慢性应激对大鼠行为和免疫细胞热休克蛋白70表达的影响

目的：研究慢性不确定应激对大鼠急性整体热水浴后外周血和脾脏免疫细胞热休克蛋白70（Heat shock protein 70, HSP70）表达的影响。方法：随机将大鼠分成慢性应激组和控制组（每组14只）。通过4周的慢性不确定性应激诱发实验组大鼠明显的抑郁行为,此期间控制组大鼠正常饲养。随后给予大鼠42度整体热水浴刺激,维持直肠温度41度25min。热刺激后6h,采用流式细胞仪测定大鼠外周血和脾脏免疫细胞HSP70 水平。结果：与控制组大鼠相比,慢性应激大鼠在急性热刺激后HSP70合成明显减少。控制组大鼠的所有被检测的免疫细胞热应激后HSP70合成均明显增加。相反,慢性应激大鼠仅在外周血的单核细胞和粒细胞检测到HSP70合成增加,同时升高的水平明显低于控制组大鼠。结论：慢性应激降低大鼠免疫细胞HSP70的热诱导反应,提示HSP70保护性作用减弱可能参与了慢性应激损害免疫细胞功能的生物学过程     

慢性应激对大鼠海马Akt/FKHRL1信号通路活性的影响

探讨慢性应激对大鼠海马Akt/FKHRL1信号通路活性的影响,及其应激源特异性。将24只雄性SD大鼠随机分为心理应激组、束缚应激组和正常对照组（n=8）。用Western-blotting方法测定28天应激后海马Akt、FKHRL1蛋白含量及其磷酸化水平。结果表明,应激后三组大鼠海马磷酸化Akt、FKHRL1含量差异有统计学意义（p < 0.01;p < 0.001）,束缚应激组低于正常对照组（p < 0.01）。提示慢性应激能导致海马磷酸化Akt、FKHRL1表达水平降低,但其影响程度与应激源特异性有关     

慢性应激诱导的抑郁大鼠纹状体par-4基因的表达

为研究慢性温和应激诱导的抑郁大鼠纹状体内前列腺凋亡反应蛋白(prostate apoptosis response-4, par-4)的表达, 及甲基化是否参与par-4基因表达的调控, 将10周龄大鼠随机分为实验组和对照组, 实验组接受慢性温和应激, 对照组不接受实验性处理。于大鼠13周龄时, 采用强迫游泳、糖水偏爱测验测定大鼠的抑郁水平, 以实时定量PCR检测纹状体par-4及多巴胺D2受体(Dopamine receptor D2, DRD2) mRNA表达水平, 免疫印迹法检测纹状体par-4蛋白质表达水平, 用亚硫酸盐测序法检测par-4基因启动子区甲基化水平。结果发现, 与对照组大鼠相比, 实验组大鼠漂浮时间延长, 糖水偏爱率降低, 脑纹状体par-4、DRD2 mRNA及par-4蛋白质表达水平均降低, par-4基因启动子区甲基化水平两组差异不显著。提示慢性温和应激诱导大鼠产生了抑郁样行为, 并能抑制纹状体par-4基因的表达, 而基因甲基化可能并不参与其调控机制。     

应激性抑郁样行为发生中海马5-羟色胺1A受体的作用及其对NMDA受体和AMPA受体的调节

为探讨慢性不可预见性温和应激(chronic unpredictable mild stress, CUMS)诱发抑郁样行为发生中海马5-羟色胺1A受体(5-hydroxytryptamine receptor 1A, 5-HT1AR)表达与作用, 及其对谷氨酸N-甲基-D-天冬氨酸(N-methyl-D-aspartic acid, NMDA)受体和α-氨基羟甲基异恶唑丙酸(α-amino-3-hydroxy-5- methylisoxazole-4-propionic acid, AMPA)受体的影响。通过建立CUMS动物模型, 给应激抑郁模型大鼠海马微量注射5-HT1A受体激动剂、给正常大鼠海马微量注射5-HT1A受体拮抗剂, 测量大鼠体重变化率, 并采用糖水偏爱测试、旷场实验和悬尾实验等方法对大鼠进行行为学检测, 运用Western blot和ELISA方法检测大鼠海马组织中5-HT1AR和NMDAR和AMPAR的关键亚基的表达以及磷酸化水平。结果显示, 与对照组相比, CUMS组大鼠表现出抑郁样行为, 海马5-HT1AR、AMPA受体的GluR2/3亚基表达及磷酸化明显降低, NMDA受体的NR1和NR2B亚基表达及磷酸化显著增加; 正常大鼠海马微量注射5-HT1A受体拮抗剂WAY100635, 动物行为学表现及AMPA受体、NMDA受体表达及磷酸化水平均与CUMS组相同; 注射5-HT1A受体激动剂8-OH-DPAT能逆转应激诱导的上述改变。以上结果表明, CUMS诱发抑郁样行为与海马5-HT1AR表达下降, AMPAR表达量及磷酸化水平降低, NMDAR表达量及磷酸化水平升高有关。5-HT通过5-HT1AR产生抗抑郁作用。5-HT1AR激动剂抗抑郁作用与降低NMDAR表达量及磷酸化水平, 提高AMPAR表达量及磷酸化水平密切相关。     

