world monkeys

Fine structural characteristics of synapses in the spiral organ of Corti were examined, with reference to differences between inner and outer haircell systems, and to location of neurons of origin of efferent axons. Surgical interruption of crossed olivocochlear bundle, of vestibular nerve, of facial nerve, and excision of superior cervical ganglia were used to determine the pathways of efferent axons. Interruption of the vestibular nerve near the brainstem results in degeneration of all efferent terminals on outer hair cells. Mid-line lesions at, and caudal to, the facial colliculus result in degeneration of about half of these efferent terminals. Efferent synaptic bulbs to the inner hair-cell system are small, of the order of one micron, and form type 2 junctions with afferent dendrites. They tend to have more large dense-core vesicles (about 80 nm) than the large efferent terminals of the outer hair-cell system, and appear to be the terminals of axons in the habenula perforata, which exhibit varicosities laden with large dense core vesicles. The varicosities are unaffected by excision of the superior cervical ganglia. So far as our material can reveal, it appears that the varicosities in the habenula perforata do not survive vestibular root interruption, nor do the efferent processes in the internal spiral bundle or at the base of inner hair cells. Most interestingly, the afferent processes of the inner hair-cell system, as identified for example by their relation to pre-synaptic bodies in the inner hair cells, are subject to a trans-synaptic reaction after severance of the vestibular root. They undergo a dramatic cytological transformation, characterized by increase of volume, engorgement with microtubules, microfilaments, microvesicles of various sizes, and clusters of lysosomes. Thus, both the efferent and afferent terminals of the inner hair-cell system show marked cytological differences from the corresponding terminals of the outer hair cell system.     

Mechanism of action of tubocurarine on nicotinic cholinoreceptors of neurons of the sympathetic ganglia of rats

Tubocurarine (Tc) effect on membrane currents elicited by acetylcholine (ACh) was studied in isolated superior cervical ganglion neurons of rat using patch-clamp method in the whole-cell recording mode. The "use-dependent" block of ACh current by Tc was revealed in the experiments with ACh applications, indicating that Tc blocked the channels opened by ACh. Mean lifetime of Tc-open channel complex, tau, was found to be 9.8 +/- 0.5 s (n = 7) at -50 mV and 20-24 degrees C. tau exponentially increased with membrane hyperpolarization (e-fold change in tau corresponded to the membrane potential shift by 61 mV). Inhibition of the ACh-induced current by Tc (3-30 microM/1) was completely abolished by membrane depolarization to the level of 80-100 mV. Inhibition of ACh-induced current was augmented at increased ACh doses. It is concluded that the open channel block produced by Tc is likely to be the only mechanism for Tc action on nicotinic acetylcholine receptors in superior cervical ganglion neurons of rat.     

The effect of age of onset of PD on risk of dementia

Background Dementia occurs in the majority of patients with Parkinson’s disease (PD). Late onset of PD has been reported to be associated with a higher risk for dementia. However, age at onset (AAO) and age at baseline assessment are often correlated. The aim of this study was to explore whether AAO of PD symptoms is a risk factor for dementia independent of the general effect of age. Methods Two community-based studies of PD in New York (n = 281) and Rogaland county, Norway (n = 227) and two population-based groups of healthy elderly from New York (n = 180) and Odense, Denmark (n = 2414) were followed prospectively for 3–4 years and assessed for dementia according to DSM-IIIR. All PD and control cases underwent neurological examination and were followed with neurological and neuropsychological assessments. We used Cox proportional hazards regression based on three different time scales to explore the effect of AAO of PD on risk of dementia, adjusting for age at baseline and other demographic and clinical variables. Findings In both PD groups and in the pooled analyses, there was a significant effect of age at baseline assessment on the time to develop dementia, but there was no effect of AAO independent of age itself. Consistent with these results, there was no increased relative effect of age on the time to develop dementia in PD cases compared with controls. Interpretation This study shows that it is the general effect of age, rather than AAO that is associated with incident dementia in subjects with PD. Received in revised form: 22 December 2005     

Limits of deinstitutionalization--perspectives of relatives of psychiatric patients

After a hopeful beginning, the social process of the reintegration of those with severe mental illness has come to a standstill. I am led to wonder whether "the community" really wants to live together with people suffering from severe mental illness, and if so, how closely? As long as the medical treatment of mental illness provided by the general practitioners is fundamentally deficient, as they are not able to prescribe the necessary interventions--such as out-patient psychiatric nursing, and service providers in the out-patient sector are content with offering increasingly intensive forms of care for the less seriously ill at the cost of the Social Welfare System--the reintegration of those with serious mental illness remains an illusion--which is mainly to the benefit of providers of residential care in homes and hostels.     

Summary of legislation of 1935 of interest to the department of Mental Hygiene

Psychiatric Quarterly -