雌激素对血管性痴呆大鼠认知功能及海马CA1区胰岛素样生长因子-1、胆碱乙酰转移酶表达的影响

目的 探讨雌激素对血管性痴呆(VD)大鼠认知功能及海马CA1区胰岛素样生长因子-1(IGF-1)、胆碱乙酰转移酶(ChAT)表达的影响.方法 30只雄性SD大鼠随机分为假手术组、VD组和雌激素组,每组10只.采用双侧颈总动脉结扎(2VO)法制备VD大鼠模型;雌激素组大鼠腹腔注射17-β雌二醇(花生油溶解)1 mg/kg,假手术组和VD组大鼠腹腔注射等量的花生油,均为隔日1次,共30次.60 d后,用Morris水迷宫检测各组大鼠逃避潜伏期和跨越平台次数;HE染色观察大脑海马CA1区神经细胞形态学变化,免疫组化染色检测海马CA1区IGF-1、ChAT阳性细胞数.结果 假手术组海马CA1区未见明显的病理变化;VD组神经细胞数量和层次明显减少;雌激素组偶见小的软化灶,细胞数和形态接近假手术组.与假手术组相比,VD组及雌激素组逃避潜伏期明显延长,跨越平台次数明显减少,海马CA1区IGF-1表达明显增加,ChAT表达明显减少(均P<0.05);与VD组比较,雌激素组逃避潜伏期明显缩短,跨越平台次数明显增加,海马CA1区IGF-1及ChAT表达明显增加(均P<0.05).结论 雌激素可以通过上调内源性IGF-1而减轻海马神经元损伤,增加ChAT的表达,改善VD大鼠认知功能.     

雌激素对血管性痴呆大鼠认知功能、海马Bcl-2、Bax蛋白表达及神经元凋亡的影响

目的 探讨雌激素对血管性痴呆(VD)大鼠认知功能、海马Bcl-2、Bax蛋白表达和神经元凋亡的影响.方法 60只雄性大鼠随机分为假手术组、VD组和雌激素组,每组20只.采用双侧颈总动脉结扎法制备VD大鼠模型;雌激素组腹腔注射17-β雌二醇(花生油溶解)200 μg/kg,同时假手术组和VD组腹腔注射等量的花生油,均为隔日1次,共30次.60 d后,Y-型迷宫试验检测大鼠学习记忆能力;HE染色观察大鼠海马神经元形态;免疫组化染色检测海马Bcl-2、Bax蛋白的表达,原位缺口末断标记(TUNEL)法检测神经元凋亡程度.结果 与假手术组相比,VD组及雌激素组认知能力明显下降, 海马CA1区Bcl-2、Bax蛋白表达增加,TUNEL 阳性细胞数明显增多(均P<0.001);与VD组比较,雌激素组认知能力改善,海马CA1区Bcl-2蛋白表达明显增加,Bax蛋白的表达明显减少,TUNEL 阳性细胞明显减少 (均P<0.001).结论 17-β雌二醇可调节Bcl-2、Bax蛋白表达而抑制神经元凋亡,有助于改善VD大鼠的认知能力.     

雌二醇对血管性痴呆大鼠海马CA1区GFAP表达的影响

目的研究17β-雌二醇对血管性痴呆(vascular dementia,VD)大鼠海马CA1区GFAP表达的影响,探讨雌激素对血管性痴呆大鼠中枢神经系统保护作用的机制。方法采用结扎双侧颈总动脉方法制备血管性痴呆动物模型,腹腔注射不同剂量17β-雌二醇60d后,应用Y迷宫检测各组VD大鼠认知功能以及免疫组化法等检测大鼠大脑海马CA1区GFAP表达的变化。结果腹腔注射17β-雌二醇60d后,大鼠认知功能显著改善;学习、记忆功能测试30次的正确次数较实验对照组明显增高(P<0.05),造模60d后的大鼠,其脑内CA1区GFAP免疫阳性细胞数较假手术组显著增高,而雌二醇组大鼠CA1区GFAP免疫阳性细胞数较实验对照组显著减少。结论雌激素补充疗法能选择性影响血管性痴呆大鼠脑内CA1区GFAP阳性细胞,并有可能影响学习和记忆能力。     