慢性强迫游泳应激对大鼠情绪和脑细胞外信号调节激酶的影响

为探讨慢性强迫游泳应激对动物情绪和脑组织细胞外信号调节激酶（extracellular signal-regulated kinase, ERK1/2）的影响,动物情绪和脑组织ERK1/2之间的关系,将动物随机分为游泳应激组、装置对照组和控制组。分别对三组大鼠给予相应的干预14天, 然后进行行为观察,免疫印记法测定海马和前脑皮质ERK1/2水平。结果表明强迫游泳应激组和装置对照组都出现明显的情绪障碍。两组大鼠ERK1/2在前脑皮质的表达水平均显著升高,海马无显著变化。前脑皮质ERK2与糖精水摄入量呈显著负相关。提示慢性强迫游泳应激能够诱导大鼠的情绪障碍,提高ERK1/2在前脑皮质的表达水平,ERK1/2与情绪关系密切,可能是脑组织应激性情绪调节的重要生理机制。强迫游泳应激能够导致动物明显的抑郁反应,是比较理想的抑郁动物模型     

慢性束缚应激对大鼠脑内Fas、FasL含量的影响

为探讨慢性束缚应激对大鼠脑内不同部位Fas/FasL系统表达的不同影响。将24只雄性SD大鼠随机分为束缚应激组、装置对照组和正常对照组（n=8）。分别对三组大鼠给予相应的干预14天,用Western-blotting方法测定应激后大鼠大脑前脑皮质、内嗅皮质以及海马区域Fas、FasL蛋白含量。结果表明,应激后各脑区三组大鼠Fas含量差异具有统计学意义（p < 0.01）,束缚应激组明显高于正常对照组或装置对照组（p < 0.01）。在海马区域,三组大鼠FasL含量差异具有统计学意义（p < 0.01）,束缚应激组大鼠FasL蛋白水平显著高于正常对照组或装置对照组(p < 0.01)。三组大鼠自身大脑前脑皮质、内嗅皮质以及海马Fas含量的差异比较均无统计学意义( p > 0.05) 。束缚应激组大鼠海马的FasL含量高于前脑皮质和内嗅皮质(p < 0.05);正常对照组或装置对照组自身不同脑区间FasL含量的变化无统计学意义。提示慢性束缚应激能诱导大鼠脑内Fas/FasL系统表达水平的改变,对不同的脑区,其影响程度明显不同     

不同时程应激对大鼠行为、免疫和交感神经系统反应的影响

研究旨在研究不同时程情绪应激诱导的大鼠行为、免疫和神经内分泌反应的动态变化及其相互关系。实验采用一种在程序性饮水的固定时间点不确定性给予大鼠空瓶刺激诱发其情绪反应的应激模式,测定不同时程（14,21和28天）应激对大鼠行为、交感神经系统反应、体液免疫功能及体重增长的影响。结果表明,情绪应激导致大鼠攻击行为显著增加,且在整个应激过程中情绪应激组大鼠的攻击行为都被稳定地诱导;不同时程的情绪应激均导致大鼠特异性抗OVA抗体水平明显降低,且降低的程度类似;在情绪应激的第14天和28天应激组大鼠血中去甲肾上腺素水平明显高于对照组,但后者升高的水平明显低于前者。此外,14天应激明显抑制大鼠的体重增长,但随着应激时程的延长,体重增长逐渐恢复。这些结果表明,随着应激时程的延长,大鼠行为、免疫和神经内分泌反应的适应性改变存在时程差异,有助于进一步了解应激诱发的各种反应间的复杂关系     

强迫性冷水游泳应激对大鼠行为和海马神经颗粒素的影响

为考察应激对海马神经颗粒素含量和磷酸化水平的影响,以及神经颗粒素是否涉及应激所致行为效应的脑机制,采用强迫性冷水游泳应激模型,选取40只Sprague-Dawley大鼠,随机分为应激组、装置对照组和正常对照组1和正常对照组2。以旷场试验法测定应激前后大鼠行为的变化,以Western blotting技术测定大鼠海马区域神经颗粒素的总含量和磷酸化水平,并分析两者之间的相互关系。结果表明：应激组动物活动增加,表现出焦虑行为;而海马区域神经颗粒素含量降低,与对照组相比差异具有显著性;且多项行为指标的变化与海马神经颗粒素含量的改变呈显著相关。这些结果提示神经颗粒素有可能在应激所致焦虑行为中起作用,可作为预测应激所致焦虑行为的较为敏感的指标之一。慢性应激过程中海马区域没有发现神经颗粒素的磷酸化反应。     

