局灶性脑缺血模型大鼠转录因子Olig1的表达变化及其在髓鞘修复中的作用

目的探讨Olig1在局灶性脑缺血后不同时间点的表达变化及其参与髓鞘修复的可能机制。方法线栓法建立大脑中动脉闭塞(middle cerebral artery occlusion,MCAO)模型,使用免疫组化和Western blot的方法观察脑缺血后1d、3d、7d、14d和28d Olig1的表达变化。碱性髓鞘蛋白(myelin basic protein,MBP)是髓鞘的组成成分,用作髓鞘的标志物,检测脑缺血后上述各时间点MBP的表达变化。结果正常大鼠Olig1广泛分布于脑白质和灰质,如皮层、胼胝体和纹状体等区域,典型地沿着神经纤维成束状排列。正常大鼠Olig1主要位于少突胶质细胞的胞浆,脑缺血后Olig1由胞浆移至细胞核。Olig1的表达在脑缺血后1d下降,3d回到正常水平并维持此水平到脑缺血后28d。MBP蛋白表达在脑缺血后1d至28d逐渐下降。结论 Olig1在脑缺血的初期表达下降,抑制了神经的再生,针对Olig1的表达规律进行干预将为脑缺血后髓鞘的修复提供理论依据。     

盐酸戊乙奎醚对高氧所致幼鼠脑损伤时Shh/Gli1信号通路的影响

目的 探讨盐酸戊乙奎醚对高氧所致幼鼠脑损伤时Shh/Gli1信号通路的影响。方法健康清洁级14d龄Sprague-Dawley(SD)幼鼠共30只,按照随机数字表法分为3组:对照组(C组)、高氧组(HO组)和高氧+盐酸戊乙奎醚组(HP组),每组10只。从造模第一天起,HP组幼鼠给予盐酸戊乙奎醚剂量为0.3mg/kg,于每日同一时间点给药,共计7d。C组和HO组均于相同时间点给予等容量的生理盐水。实验结束后进行神经功能缺损评分(NDS)。留取幼鼠海马并测定湿/干质量比(W/D)。光镜下观察海马CA1区病理学改变。原位末端标记法(TUNEL)测定海马CA1区细胞凋亡情况并计算细胞凋亡指数(AI)。免疫荧光法观察海马CA1区Shh和Gli1表达部位,蛋白免疫印迹法分别检测海马Shh和Gli1蛋白表达水平。结果 与C组比较,HO组幼鼠NDS、海马W/D、AI均升高(P0.05),海马CA1区正常锥体细胞计数减少(P0.05)。HP组幼鼠NDS、海马W/D、AI均较HO组降低(P0.05),海马CA1区正常锥体细胞计数较HO组增多(P0.05)。HO组幼鼠海马形态学结构发生明显损伤,HP组幼鼠海马形态学结构损伤有不同程度的减轻。与C组比较,HO组幼鼠海马Shh和Gli1表达水平均升高(P0.05)。HP组幼鼠海马Shh和Gli1表达水平均较HO组升高(P0.05)。结论 盐酸戊乙奎醚对高氧所致脑损伤发生的幼鼠脑组织具有保护作用,其机制可能与激活Shh/Gli1信号通路有关。     

大鼠局灶性脑缺血后少突胶质前体细胞激活及髓鞘再生的实验研究

目的探讨脑缺血再灌注大鼠少突胶质前体细胞(oligodendrocyte progenitor cells,OPCs)及髓鞘的表达变化。方法线栓法建立大脑中动脉闭塞(middle cerebral artery occlusion,MCAO)模型,免疫组化方法检测脑缺血再灌注后不同时间点1d、1w和2w不同脑区(梗死中心区、梗死周边区和梗死对侧区)OPCs特异性细胞标志物NG2的阳性细胞数及和髓鞘标志物碱性髓鞘蛋白(myelin basic protein,MBP)的表达变化。结果脑缺血后梗死中心区NG2阳性细胞数和MBP的表达随着再灌注时间延长而逐渐减少;梗死周边区NG2阳性细胞数在1w～2w增加,MBP的表达在24h～1w内降低,2w恢复到正常水平;梗死对侧区NG2阳性细胞数和MBP的表达无明显变化。梗死周边区OPCs细胞呈"单极"或"双极"分裂状,并从梗死灶的外带迁移到内带,提示OPCs细胞激活、增生并发生迁移。结论脑缺血再灌注后梗死周边区NG2细胞增多,使得一度缺失的成熟少突胶质细胞及髓鞘得到补充,提示NG2细胞可能参与缺血损伤的修复过程。     