雌二醇对血管性痴呆大鼠海马CA1区GFAP表达的影响

目的研究17β-雌二醇对血管性痴呆（vascular dementia，VD）大鼠海马CA1区GFAP表达的影响，探讨雌激素对血管性痴呆大鼠中枢神经系统保护作用的机制。方法采用结扎双侧颈总动脉方法制备血管性痴呆动物模型，腹腔注射不同剂量17β-雌二醇60d后，应用γ迷宫检测各组VD大鼠认知功能以及免疫组化法等检测大鼠大脑海马CA1区GFAP表达的变化。结果腹腔注射17β-雌二醇60d后，大鼠认知功能显著改善；学习、记忆功能测试30次的正确次数较实验对照组明显增高（P〈0．05），造模60d后的大鼠，其脑内CA1区GFAP免疫阳性细胞数较假手术组显著增高，而雌二醇组大鼠CA1区GFAP免疫阳性细胞数较实验对照组显著减少。结论雌激素补充疗法能选择性影响血管性痴呆大鼠脑内CA1区GFAP阳性细胞，并有可能影响学习和记忆能力。     

γ-氨基丁酸对慢性脑缺血致血管性痴呆大鼠学习记忆能力的影响

目的观察γ-氨基丁酸（GABA）对慢性脑缺血致血管性痴呆（VD）大鼠学习记忆能力及海马CA1区神经元形态学的影响。方法将SD大鼠随机分为假手术组、模型组、GABA组,采用双侧颈总动脉永久性结扎法建立VD模型。GABA组术后腹腔注射GABA0.5g.kg-1.d-1,连续注射60d;用Morris水迷宫实验检测大鼠空间学习记忆能力;Nissl染色观察大鼠海马CA1区神经元形态学变化。结果 GABA能明显改善VD大鼠学习记忆能力,也能减轻海马CA1区神经元损伤。结论 GABA能改善慢性脑缺血致VD大鼠的学习记忆能力,减轻海马神经元损伤可能是其机制之一。     

血管性痴呆大鼠海马区核因子-κB、环氧合酶-2的表达变化

目的通过检测血管性痴呆(vascular dementia,VD)大鼠海马CA1区核因子-κBp65(nuclear factor-κB p65,NF-κBp65)与环氧合酶-2(cyclooxygenase-2,COX-2)的表达,探讨NF-κB、COX-2对VD大鼠的损伤作用。方法28只大鼠随机分为两组,假手术(SOG)组(n=13)和模型(VD)组(n=15),采用HE染色,光镜下观察海马CA1区锥体细胞的改变,免疫组化方法检测海马CA1区NF-κBp65、COX-2蛋白的表达。结果与假手术组相比,模型组组海马CA1区锥体细胞损伤、丧失明显,NF-κBp65、COX-2蛋白表达高于假手术组,与假手术组相比有统计学意义(P(0.01)。结论血管性痴呆大鼠海马CA1区NF-κBp65、COX-2蛋白的表达增加,NF-κBp65、COX-2蛋白的高表达可能是学习记忆障碍的原因之一。     

17β-雌二醇对血管性痴呆大鼠海马CA1区神经突触可塑性的影响

目的探讨突触可塑性在17p雌二醇改善血管性痴呆（VD）大鼠认知功能障碍中所起的作用。方法选用〉16月龄雄性Wistar大鼠,应用Y迷宫进行空间定向学习和记忆训练,将达到标准者随机分为3组：（1）假手术（Sham）组;（2）VD组;（3）VD＋雌二醇腹部皮下注射（E）组。应用免疫组织化学染色及RT—PCR的方法,检测大鼠海马CA1区微管相关蛋白2（MAP-2）和突触素（SYN）蛋白含量和mRNA表达水平的改变。结果术后60d,E组和VD组MAP-2和SYN表达均有下降,但VD组下降更为明显。结论17β-雌二醇相对增加VD大鼠海马CA1区MAP-2、SYN蛋白含量和mRNA的表达。提示相对增加与突触可塑性相关的MAP-2、SYN蛋白含量和mRNA的表达,可能是雌二醇改善VD认知功能障碍的机制之一。     