不同应激范式对大鼠行为和脑神经颗粒素含量的影响

为探讨慢性情绪应激、生理应激对大鼠旷场行为和脑神经颗粒素（Neurogranin,NG）含量的不同作用,以及NG含量变化与应激性行为效应之间的相互关系。分别以不确定性空瓶刺激和饮水剥夺,建立情绪应激和生理应激动物模型。将40只雄性SD大鼠随机分为情绪应激组（ES）、生理应激组（PS）、定时饮水组（C1）和正常对照组（C2）（n=10）。以旷场行为任务来评定大鼠应激后的行为变化,Western blotting方法测定海马和前脑皮层中的NG含量。结果表明：应激后四组大鼠海马的NG含量差异无显著性;ES组前脑皮层的NG含量低于C2组,差异具有显著性,p<0.01;PS组的前脑皮层NG含量也下降,但与C2组相比差异无显著性; 应激后ES组、PS组修饰行为多于C2组,差异具有显著性,分别为p<0.01,p<0.05;前脑皮层NG含量与修饰行为之间的相关达显著水平。提示慢性情绪和生理应激均能导致前脑皮层NG含量下降,修饰行为增加,情绪应激作用更显著。修饰行为可能是反映情绪状态的较敏感行为指标,前脑皮层NG水平可能是预测情绪应激所致焦虑或抑郁行为的较敏感生物学指标。     

恐惧发生与预防的实验研究：──Ⅰ、强烈噪音下恐具行为的动物模型

通过不同方法对ＳＤ型大鼠分四组进行实验处理,观察比较大鼠的行为,发现：在突然的高强度噪音条件下,大鼠出现恐惧的行为反应;强刺激组大鼠恐惧行为较控制组明显增多,行为的唤醒适应能力异常,并存在显著的个体差异;噪音脱敏训练对提高大鼠在高强噪音条件下的应激能力、减少恐惧具有良好的促进作用;在脱敏训练中尤以逐渐递增噪音强度、刺激时间与平均分配实验日结合的方法效果最为显著。     

Differential effects of physical and psychological stressors on immune functions of rats

To study the effects of different types or durations of stressors on immune functions, male Fischer rats were exposed to chronic physical (electric foot shock) or psychological (non-foot shock) stress induced in the communication box. Superoxide production by alveolar macrophages (AMs), mitogen-induced splenic lymphocyte proliferation, and splenic natural killer (NK) cell cytolysis were examined in vitro. Repeated exposure to physical stress suppressed superoxide production by AMs (-58%, p<0.05 for opsonized zymosan (OZ) and -51%, p<0.05 for phorbol 12-myristate 13-acetate (PMA)), although psychological stress suppressed superoxide production after 24 h of repeated exposures (-40%, p<0.05 for OZ and -47%, p<0.05 for PMA). Acute suppression of the blastic response of splenic lymphocytes was only found in the physical stress group (p<0.05), although the chronic effects were only found in the psychological stress group (p<0.05). NK cell activity was suppressed immediately after the acute physical stress (-30%, p<0.05), but no effects were found in the psychological stress group. These results underline the importance of distinguishing between physical versus psychological stressors when examining the effects of stress on immune functions.     

Tumor necrosis factor-associated protein 1 (TRAP-1) protects cells from oxidative stress and apoptosis

TRAP-1 is a mitochondrial heat shock protein (HSP), recently identified in Saos-2 osteosarcoma cells adapted to mild oxidative stress induced by diethylmaleate (DEM). TRAP-1 mRNA expression is increased in DEM-adapted cells as well as in tumor cells resistant to 5-fluorouracil and to platin derivatives. Since a strong decrease of TRAP-1 protein levels, upon cisplatin treatment, is observed only in controls but not in the DEM-adapted counterpart, a possible role for this protein in the development of resistant phenotypes could be hypothesized. To characterize the protective role of TRAP-1 against oxidative stress and apoptosis, stable transfectants were generated and characterized for their response to different stress types. These stable clones expressing constitutively high TRAP-1 levels: (i) are more resistant to H2O2-induced DNA damage and to apoptosis by cisplatin; (ii) contain higher reduced glutathione (GSH) levels than control cells; and (iii) do not release the apoptosis-inducing factor into the nucleus upon cisplatin treatment. Furthermore, high TRAP-1 levels interfere with caspase 3 activation. These results confirm the anti-apoptotic role of TRAP-1, and suggest that increased expression of this mitochondrial HSP in DEM-adapted and chemoresistant cells could be part of a pro-survival signaling pathway aimed to evade toxic effects of oxidants and anticancer drugs.     

