慢性应激性抑郁发生中海马糖皮质激素对BDNF的影响

为证明慢性应激性抑郁的发生与应激引起的糖皮质激素(Glucocorticoids,GCs)分泌增加,导致海马脑源性神经营养因子(Brain Derived Neurothrophic Factor,BDNF)表达抑制有关.实验用大鼠通过建立慢性不可预见性温和应激(Chronic Unpredictable Mild Stress,CUMS)抑郁模型,通过海马微量注射皮质酮及糖皮质激素受体拮抗剂米司非酮,然后测量体重,观测行为学表现,并用酶联免疫吸附法检测海马内GCs和BNDF含量.结果显示:CUMS明显诱发大鼠抑郁样行为,海马组织中皮质酮明显升高,BDNF水平明显下降.海马微量注射米司非酮,使CUMS诱发的大鼠抑郁样行为明显改善,且BDNF水平明显升高.正常大鼠海马微量注射皮质酮后,表现出与CUMS组相似的抑郁样行为,且海马组织中BDNF明显下降.以上结果表明,慢性应激引起大鼠海马皮质酮明显升高,使海马BDNF表达明显减少,导致抑郁发生.糖皮质激素Ⅱ型受体(Glucocorticoids Receptor,GR)起着重要作用.     

转化生长因子-β1与硒蛋白P在慢性应激性抑郁发生中的作用及关系

为了研究慢性应激性抑郁发生中海马转化生长因子β1(transforming growth factor beta–1,TGF-β1)和硒蛋白P的作用及其关系,实验通过建立慢性不可预见性温和应激(Chronic Unpredictable Mild Stress,CUMS)动物抑郁模型,同时海马内微量注射TGF-β1以及TGF-β1型受体激酶抑制剂LY-364947,然后测量大鼠体重变化率,并通过糖水消耗以及旷场实验、悬尾实验检测大鼠行为变化,运用Elisa、Western blot分别检测大鼠海马组织内TGF-β1和硒蛋白P的含量变化.结果显示,与正常对照组相比,CUMS组大鼠表现出明显的抑郁样行为,海马组织内TGF-β1含量升高,硒蛋白P表达下降;正常大鼠海马内注射TGF-β1并不导致抑郁样行为,相反,CUMS同时海马内注射TGF-β1能逆转应激导致的抑郁样行为;正常和CUMS大鼠海马注射TGF-β1均能明显抑制硒蛋白P的表达;而应激的同时注射TGF-β1型受体激酶抑制剂LY-364947同样具有抗抑郁效应,此时硒蛋白P表达较CUMS组明显升高.以上结果表明:海马TGF-β1和硒蛋白P参与了应激性抑郁的发生;硒蛋白P对海马可能具有保护作用,TGF-β1通过TGF-β1型受体抑制硒蛋白P表达可能是导致抑郁发生的途径之一,而TGF-β1抗抑郁作用可能是经过TGF-β1型受体以外的其他途径实现.     

跑台运动对抑郁模型大鼠学习记忆及海马CA1区BDNF表达的影响

目的：观察4周跑台运动对慢性应激致抑郁大鼠空间学习记忆能力,血浆皮质醇（Cortisol,cort）含量和海马CA1区脑源性神经营养因子（Brain Derived Neurotrophic Factor,BDNF）表达的影响.方法：30只SD大鼠随机分为正常对照组、应激模型组及应激运动组,制作慢性不可预见性应激模型,用八臂迷宫实验观察各组大鼠学习记忆等行为学指标的变化,放射免疫法测试大鼠血浆cort含量,免疫组织化学结合图像半定量方法对海马CA1区BDNF神经元的数量及面积进行测量和分析.结果：慢性应激致抑郁大鼠血浆cort含量增加,八臂迷宫实验中应激大鼠完成八臂迷宫时间显著延长,工作记忆错误次数、参考记忆错误次数及总记忆错误次数均显著增加,海马CA1区BDNF表达减弱.而长期跑台运动可以显著改善抑郁模型大鼠的学习记忆能力,血浆cort含量降低,海马CA1区BDNF表达增强.结论：跑台运动可改善抑郁模型大鼠的学习记忆能力,机理可能与长期运动降低抑郁大鼠的血浆cort水平、拮抗HPA轴功能亢进及增强海马CA1区BDNF的表达有关.     