血管性痴呆大鼠海马区核因子-κB、环氧合酶-2的表达变化

目的 通过检测血管性痴呆(vascular dementia,VD)大鼠海马CA1区核因子-κBp65(nuclear factor-κB p65, NF-κBp65)与环氧合酶-2(cyclooxygenase-2,COX、2)的表达,探讨NF -κB和COX-2的损伤作用.方法 28只大鼠随机分为假手术组(SOG)13只和模型组(VD)15只,取海马CA1区为观察部位,HE染色观察锥体细胞的改变,免疫组化检测NF-κBp65、COX-2的表达.结果 与SOG相比,VD大鼠海马CA1区锥体细胞损伤、丧失明显,NF-κBp65、COX-2蛋白增加,差异有统计学意义(P﹤0.01).结论 VD大鼠海马CA1区NF-κBp65、COX-2蛋白的高表达可能是学习记忆障碍的原因之一.     

冈田酸对拟AD模型大鼠海马CA1区Aβ1-40和nNOS表达的影响

目的观察冈田酸(OA)对大鼠海马CA1区Aβ1-40和nNOS表达的影响,建立更接近临床表现的拟AD大鼠模型。方法在大鼠海马CA1区多次微量注射OA,水迷宫实验观测大鼠行为学改变;Bielschowsky染色观察海马CA1区神经原纤维缠结(NFT)和老年斑(SP)等特征性病理变化;免疫组化方法观察海马CA1区Aβ1-40和nNOS的表达。结果模型组学习记忆减退;海马CA1区出现NFT(P<0.05)和SP特征性病理变化,及Aβ1-40的高表达(P<0.05)和nNOS的低表达(P<0.05)。结论冈田酸海马CA1区微量多次注射,可建立更接近AD临床表现和病理特征的大鼠模型,大鼠海马CA1区SP和NFT的形成,以及Aβ1-40表达增加、nNOS表达减少,是该模型大鼠学习记忆能力减退的可能机制。     

脑室注射痴呆大鼠海马胶质纤维酸性蛋白表达与学习记忆能力的关系

目的探讨星形胶质细胞在老年性痴呆大鼠海马中的表达与老年性痴呆大鼠学习记忆能力减退的关系。方法雄性SD大鼠20只,随机分为痴呆组与假手术组;用Morris水迷宫检测大鼠的学习、记忆能力;用免疫组化技术定量检测大鼠海马CA1区胶质纤维酸性蛋白(GFAP)的表达;分析海马星形胶质细胞变化与学习、记忆能力的关系。结果假手术组海马CA1区锥体细胞排列紧密有序,细胞核大而圆、染色浅、核仁明显、未见明显胞浆浓染、核固缩等神经元变性受损征象。而痴呆大鼠海马CA1锥体神经细胞排列疏松、数目减少、细胞形态异常,许多细胞出现体积缩小、核浓染、核固缩;痴呆鼠海马CA1区GFAP阳性细胞数目明显增多,胞体肥大,突起增粗、变长现象明显,而假手术组海马CA1区仅见少量GFAP阳性细胞,突起较少、短,染色较淡。计数和测量海马CA1区GFAP阳性细胞数目、总面积、平均光密度,痴呆组与假手术组相比均明显增加,有显著意义(P<0.05);水迷宫测试显示痴呆组大鼠隐藏平台获得时间比假手术组明显延长,空间探索时间明显缩短,具有显著意义(P<0.05);显示痴呆组大鼠学习记忆能力与假手术组比较均明显下降;将痴呆大鼠学习成绩与海马CA1区GFAP表达数目之间进行相关分析,两者间存在负相关关系,认为星形胶质细胞参与了学习记忆过程。结论提示海马星形胶质细胞的过度表达可能影响痴呆大鼠的学习记忆能力。     