大鼠局灶性脑缺血再灌注损伤后MBP、MAG Lingo-1的表达及丁苯酞对其的影响

目的探讨大鼠局灶性脑缺血再灌注损伤后脑组织中髓鞘碱性蛋白(MBP)、髓鞘相关糖蛋白(MAG)和Nogo受体作用蛋白-1(Lingo-1)表达情况及丁苯酞(NBP)对其的影响。方法 72只大鼠随机分为对照组、模型组和药物组。通过阻塞大鼠左侧大脑中动脉造成脑缺血2 h后再灌注1 d、3 d、5 d、7 d,建立大鼠局灶性脑缺血再灌注损伤模型。药物组大鼠腹腔注射丁苯酞20 mg/(kg·d),2次/d;对照组注射生理盐水。用免疫组化法检测大鼠缺血侧脑皮质MBP、MAG和Lingo-1的表达并测定相应灰度值。结果模型组、药物组较对照组MBP表达减少,MAG及Lingo-1表达增多;药物组较模型组MBP表达增多,MAG表达减少,差异均有统计学意义(P 0. 05);药物组和模型组Lingo-1表达差异无统计学意义(P 0. 05)。结论脑缺血再灌注诱发脑皮质髓鞘损伤,丁苯酞对受损髓鞘有一定保护作用。     

环孢素A对大鼠急性脑缺血再灌注损伤后髓鞘保护作用机制研究

目的观察环孢素A(CsA)对脑缺血再灌注损伤后大鼠海马CA1区iNOS以及胼胝体区髓鞘碱性蛋白(MBP)表达的影响,探讨其对髓鞘保护作用的可能机制。方法将SD大鼠随机分为假手术组、模型组、环孢素A组。改良线栓法制备建立大脑中动脉闭塞(MCAO)模型,环孢素A组从手术后2h～2周,每天腹腔注射环孢素A(20mg/kg),模型组和假手术组每天腹腔注射等体积的生理盐水;分别于手术后1d、3d、7d、14d免疫组化观察大鼠海马一区iNOS以及胼胝体区MBP的表达情况,同时对大鼠胼胝体区髓鞘染色。结果模型组、环孢素组iNOS 1d达峰,3d时下降但仍高于正常,7d及14d时接近正常。胼胝体MBP阳性纤维1d即有减少,3d更为明显,7d有所恢复,14d仍低于正常,经检验环孢素A组好于模型组(P<0.05)。结论环孢素A可显著减少缺血再灌注损伤后脑组织中iNOS的表达,促进MBP的恢复,有一定的髓鞘保护作用。     

白藜芦醇苷对脑梗死大鼠中Shh和Nrf2信号通路的调节及机制研究

目的观察大脑皮质Shh信号通路的转录因子Gli1、Ptch1与SOD1的动态表达,并探讨白藜芦醇苷脑保护作用及其对Gli1、Ptch1、Nrf2及SOD1的调节作用。方法采用线栓法建立大鼠永久性大脑中动脉闭塞模型。实验(一):SD大鼠随机分为7组:正常对照组以及建立局灶性缺血模型成功后3 h、6h、12 h、24 h、48 h、72 h共7个观察组,采用免疫组织化学方法、Western blot及RT-PCR观察缺血周围区Gli1,Ptch1和SOD1表达的变化。实验(二):SD大鼠随机分为4组:假手术组、溶剂对照组、和给药组(白藜芦醇苷25mg,50mg·kg~(-1))。术后24h和72 h分别采用免疫组织化学方法、Western blot及RT-PCR观察缺血周围区Gli1,Ptch1,Nrf2和SOD1表达的变化。结果免疫组织化学、Western blot及RT-PCR显示脑缺血6 h后Glil、Ptch1以及SOD1的表达开始升高,并于24 h达高峰,72 h后开始降低。白藜芦醇苷50mg·kg~(-1)能改善大鼠缺血后神经功能评分、减少梗死体积,显著升高缺血后Gli1、Ptch1、Nrf2和SOD1表达量的升高。结论大剂量白藜芦醇苷对局灶性脑缺血具有神经保护的作用。其保护作用可能与上调Gli1、Ptch1、Nrf2及SOD1的表达有关。     