坚果改善慢性应激致抑郁症大鼠行为学表现及其机制研究

为探讨坚果(核桃与甜杏仁)在抑郁症中的预防作用和机制.采用慢性温和不可预测应激(CMS)大鼠模型模拟抑郁症,对大鼠进行强迫游泳(FST)、糖水消耗的抑郁症行为学测试,并运用ELISA 试剂盒测定大鼠血浆皮质酮(CORT)含量,Western blot 法检测大鼠海马部脑源性营养因子(BDNF)、蛋白激酶A(PKA)和蛋白激酶C(PKC)的蛋白表达.实验结果表明,模型组FST、糖水消耗的行为学成绩明显低于正常对照组(P＜0.05),预先给予坚果各剂量(60 g·kg－1、120 g·kg－1、240 g·kg－1),可改善抑郁症大鼠的行为学成绩,提示,食用坚果可延缓抑郁症症状.血浆CORT水平测定结果显示,模型组血浆CORT含量显著高于正常对照组(P＜0.05),但坚果各剂量组对血浆CORT含量无影响(P＞0.05),提示,坚果产生延缓抑郁发生的机制可能与作用CORT途径无关联.对大鼠海马部的BDNF、PKA和PKC蛋白表达测定显示,模型组BDNF、PKA和PKC的蛋白表达均低于正常对照组(P ＜ 0.05),而经预先给与坚果的各剂量坚果组,则拮抗了模型组BDNF、PKA和PKC蛋白表达水平的下降(P＜0.05).提示,坚果在预防抑郁症作用机制可能与激活PKA、PKC激酶和增强BDNF蛋白水平的信号通路有关.因此,本实验结果初步明确,预先食用坚果可有助于延缓抑郁症的产生.这将为后续食用坚果类食物在预防抑郁症中的研究提供了一定的理论和实验依据.     

雌激素受体α在抑郁症模型大鼠海马中的分布

观察雌激素受体α(ERα)在正常大鼠和抑郁症模型大鼠海马中的分布.采用慢性不可预见性应激结合孤养方式构建抑郁症模型,Open-field法观察动物的抑郁行为,免疫组织化学方法观察海马神经元中ERα的分布.结果表明:与对照组相比,抑郁组大鼠水平运动、垂直活动和理毛次数显著减少(P0.01),体重增幅和糖水消耗量显著性下降(P0.01);在对照组和抑郁组,ERα免疫反应阳性神经元主要分布在海马的锥体层和颞叶皮层,DG区较少;与对照组相比较,抑郁组海马中ERα免疫阳性细胞数和染色强度均明显减少和降低;在对照组ERα染色主要位于神经元的胞核、胞质和/或突起,在抑郁组ERα染色主要位于神经元的胞质和突起,而位于胞核的则很少见.抑郁症的雌激素功能缺失或弱化机制,可能是应激诱导抑郁症过程中导致雌激素通过ERα核受体信号通路发挥神经保护作用的能力减弱.     

AQP-4在抑郁模型大鼠海马区含量的改变

目的探讨抑郁模型大鼠海马区AQP-4含量的改变.方法通过采用慢性不可预见性刺激和孤养相结合的方法,在应激前1天和应激第22天后对大鼠行为学观测,快速断头取海马组织,通过半定量PCR方式观察海马区AQP-4含量的变化.结果发现抑郁大鼠海马区AQP-4mRNA的相对含量增加.结论 AQP-4既参加调节抑郁模型大鼠海马区内环境,同时对抑郁模型大鼠海马区神经元的凋亡发挥作用,为研究抑郁症的发病机制奠定基础.     

芒果苷通过作用于NLRP3炎症小体发挥抗抑郁和神经保护作用

研究了芒果苷对慢性不可预测性轻度应激抑郁症大鼠的治疗作用以及作用机制.大鼠随机给予不可预测性刺激,连续6周,制备抑郁症模型.实验组在第4至第6周给予芒果苷(MGF,20、40、80 mg/kg)灌胃治疗,氟西汀(Flu, 10 mg/kg)灌胃作为阳性对照.实验结束时对大鼠大脑进行生化分析、组织病理学检查以及炎症小体相关蛋白表达,检测大鼠血清中相关炎症因子蛋白的表达.实验表明MGF对慢性不可预测的轻度应激(CUMS)诱导的大鼠抑郁症行为有明显的改善作用;MGF可以抑制CUMS大鼠NLRP3、Caspase-1和ASC蛋白以及mRNA的表达水平;抑制CUMS大鼠血清中相关炎症因子的蛋白表达水平;MGF同时可以降低NLRP3炎症小体的表达水平,缓解CUMS引起的大脑病理损害,对CUMS大鼠引起的脑损伤起到保护作用.     