Immunolocalization of VR1 and VRL1 in rat larynx

Immunoreactivity for vanilloid receptor subtype 1 (VR1) and its analogue vanilloid receptor-like protein 1 (VRL1) were examined in combination with immunoreactivity for substance P (SP) and calcitonin gene-related peptide (CGRP) in the rat larynx. VR1 and VRL1 immunoreactivity were observed in the intraepithelial free nerve endings, subepithelial nerve plexus and laryngeal epithelial cells. Most of VR1 immunoreactive nerves were also immunoreactive for SP or CGRP. VR1 immunoreactive intraepithelial nerve endings may be laryngeal nociceptors.     

Pin1和Bmi1在人类胶质瘤中的表达及其意义

目的 研究人类肽基脯氨酰异构酶(Pin1)和B细胞特异单克隆鼠白血病毒整合位点基因(Bmi1)在人类胶质瘤中的表达,并探讨它们与胶质瘤分化程度的关系.方法 制作由WHO Ⅱ级胶质瘤组织30例、WHO Ⅲ级胶质瘤组织19例、WHO Ⅳ级胶质瘤组织21例与正常脑组织13例组成的组织芯片,免疫组化方法检测Pin1和Bmi1的表达情况.结果 Pin1和Bmi1在WHO Ⅱ、Ⅲ、Ⅳ级胶质瘤阳性率分别是(35±3.7)%,(63.7±3.9)%,(77.9±9.2)%和(20.1±5.1)%,(55.1±6.3)%,(61.7±2.7)%,均高于各自正常组(10.7±2.9)%和(7.9±1.3)%,均为P＜0.05.Pin1和Bmi1表达与胶质瘤等级呈正相关.结论 Pin1和Bmi1可能在胶质瘤发生过程中起重要作用.Pin1和Bmi1的表达检测可能成为胶质瘤的有效诊断指标.     

糖尿病大鼠海马endophilin-A1和dynamin-1的表达研究

目的研究糖尿病大鼠海马组织endophilin-A1和dynamin-1的表达,以期进一步研究其与糖尿病认知功能损害的关系。方法 14只雄性SD大鼠随机分为两组:正常对照(NC)组和糖尿病(DM)组。腹腔注射链脲佐菌素55mg.kg-1制备糖尿病模型,5周后断头取材,分别进行如下实验:①Western Blot法检测海马组织endophilin-A1和dynamin-1的表达;②免疫组化法观察海马区dynamin-1的表达。用SPSS17.0软件作独立样本t检验。结果①Endophilin-A1和dynamin-1在两组大鼠海马组织中均有表达,其中DM组(0.66±0.12,p=0.004)endophilin-A1的aD值明显低于NC组(0.97±0.07),Dynamin-1在两组中的aD值差别无统计学意义(p=0.841);②免疫组化法显示海马CA3区、DG区dynamin1在各组中均有表达,差异无统计学意义(p=0.114,p=0.783)。结论糖尿病大鼠海马组织endophilin-A1表达下调,而dynamin-1表达未发现明显改变,值得进一步研究以探讨二者与糖尿病突触功能损害的关系。     

The role of DTNBP1, NRG1, and AKT1 in the genetics of schizophrenia in Finland

Several putative schizophrenia susceptibility genes have recently been identified. Significant associations between schizophrenia and neuregulin 1 (NRG1) and dysbindin (DTNBP1) were first reported in 2002 and studies in several populations have since independently reported positive associations to these gene regions. Further, both tentative functional and genetic data have implicated the role of AKT1 in the genetic background of this disorder. However, findings have not been consistent in all populations. We investigated the allelic diversity of these three genes NRG1, DTNBP1 and AKT1 in a representative nation-wide study sample of 441 Finnish schizophrenia families consisting of 865 affected individuals, in order to assess their role in one of the largest population-based study samples. DTNBP1 and AKT1 failed to show evidence of association, whereas two SNPs in the 3' region of the NRG1 gene yielded suggestive evidence of association (p=0.012 and p=0.048) in family-based association analyses. Thus, our study does not indicate that AKT1 or DTNBP1 play a role in the etiology of schizophrenia in the Finnish population. Furthermore, results do not support a major role for NRG1, but we cannot completely exclude a minor role of this gene in the Finnish population.     