Glucocorticoid receptor interaction with Hsp90 remains unaltered after whole body hyperthermia

The influence of 41 degrees C whole body hyperthermic stress on glucocorticoid receptor (GR) association with 90-kDa heat shock protein (Hsp90) in the rat liver cytosol was examined. Total cytosolic GR and Hsp90 concentrations, as well as the amount of Hsp90 co-immunoprecipitated with the GR were determined by quantitative Western blotting using BuGR2 as anti-GR and AC88 as anti-Hsp90 monoclonal antibody. After exposure of the animals to the heat stress, the level of cytosolic Hsp90 increased, while its ratio to apo-receptor within non-activated GR heterooligomeric complexes remained unaltered. Therefore, the Hsp90 recruitment by the GR was not dependent on Hsp90 total cytosolic concentration.     

Learning associated increase in heat shock cognate 70 mRNA and protein expression

The Morris water maze is a task widely used to investigate cellular and molecular changes associated with spatial learning and memory. This task has both spatial and aversive (swimming related stress) components. It is possible that stress may influence cellular modifications observed after learning the Morris water maze spatial task. Heat shock proteins, also known as stress proteins, are up-regulated in response to thermal stress, trauma, or environmental insults. In the rat hippocampus, psychophysiological stress increases the levels of heat shock protein 70 (HSC70). In this study, we investigated whether the expression of the hsc70 gene is modulated in the hippocampus during learning of the Morris water maze task. Five groups of rats were trained in the Morris water maze task for varying amounts of time (either 1, 2, 3, 4, or 5 days). Training consisted of 10 trials/day in which the animals were given 60s to find a submerged platform. Rats were sacrificed 24h after their last training trial. Results showed a significant increase in hsc70 mRNA and protein levels in the hippocampal formation after two and three days of training, respectively. The increase in mRNA and protein was associated with learning but not stress because the increase was not observed in the yoked control animals. These findings suggest that cellular and molecular changes can occur independent of stress. Moreover, the results are the first to implicate hsc70 expression in spatial learning.     

心理解脱与幼儿教师生活满意度的关系：家庭压力的调节作用

下班后从工作状态中解脱出来有利于减少工作应激对劳动者健康的损害。家庭作为劳动者下班后生活的主要场所。家庭中的压力因素可能影响劳动者的解脱结果。本研究以 215 名幼儿教师为被试，考察家庭压力影响心理解脱结果的机制。结果发现，高家庭压力会削弱心理解脱对生活满意度的正向预测。该结果支持资源保持理论和付出-恢复模型，提示在工作应激相关的职业健康保护中应注意家庭因素的作用。     

急性心理应激影响记忆效果：心理韧性的调节作用

研究选取56名大学生被试,通过特里尔社会应激测验、记忆和心理韧性测验来探究急性心理应激对大学生记忆效果的影响,以及心理韧性在二者关系中的调节作用。结果表明相对于非应激组,应激组大学生的整体记忆成绩更差,且应激组中的高应激反应大学生的记忆成绩比低应激反应者的记忆成绩更差;心理韧性可以调节应激反应与记忆成绩之间的关系,表现为高心理韧性者的记忆成绩显著好于低心理韧性者。研究进一步从认知加工资源分配与再分配的视角讨论了心理应激、心理韧性与记忆功能三者间的关系与启示。     

Exposure to acute physical and psychological stress alters the response of rat macrophages to corticosterone, neuropeptide Y and beta-endorphin

The objective of the present study was to investigate the effect of acute exposure to electric tail shock stress (ES) and a stress witnessing procedure (SW), as models for physical and psychological stress paradigms, respectively on adherence, phagocytosis and hydrogen peroxide (H(2)O(2)) release from rat peritoneal macrophages. In addition, we studied the in vitro effects of corticosterone (CORT), neuropeptide Y (NPY) and beta-endorphin (BE) on adherence, phagocytosis and H(2)O(2) release from macrophages isolated from control rats and from rats that had been exposed to ES or SW procedures 24 h earlier. ES and SW comparably diminished phagocytosis and H(2)O(2) release, but did not influence macrophage adherence. In vitro treatment with CORT and NPY notably suppressed phagocytosis and potentiated H(2)O(2) release from macrophages. BE suppressed both phagocytosis and H(2)O(2) release from macrophages. Previous exposure to ES and SW altered the responsiveness of the isolated macrophages to their in vitro treatment with mediators of stress, making the cells less sensitive to the influence of CORT and NPY and to a lesser extent to BE. It could be concluded that changes in the local macrophage milieu induced by ES and SW 24 h earlier modify macrophage responses to subsequent in vitro exposure to the stress mimics, CORT, NPY and BE.