安神方颗粒对CUMS大鼠递质代谢与炎症反应的影响

目的:探讨安神方颗粒对慢性应激抑郁模型大鼠行为学以及递质代谢和炎症反应的影响.方法:30只Wistar大鼠随机分为空白组、模型组、安神方颗粒组,每组10只;除空白组外,其余各组大鼠进行2周的慢性温和不可预知应激(CUMS)刺激;在后续3周进行CUMS 1 h前,安神方颗粒组每天给予安神方颗粒质量分数40 g/kg灌胃,空白组和模型组给予等体积生理盐水灌胃.观察各组大鼠治疗前后的体质量变化;运用强迫游泳(FST)和糖水偏好实验(SPT)评估大鼠抑郁行为的变化;通过ELISA法检测大鼠海马组织中炎症因子白细胞介素-1β(IL-1β)和肿瘤坏死因子-α(TNF-α)的含量,并通过Western blotting和免疫荧光检测大鼠海马BDNF和GABA_ARα2表达情况.结果:与空白组比较,模型组大鼠体质量增加缓慢(P 0. 01),FST累积不动时间明显延长(P 0. 01),糖水偏好值减少(P 0. 01),海马BDNF和GABA_ARα2表达水平下降(P 0. 01);与模型组比较,安神方颗粒组大鼠体质量增长较快(P 0. 01),FST累积不动时间明显缩短(P 0. 01),糖水偏好值升高(P 0. 01),海马组织中炎症因子IL-1β和TNF-α的含量降低,BDNF和GABA_ARα2表达水平上升(P 0. 01).结论:安神方颗粒可能参与干预炎症因子IL-1β和TNF-α上调海马组织BDNF和GABA_ARα2的表达,从而发挥抗抑郁的作用.     

慢性束缚应激性抑郁与雌性小鼠雌激素和海马雌激素受体的关系

采用慢性束缚应激抑郁模型,通过强迫游泳测试(Forced swimming test,FST)和免疫组织化学方法,探讨了慢性束缚应激对雌性小鼠海马雌激素受体(Estrogen receptor,ER)和行为表现的影响.结果显示:与对照组相比,慢性束缚应激小鼠的体重降低或增长速度明显减慢,FST不动时间增长(P＜0.01),ER表达下降(P＜0.01);卵巢切除后的小鼠在行为表现和ER表达与慢性束缚应激组的结果相似;与应激组相比,应激同时周期性外源补充雌激素,小鼠体重增长速度加快,FST不动时间明显减少(P＜0.01),而ER表达明显下降(P＜0.01).结果表明,慢性束缚应激能诱发抑郁,慢性束缚应激性抑郁发生与雌激素水平及雌激素受体下降有关.     

自愿转轮运动对抑郁模型大鼠学习记忆能力及海马齿状回一氧化氮合酶表达的影响

目的：观察4周自愿转轮运动对慢性应激致抑郁大鼠绝望行为及空间学习记忆能力和海马DG区nNOS表达的影响.方法：30只SD大鼠随机分为对照组、应激模型组及应激运动组,应激模型组及应激运动组大鼠建立慢性不可预见性应激（chronic unpredictable mild stress,CUMS）抑郁模型,同时应激运动组大鼠进行4周自愿转轮运动.运动及应激结束后通过强迫游泳实验及八臂迷宫实验等方法测试大鼠行为学指标变化,免疫组织化学法检测大鼠海马DG区nNOS神经元的表达.结果：（1）与对照组相比,慢性应激致抑郁大鼠强迫游泳实验中大鼠不动时间延长,八臂迷宫实验中应激大鼠完成八臂迷宫时间显著延长,工作记忆错误次数、参考记忆错误次数及总记忆错误次数均显著增加;海马DG区nNOS表达显著增强.（2）与应激模型组比较,应激运动组大鼠强迫游泳实验中大鼠不动时间缩短,八臂迷宫实验中应激运动组大鼠完成八臂迷宫时间显著缩短,参考记忆错误次数及总记忆错误次数均显著减少,海马DG区nNOS表达减弱.结论：自愿转轮运动可改善抑郁模型大鼠的绝望行为、提高大鼠学习记忆能力,机理可能与长期自愿转轮运动减弱抑郁大鼠海马DG区nNOS表达导致NO神经毒性减弱有关.     