Expression of inducible nitric oxide synthase, interleukin-1 and caspase-1 in HIV-1 encephalitis

Inflammatory cytokines and enzymes such as IL-1 and inducible nitric oxide synthase (iNOS) may play an important role in the pathogenesis of AIDS dementia, a condition associated with infection of the CNS cells by the HIV-1. In this report, we investigated the expression of iNOS, IL-1, and caspase-1 (interleukin-1 converting enzyme) in HIV-1 encephalitis (HIVE) by immunocytochemistry and analyzed their expression with respect to HIV-1 infection and glial activation. In HIVE, all three molecules were expressed at high levels in areas of HIV-1 infection (microglial nodules with HIV-1 p24 immunoreactivity) and in areas of diffuse white matter gliosis. Expression was cell-type specific, with IL-1 and caspase-1 being expressed in macrophages and microglia, and iNOS in activated astrocytes. Multinucleated giant cells, a hallmark of virally infected cells, showed intense staining for both IL-1 and caspase-1, suggesting induction of these molecules by HIV-1. Double immunocytochemistry demonstrated a regional co-localization of astrocyte iNOS and microglial IL-1 and caspase-1. These results support the notion that autocrine and paracrine interactions between HIV-1 infected macrophages and microglia, activated microglia, and astrocytes lead to expression of proinflammatory and neurotoxic molecules. iNOS and caspase-1 may provide additional therapeutic targets for HIVE.     

Involvement of IGF-1 and IGFBP-1 and -3 in Axon-Schwann Cell Interactions

Insulin-like growth factor-I (IGF-I) promotes proliferation, differentiation and survival of Schwann cells (SC). Moreover, an effect of IGF-I on axon regeneration has been proposed. However, although IGF-I expression has been shown in postnatal SC and in SC precursors thus suggesting an autocrine regulation of SC survival, release of the trophic factor by SC has not been clearly demonstrated. To investigate the role of the IGF system, we studied the supernatant of primary SC cultures, purified sensory neuron cultures, and co-cultures of SC and sensory neurons. Moreover, since in its free form IGF-I interacts with specific binding proteins (IGFBPs) whose active role in modulating the effects of IGF-I is increasingly recognized, in the same culture systems we also evaluated levels of IGFBP-1 and -3. We established SC, sensory neuron and SC/sensory neuron cultures according to classical procedures. Purified SC (87,500 cells/dish) were grown in presence of serum, forskolin, cholera toxin and bovine pituitary extract. Purified sensory neurons were grown in the presence of serum and NGF; part of it was maintained alone and the rest was added with SC (87,500 cells/dish) and grown in a co-culture system. After 1 month all cultures were washed with PBS and grown for at least 4 days in a serum-free medium before collecting their conditioned media (CM) for chromatography assays. Similar IGF-I levels were found into the CM of SC and of sensory neurons when grown as purified cultures (94.40 vs 73.80 ng/5×10⁶ cell). Instead, higher amounts of IGF-I were detected into the medium of SC/sensory neurons co-cultures (277.70 ng/5×10⁶ cell). IGFBP-1 and -3 production was also found in both SC and sensory neuron purified cultures, but their expression was clearly higher in neurons compared to SC (0.74 vs 0.28 ng/5×10⁶ cell for IGFBP-1 and 4.48 vs 1.77 ng/5×10⁶ cell for IGFBP-3). Furthermore, SC/sensory neuron co-cultures maintained high levels of IGFBP-3 (3.93 ng/5×10⁶) but not of IGFBP-1 (0.28 ng/5×10⁶). In conclusion, IGF-1 is produced by both SC and pure sensory neurons, but co-culturing the two cell populations results in a possible reciprocal stimulation to synthesize this growth factor. Moreover, the decrease of IGFBP-1 in the medium of co-cultures could be due to the production of IGFBP proteases by SC. This action could be a mechanism to increase IGF-1 availability to the specific receptor.     