肉苁蓉多糖通过Shh通路缓解EAE小鼠的临床症状

目的探讨音猬因子(Sonic hedgehog,Shh)通路在实验性自身免疫性脑脊髓炎(experimental autoimmune encephalomyelitis,EAE)小鼠发病过程中的作用,及肉苁蓉多糖(cistanche deserticola polysaccharide,CDPS)能否通过该通路缓解EAE小鼠临床症状。方法给予C57BL/6小鼠皮下注射髓鞘少突细胞糖蛋白35-55多肽(myelin oligodendrocyte glycoprotein 35-55,MOG35-55)抗原制备EAE动物模型。将60只小鼠随机分为正常对照组、EAE模型组、CDPS治疗组以及CDPS+Smo受体阻断剂环王巴明(cyc)治疗组(以下简称CDPS+cyc治疗组)4组,每组各15只。观察各组小鼠免疫注射后0~26d的临床症状评分,采用勒克斯光蓝染色(Luxol Fast Blue,LFB)检测各组小鼠脊髓组织内髓鞘脱失情况,Western blot法检测脊髓组织内Shh、碎片蛋白-1(Patched-1,Ptc-1)蛋白表达,采用RT-PCR检测脊髓组织内平滑蛋白(Smoothened,Smo)mRNA、神经胶质瘤相关癌基因1(Glioma-associated oncogene-1,Gli1)mRNA表达。结果自CDPS治疗第9天开始,CDPS治疗组小鼠临床症状评分低于EAE模型组(P<0.05),而CDPS+cyc治疗组临床症状评分高于CDPS组(P <0.05)。CDPS治疗组小鼠脊髓LFB评分较EAE模型组降低(t=9.64,P<0.01),而CDPS+cyc治疗组其LFB评分与EAE模型组比较差异无统计学意义(P>0.05)。EAE模型组小鼠脊髓组织内Shh、Ptc-1蛋白以及Smo mRNA、Gli1mRNA表达水平较正常组升高(均P<0.01),经CDPS治疗后,上述因子表达进一步升高(均P<0.01),而经cyc干预后,上述因子表达较CDPS治疗组降低(均P<0.01)。结论 CDPS对EAE小鼠临床症状有改善作用,其作用途径可能与Shh信号通路有关。     

实验性脑缺血损伤大鼠Nrf2/ARE信号通路相关基因NQO1、GCLC和GCLM表达的变化

目的从抗氧化应激角度观察大鼠脑缺血损伤后Nrf2/ARE信号通路相关基因NQO1、GCLC和GCLM mRNA及其蛋白表达的影响。方法将80只SD大鼠随机分为两组:假手术组(SO)和模型组(MCAO),采用线栓法制备局灶性脑缺血大鼠(MCAO)模型。每组大鼠40只,每组根据取材时间点12 h、1 d、2 d、3 d可以分为每组4个亚组,每个亚组10只大鼠。采用化学荧光法测定脑组织ROS水平,ELISA法检测GSH活性;分别采用qRT-PCR和Western blot法观察NQO1、GCLC和GCLM mRNA及其蛋白在缺血半暗带表达变化。结果 (1)与SO组比较,MCAO组脑组织中GSH活力显著降低,ROS活性显著升高(P 0. 05或P 0. 01);(2)与SO组比较,MCAO组各时间点NQO1、GCLC和GCLM mRNA及其蛋白表达均于缺血再灌注后12 h开始明显上升,24 h达高峰,随再灌注时间延长其表达逐渐下降,但仍保持较高表达水平(P 0. 05或P 0. 01)。结论大鼠脑缺血再灌注损伤后激活了Nrf2信号通路下游因子NQO1、GCLC和GCLM,从而发挥抗氧化应激作用。     

刺五加皂甙对脑缺血大鼠皮质少突胶质细胞变化的影响

目的观察刺五加皂甙对全脑缺血大鼠皮质少突胶质谱系细胞的影响作用,探讨其对缺血性脑损伤的防护作用机制。方法 70只SD大鼠随机分为假手术组、脑缺血组、刺五加皂甙组。采用四血管结扎的全脑缺血模型,制模成功后随机分为脑缺血组、刺五加皂甙组。刺五加皂甙组大鼠按剂量3.0mg/kg腹腔注射;用免疫组织化学法检测皮质少突胶质细胞标记物[2型星形胶质祖细胞标记物B5(A2B5)、少突胶质细胞标记物4(O4)、2’,3’-环核苷酸磷酸水解酶(CNPase)]及髓鞘碱性蛋白(MBP)表达的变化。结果与假手术组比较,脑缺血大鼠皮质A2B5表达1d时即已增多、1w时显著增多、并持续至1个月;O4、MBP表达于脑缺血1d时显著减少、1w时回升、1个月时恢复至假手术组水平;CNPase阳性表达在脑缺血后1d即显著下降、1w时减少到最低点、1个月时恢复至假手术组水平。与脑缺血组比较,刺五加皂甙组大鼠皮质A2B5表达有不同程度减少,O4、CNPase、MBP表达有不同程度增加。结论刺五加皂甙对少突胶质谱系细胞缺血性反应有保护作用。     