产前应激子代大鼠海马可塑性改变诱导抑郁样行为的发生

研究旨在探索海马可塑性改变在产前应激(PS)子代大鼠抑郁样行为中的作用。通过建立大鼠产前束缚应激模型,采用强迫游泳实验检测子代大鼠的抑郁样行为,快速Golgi染色观察海马CA1区锥体细胞顶树突的树突棘密度,Western-blotting检测海马脑源性神经营养因子(BDNF)的表达。结果发现,与对照组相比较,PS组雌、雄子代大鼠强迫游泳实验(FST)中的不动时间均明显增加,有统计学差异(P0.05),而且PS组雌性子代大鼠的不动时间较雄性子代更加延长(P0.05)。PS组雌、雄子代大鼠海马CA1区锥体细胞的顶树突棘密度均较对照组显著减少(P0.05),PS组雌、雄子代之间无统计学差异。PS组雌、雄子代大鼠海马的BDNF表达均较对照组显著减少(P0.05),PS组雌、雄子代之间亦无显著性差异。这些结果说明海马CA1区锥体细胞的树突棘密度减少和海马BDNF表达减少参与PS导致的子代大鼠抑郁样行为的发生。     

海洋胶原肽改善老年记忆作用试验研究

为探讨海洋胶原肽(MCP)对老年学习记忆的改善作用及其机制,选用20月龄雌性C57BU6J小鼠,随机分为老年对照组和3个MCP干预组,分别喂饲添加0、0.22%、0.44%和1.32%MCP的特殊加工饲料.另设3月龄青年对照组,喂饲普通小鼠生长饲料,干预6个月后应用跳台试验和Morris水迷宫试验进行行为学检测:nissl染色观察海马形态学;同时检测各组动物肝脏中超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量及海马组织中脑源性神经营养因子(BDNF)的表达情况.结果表明,MCP干预后老龄小鼠的空间学习记忆能力和被动回避能力明显提高;0.44%MCP干预组小鼠肝脏SOD活性显著高于老龄对照组,而MDA含量显著降低;0.44%和1.32%MCP干预组小鼠海马区BDNF的表达高于老年对照组.各组动物海马神经元数量无明显改变.因此,海洋胶原肽具有预防年龄造成的学习记忆能力下降的功能.其作用机制可能是抗氧化活性和促进BDNF的表达.     

Effects of niacin on nitric oxide synthase expression in rat lungs exposed to silica

The aim of this study was to evaluate the effects of niacin in diet on the expression of nitric oxide synthase (NOS) in rat lungs of the animal model of silicosis established by direct tracheal instillation of silica particles into rat lungs surgically. The niacin concentration in serum was analyzed by high performance liquid chromatography (HPLC). The expression of inducible nitric oxide synthase (iNOS) protein in paraffin-embedded lung sections was determined by streptavidin/peroxidase (SP) staining. Quantitative analysis by Image-Pro Plus was also performed on the expression of iNOS. The results showed that niacin concentration in serum of the niacin-treated rats was significantly higher than that in the control and silica-treated rats. After 7 days of silica instillation, iNOS integrated optical density (IOD) in rat lungs and total NOS and iNOS activities in bronchoalveolar lavage fluid (BALF) in silica-treated rats rose by 273420.75, 2.61 units/mL and 1.89 units/mL respectively, when compared with those in the control rats. Niacin treatment significantly reduced silica-induced iNOS IOD in rat lung tissues and total NOS and iNOS activities in BALF supernatant by 248292.35, 1.50 units/mL and 0.91 units/mL, respectively, as compared with those in silica-treated rats. Therefore, niacin can effectively attenuate the pathological expression of NOS in rat lung tissues induced by silica particles.     

红参松花粉片对阿尔茨海默症大鼠空间学习记忆能力及海马神经细胞凋亡的影响

通过Aβ25-35 联合D-半乳糖诱导,建立实验性大鼠阿尔茨海默症 (Alzheimer’s disease,AD)模型,采用Morris水迷宫实验,评估红参松花粉片对AD模型大鼠学习记忆能力和海马神经细胞凋亡的影响．同时,运用Western blot、RT-qPCR及TUNEL法,检测AD模型大鼠海马神经细胞中BCL2、BAX、p-AKT及p-GSK3β的含量．研究表明:与模型组相比,红参松花粉片高剂量组能显著缩短模型大鼠逃脱潜伏期和游泳距离 (P<0.05),显著增加搜索时间百分比 (P<0.05);红参松花粉片高、低剂量给药组上调了AD模型大鼠海马神经细胞中Bcl-2、p-AKT及p-GSK3β的表达,下调了BAX的表达,显示AD模型大鼠海马神经细胞凋亡过程明显减缓,说明红参松花粉片能改善AD模型大鼠学习记忆的能力,对海马神经凋亡起到了一定的抑制作用．      