A Comparison of Cochlear Microphonics and N1 in Audiogenic-Seizure-Susceptible and Control Rats1

Abstract

Although numerous studies have shown that cochlear impainnent exists in audiogenic-seizure (AGS)-susceptible mice, there is only one report of cochlear potentials obtained from AGS-susceptible rats. To investigate the hypothesis that cochlear impairment also exists in AGS rats, cochlear microphonics (CM) and the primary afferent activity of the auditory division of the eighth cranial nerve (N₁) were studied in AGS rats.

AGS rats were obtained from the Veterans Administration Medical Center (Shreveport, La.) colony of Sprague Dawley derived animals, and control rats were obtained from Sprague Dawley, Inc. Two school bells ringing simultaneously were used to produce a sound of approximately 115 dB (AGS test stimulus). Exposure to the AGS test stimulus was once per week for three consecutive weeks. Chloramphenicol was used to treat the frequent otitis media found in the colony of AGS rats.

Two categories of AGS-susceptible and control rats were studied: (1) rats exposed to the AGS test stimulus and chloramphenicol regimen; and (2) rats not receiving these treatments. All rats were anesthetized with i.p. Dial-Urethane and prepared for cochlear round window recording. Cochlear microphonics were recorded in response to pure tones of 4, 8, 12, and 15 KHz, and N₁ was recorded in response to a click stimulus. A significant decrease in cochlear sensitivity was seen in both groups of AGS rats when compared to appropriate controls as reflected by a 25-35 dB shift in all CM and N₁ input-output functions. These results support the hypothesis that a functional cochlear impairment exists in the AGS rat.     

Molecular comparison of GLT1+ and ALDH1L1+ astrocytes in vivo in astroglial reporter mice

Astrocyte heterogeneity remains largely unknown in the CNS due to lack of specific astroglial markers. In this study, molecular identity of in vivo astrocytes was characterized in BAC ALDH1L1 and BAC GLT1 eGFP promoter reporter transgenic mice. ALDH1L1 promoter is selectively activated in adult cortical and spinal cord astrocytes, indicated by the overlap of eGFP expression with ALDH1L1 and GFAP, but not with NeuN, APC, Olig2, IbaI, PDGFRα immunoreactivity in BAC ALDH1L1 eGFP reporter mice. Interestingly, ALDH1L1 expression levels (protein, mRNA, and promoter activity) in spinal cord were selectively decreased during postnatal maturation. In contrast, its expression was up-regulated in reactive astrocytes in both acute neural injury and chronic neurodegenerative (G93A mutant SOD1) conditions, similar to GFAP, but opposite of GLT1. ALDH1L1(+) and GLT1(+) cells isolated through fluorescence activated cell sorting (FACS) from BAC ALDH1L1 and BAC GLT1 eGFP mice share a highly similar gene expression profile, suggesting ALDH1L1 and GLT1 are co-expressed in the same population of astrocytes. This observation was further supported by overlap of the eGFP driven by the ALDH1L1 genomic promoter and the tdTomato driven by a 8.3kb EAAT2 promoter fragment in astrocytes of BAC ALDH1L1 eGFP X EAAT2-tdTomato mice. These studies support ALDH1L1 as a general CNS astroglial marker and investigated astrocyte heterogeneity in the CNS by comparing the molecular identity of the ALDH1L1(+) and GLT1(+) astrocytes from astroglial reporter mice. These astroglial reporter mice provide useful in vivo tools for the molecular analysis of astrocytes in physiological and pathological conditions.