缺血后海马高迁移率族蛋白与星形胶质纤维酸蛋白表达及相关性

目的研究大鼠局灶性脑缺血再灌注星形胶质纤维酸蛋白(GFAP)与高迁移率族蛋白(HMGB1)在海马CA1区表达变化,探讨二者之间的关系。方法采用大脑中动脉栓塞2h制备SD大鼠脑缺血模型,60只雄性SD大鼠随机分为假手术组、缺血再灌注组,按1d、3d、7d、14d、28d时间点再分5个亚组,各时间点处死取脑,用免疫组化和荧光双标结合共聚焦扫描的方法来检测高迁移率族蛋白和星形胶质纤维酸蛋白在脑内海马CA1区表达变化。结果不同时间点缺血再灌注组GFAP、HMGB1表达均高于同时期的假手术组(P<0.05)。缺血再灌注组星形胶质细胞1d、3d、7d逐渐激活增生,7d达到高峰,14d开始下降;HMGB1在1d、3d、7d、14d是表达增加,14d达高峰,28d下降(与前一时间点比较P<0.05)。缺血再灌注组GFAP和HMGB1表达具有相关性(P<0.05),存在HMGB1和GFAP共定位细胞。结论脑缺血再灌注后,海马CA1区HMGB1增加与星形胶质细胞激活成正相关,过度表达的HMGB1和增殖的星形胶质细胞可能与缺血再灌注后神经元的迟发性损伤有关。     

Neuroimaging in epilepsy in tropics

Epilepsy is a major public health problem in many tropical countries. Also, some of the tropical diseases are major contributors to the higher prevalence of epilepsy in these countries. The etiologic factors responsible for epilepsy in these countries are quite different from those in the developed world. This article discusses the etiologic factors and neuroimaging of epilepsy in light of the conditions in these tropical countries.     

癫痫与抑郁关系的研究进展

抑郁是癫痫患者中常见的精神障碍,严重地影响了患者的生活质量。传统的观点认为癫痫患者因为存在着诸多社会学问题易出现抑郁倾向,癫痫和抑郁是单向的联系,但大量的研究已经证明癫痫和抑郁之间存在双向的联系,一种异常状态的存在可能易转化为另一种异常状态的发展。癫痫和抑郁存在着共同的发病机制。本文主要就癫痫和抑郁的双向联系以及抗抑郁药物在癫痫患者中的应用进行阐述。     

Increase in cathepsin D activity in rat brain in aging

Cathepsin D-like activity in homogenates of five brain areas of 3-month-old and 24-month-old Fischer 344 rats was measured. With hemoglobin as substrate at pH 3.2, more than 90% of the activity was inhibited by pepstatin. In each area studied, activity was more than twice as high in the old rat brain: 140-160% higher in the cortex, cerebellum, pons-medulla, and striatum and 90-100% higher in the hippocampus and spinal cord. The greatly increased metabolic capacity in the absence of an increase in protein turnover may have a role in age-related pathological degeneration in the brain.     

Sudanophilic lipid accumulation in astrocytes in periventricular leukomalacia in monkeys

Summary Sudanophilic lipid accumulation is a characteristic feature of periventricular leukomalacia (PVL) of infants. At least two types of lipid-containing cells have been identified, one being the macrophage, the other the pre-myelin glial cell. A third type of lipid-containing cell has been seen in two monkeys with spontaneous PVL. Electron microscopically this cell appears to be an astrocyte. This probably represents a reaction of the astrocyte to hypoxia and may be the equivalent of the hypertrophic astrocytes found in human infants.Supported in part by NIH grant HDO 8633 and the Regional Primate Research Center Grant RR-00166     

Issues in evaluation of cognition in the elderly in developing countries

Background:

Developing regions of the world host the majority of elderly subjects who are at risk for dementia. Reliable epidemiological data from these countries is invaluable in tackling this global problem. Scarcity of such data in literature is largely attributable to problems that are unique to developing communities worldwide.

Objective:

To classify and describe the problems that interfere with the collection of reliable epidemiological data on cognitive impairment in the elderly in developing communities, and to suggest practical solutions for some of them.

Methods:

Inferring from the experiences of a large, ongoing, population-based study on the cognitive impairments in the elderly in South India and from the review of literature.

Conclusion:

A fatalistic attitude regarding aging in the communities, significant heterogeneity in educational abilities and activities of daily living, high illiteracy among rural subjects, and lack of an organized health care system and updated demographic figures are some of the major factors that contribute to technical, namely, methodology-related problems and practical, namely, subject-related problems in such epidemiological studies.     