Essential role of TRPC channels in the guidance of nerve growth cones by brain-derived neurotrophic factor

Brain-derived neurotrophic factor (BDNF) is known to promote neuronal survival and differentiation and to guide axon extension both in vitro and in vivo. The BDNF-induced chemo-attraction of axonal growth cones requires Ca2+ signalling, but how Ca2+ is regulated by BDNF at the growth cone remains largely unclear. Extracellular application of BDNF triggers membrane currents resembling those through TRPC (transient receptor potential canonical) channels in rat pontine neurons and in Xenopus spinal neurons. Here, we report that in cultured cerebellar granule cells, TRPC channels contribute to the BDNF-induced elevation of Ca2+ at the growth cone and are required for BDNF-induced chemo-attractive turning. Several members of the TRPC family are highly expressed in these neurons, and both Ca2+ elevation and growth-cone turning induced by BDNF are abolished by pharmacological inhibition of TRPC channels, overexpression of a dominant-negative form of TRPC3 or TRPC6, or downregulation of TRPC3 expression via short interfering RNA. Thus, TRPC channel activity is essential for nerve-growth-cone guidance by BDNF.     

Inducible nitric oxide synthase expression is related to angiogenesis,bcl—2 and cell proliferation in hepatocellular carcinoma

In this study,we examined the expression of inducible nitric oxide synthase(iNOS) and vascular endothelial growth factor(VEGF) by immunohistochemical staining in 76 tissue sections collected from bepa-tocellular carcinoma(HCC) patients undergoing hepatectomy.Microvascular density (MVD) was determined by counting endothelial cells immunostained using anti-CD34 antibody.We performed DNA-flow cytometric analyses to elucidate the impact of iNOS and VEGF expression on the cell cycle of HCC.Most of the HCC cells that invaded stroma were markedly immunostained by iNOS antibody.The iNOS stain intensity of the liv-er tissue close to the tumor edge was stronger than that of HCC tissue,and the strongest was the hepatocytes colser to the tumor tissue.However,iNOS expression in 10 normal hepatic samples was undetectable.VEGF positive expression ratio was 84.8% in iNOS positive expression cases,and the ratio was 35.3% in negative cases.There was significant correlation(P=0.000) between iNOS and VEGF expression.Moreover,iNOS expression was significantly associated with bcl-2 and MVD,but without p53 expression.DNA-flow cytometric analyses showed that combined expression of iNOS and VEGF had significant impact on the cell cycle in HCC.PI(Proliferating Index) and SPF(S-phase fraction)in the combined positive expression of iNOS and VEGF group was significantly higher than that in the combined negative group.The present findings suggested that iNOS expression was significantly associated with angiogenesis,bcl-2 and cell proliferation of HCC.     

Neurotrophic regulation of synapse development and plasticity

Neurotrophic factors are traditionally thought to be secretory proteins that regulate long-tern survival and differe, ntiation of neurons. Recent studies have revealed a previously unexpected role for these factors in synaptie de velopment ami plasticity in diverse neuronal populations. Here we review experimeuts carried oul in our own laboratory in the last few years.. We have made two important discoveries.First,we were among the first to report that brain-derived. neurotrophie faclor (BDNF) facilitates hippocampal hmg-term potentiation (LTP), a form of synaptic plaslicity believed to be involved in learning and memory. BDNF modulates LTP al CAI synapses by enhaneing synaptic responses to high frequency, tetanic slimulalion. This is achieved primafily by facilitating synaptie vesicle doeking, possibly due to an in crease in the levels of the vesicle prolein synaptobrevin and synaptoplysin in the nerve terminals. Gene knockout study demonstrates thai the effects of BDNF are primarily mediated through presynaptic mechanisms. Second, we demonstrated a form of long-term, neurotrophin-mediated synaptic regulation. We showed that long-term treatment of the neuromuscu lar synapses with neurotrophin-3 (NT3) resulted in an enhancement of both spontaneous and evoked synaptic currcuts, as well as profound changes in thc number of synaptic varicosities and syuaptic vesicle proteins in motoneurons, all of which are indicative of more mature synapses. Our current work addresses the following issues:(i) activity-dependent trafficking of neurotrophin receptors, and its role in synapse-specific modulation; (ii) signal transduction mechanisms medialing the acute enhancement of synaplic transmission by neurotrophins; (iii) acute and long-tenn synaptie actions of the GDNF family; (iv) role of BDNF in late-phase LTP and in the development of hippocampal circuit.