Characteristics of nociceptors in the periodontium--an in vitro study in rats

Recent studies have indicated that nociceptors can be classified into various types according to their physiological properties. These studies have clarified that the frequency distribution of various nociceptor types is different among body sites and animal species. In the present study, we investigated the physiological properties of rat's periodontal nociceptors in an in vitro jaw-nerve preparation. Responses were recorded from functional single filaments in the inferior alveolar nerve. To determine the nociceptor type, calibrated von Frey filaments, heat, and bradykinin (BK) stimuli were used. We found five subtypes of nociceptors in the periodontal ligaments of the lower incisor: Adelta-high threshold mechanonociceptors (Adelta-HTM, n=28), Adelta-mechanoheat nociceptors (Adelta-MH, n=6), Adelta-polymodal nociceptors (Adelta-POLY, n=26), C-high threshold mechanonociceptors (C-HTM, n=3) and C-polymodal nociceptors (C-POLY, n=4). Most nociceptors were Adelta-innervated, while only a small number of C-innervated nociceptors were found. The present results suggest that periodontal nociceptors transmit mainly fast pain, and may thus play a role in rapid detection of injure-related stimuli during mastication.     

Defects in Bioenergetic Coupling in Schizophrenia

Synaptic neurotransmission relies on maintenance of the synapse and meeting the energy demands of neurons. Defects in excitatory and inhibitory synapses have been implicated in schizophrenia, likely contributing to positive and negative symptoms as well as impaired cognition. Recently, accumulating evidence has suggested that bioenergetic systems, important in both synaptic function and cognition, are abnormal in psychiatric illnesses such as schizophrenia. Animal models of synaptic dysfunction demonstrated endophenotypes of schizophrenia as well as bioenergetic abnormalities. We report findings on the bioenergetic interplay of astrocytes and neurons and discuss how dysregulation of these pathways may contribute to the pathogenesis of schizophrenia, highlighting metabolic systems as important therapeutic targets.     

Progress in neuroprotection in Parkinson's disease

Slowing or aborting the progress of neurodegeneration in Parkinson's disease (PD) remains the most important unmet need of this disorder. There are several recent developments in trial design and also in drugs under investigation for possible neuroprotective effect. Emphasis has been placed on clinical as opposed to imaging end-points and these include change in a clinical rating scale, e.g. United Parkinson's disease Rating Scale (UPDRS), or time to additional therapy. The introduction of the delayed-start, or wash-in, trial design adds an additional dimension to drug evaluation for neuroprotection. Compounds that have been recently tested in clinical trial include the monoamine oxidase-B inhibitor rasagiline, the anti-apoptotic agents TCH346 and CEP1347, and the promitochondrial agent creatine. The dopamine agonists have been evaluated for a neuroprotective effect using imaging end-points. Perhaps the most important and simplest concept for neuroprotection has been the theory that early dopaminergic support for the degenerating dopaminergic system per se provides significant long-term clinical benefit for PD patients.     

Ethnic disparities in problem behaviour in adolescence contribute to ethnic disparities in social class in adulthood

BACKGROUND: It is important for prevention of social class disparities to know how ethnic disparities in social class arise among migrant children. We contribute to this understanding by examining the role of problem behaviour in adolescence. METHODS: Prospective observational study with 753 Dutch native and 217 Turkish migrant adolescents (11-18 year) followed for 10 years. Internalising and externalising problems were assessed in adolescence and employment status and occupational level were assessed in adulthood. The difference in odds ratios (OR) before and after adjustment for internalising and externalising problems was an indication of the predictive value of disparities in internalising and externalising problems for the development of social class disparities. RESULTS: A total of 135 (62%) of the Turkish and 602 (80%) of the Dutch adults were employed. Internalising and externalising problems were not associated with employment status. Of the employed, 65 (48%) Turkish and 179 (30%) Dutch adults worked in low-level occupations (p < 0.0001). Internalising and externalising problems were associated with both ethnicity and occupation. The OR for low-level occupation for Turkish adults was 1.78 (1.19-2.65), indicating ethnic disparities. Adjustment for internalising problems lowered the OR with 36% to 1.50 (0.97-2.31), and adjustment for externalising problems lowered it with 8% to 1.72 (1.15-2.57). Findings were similar for men and women and did not vary by age. CONCLUSIONS: Ethnic disparities in occupational level in adulthood could partly be attributed to disparities in mental health between Turkish migrants and Dutch natives in adolescence. Prevention of ethnic disparities in mental health at young age may therefore also contribute to the prevention of occupational differences in adulthood.