电针对帕金森病模型大鼠黑质TNF-α、IL-1β表达的影响

目的:探讨电针治疗帕金森病(PD)的作用机制.方法:取SD大鼠50只,随机分为正常组、假手术组、模型组和电针组.电针组针刺“风府”“太冲”,每日1次,共治疗2周,其它组不予治疗干预.以6-羟基多巴胺制备PD大鼠模型.采用免疫组织化学法观察黑质酪氨酸羟化酶(TH)、肿瘤坏死因子α( TNF-α)和白细胞介素1 β(IL-...     

细胞内钙离子在高温诱导海马神经元凋亡中的作用机制

目的探讨Ca2+在高温诱导海马神经元凋亡中的作用,为丹曲林钠在热致脑损伤疾病中的应用提供实验依据。方法通过体外建立高温诱导原代培养的海马神经元凋亡模型,应用Ca2+特异性阻断剂丹曲林钠,观察其对神经元凋亡率、细胞内Ca2+荧光强度及其动态变化的影响。结果丹曲林钠能够明显降低高温处理后海马神经元的凋亡率;42℃处理并加入丹曲林钠组的扫描结果显示,Ca2+荧光强度为107.35±6.0,较正常培养的细胞内Ca2+荧光强度(159.12±33.8)明显降低,加入丹曲林钠20～25s后Ca2+浓度即开始下降,约50s后下降至最低值,然后稳定于低于原来基线的水平。结论丹曲林钠在高温诱导的海马神经细胞凋亡中具有重要的保护作用,在预防热致脑损伤疾病中具有一定的应用价值。     

关于肽类生长因子对神经发育作用及其机制的认识

肽类生长因子对神经系统发育发挥着重要的调控作用，与神经退行性疾病的发生和发展也密切相关，在研究过程中要运用哲学原理作指导，充分认识肽类生长因子结构和功能的多样性、其受体及其作用机制的复杂性，处理好基础研究与实践的辨证关系，从单纯分析研究走向系统研究。     

Neuroinflammation and astrocytic reaction in the course of Phoneutria nigriventer (armed-spider) blood–brain barrier (BBB) opening

Phoneutria nigriventer spider venom (PNV) causes uneven BBB permeability throughout different cerebral regions. Little is known about cellular and molecular responses which course with the PNV-induced BBB opening. We investigate by immunohistochemistry (IHC) and Western blotting (WB), the GFAP, S100, IFN-γ and TNF-α proteins expression in hippocampus and cerebellum after different time-points from venom or saline intravenous injection. All proteins variably altered its expression temporally and regionally. WB showed increased GFAP content at 15–45 min followed by a shift below the control level which was less pronounced in hippocampus. IHC showed reactive gliosis during all the trial period. In cerebellum, GFAP was mostly immunodetected in astrocytes of the molecular layer (Bergmann glia), as was S100 protein. The maximum S100 immunolabeling was achieved at 5 h. IFN-γ and TNF-α, expressed mostly by hippocampal neurons, increased along the trial period, suggesting a role in BBB permeability. In envenomed animals, closer contacts astrocyte–astrocyte, granule cells–granule cells and astrocytes-Purkinje cells were observed in cerebellum. Closer contacts between neurons–neurons–astrocytes–astrocytes were also seen in hippocampus. PNV contains serotonin, histamine, Ca²⁺ channels-blocking toxins, some of which affect glutamate release. The hypothesis that such substances plus the cytokines generated, could have a role in BBB permeability, and that calcium homeostasis loss and disturbance of glutamate release are associated with the marked GFAP/S100 reaction in Bergmann glia is discussed. The existence of a CNS mechanism of defense modulated differentially for fast synthesis and turnover of GFAP, S100, IFN-γ and TNF-α proteins was evident. A clear explanation for this differential modulation is unclear, but likely result from regional differences in astrocytic/neuronal populations, BBB tightness, and/or extent/distribution of microvasculature and/or ion channels density/distribution. Such differences would respond for transient characteristics of BBB disruption. This in vivo model is useful for studies on drug delivery throughout the CNS and experimental manipulation of the BBB.     

Glucose-supported oxidative metabolism and evoked potentials are sensitive to fluoroacetate, an inhibitor of glial tricar☐ylic acid cycle in the olfactory cortex slice

Optical absorbance change was measured by reflectance spectrophotometry in the olfactory cortex slice prepared from the rat brain. Optical absorbance of the piriform area of the slice was increased by perifusion with an anoxic (N₂-gassed) solution. Components of the absorbance spectrum recorded from the slice in anoxia corresponded to that of cytochromes (cyt)aa₃ and c + c₁, but did not to that of cyt c. Reduction of cytochromes in anoxia coincided with decrease in the amplitude of the presynaptic potential and a slower negative wave (N-wave). The reduced state of cytochromes switched to an oxidized state when a well-oxygenated solution was reintroduced. An almost complete recovery of redox state coincided with full recovery of the evoked potential. A metabolic inhibitor, 2-deoxy-d-glucose (2DG) (10 mM) or iodoacetic acid (IAA) (3 mM) caused little or slight oxidation of cytochromes, but significantly decreased the amplitude of evoked potentials. Marked oxidation of cytochromes was observed only by perifusion with a solution containing 2 DG (10 mM) and IAA (3 mM). The rate of oxygen uptake was significantly lowered by these metabolic inhibitors. When the slice was perifused with a solution containing fluoroacetate (1 or 10 mM), a selective inhibitor of glial metabolism, cytochromes shifted to oxidized levels. The amplitude of evoked potentials tended to decline by a low dose (1 mM), and significantly decreased by a high dose (10 mM) of fluoroacetate. Oxygen consumption of the slice was dose-relatedly lowered by fluoroacetate.These results indicate (1) that the mitochondrial redox state becomes reduced in anoxia and the evoked potential is concomitantly suppressed, (2) that metabolic and neuronal activities are primarily supported by glucose supply, and (3) that reducing equivalents into the respiratory chain are derived from metabolic activities, which are linked to glucose metabolism, in glia as well as in neurons of the olfactory cortex slice.     

强脑因子生物学特性的实验研究

目的 探讨强脑因子对大鼠胎鼠脑神经细胞培养物的生物学保护效应 方法 取16日龄Wistar大鼠脑神经细胞经体外培养后,分别进行(1)组织形态学观察:在神经细胞培养物中加入不同剂量强脑因子(1 10和100mg/L),光学显微镜下观察细胞形态学变化 在电子显微镜下观察神经细胞超微结构变比;(2)神经细胞代谢活性检测:应用四唑盐(tetrazolium,MTT)法测定不同剂量强脑因子对神经细胞代谢活性的影响;(3)可溶性蛋白质水平测定:应用Bradford蛋白定量法测定不同剂量强脑因子对神经细胞胞浆内可溶性蛋白质水平的影响;(4)强脑因子抗神经细胞凋亡试验:应用神经元特异性烯醇化酶(neuron-specific enolase,NSE)定量法,测定强脑因子与奥地利产脑活素对NSE活性表达的影响。结果(1)强脑因子可促进神经细胞分化成熟 突起增多并延长、细胞数量增加。(2)在不同剂量强脑因子作用下 神经细胞MTT代谢率增强,细胞浆内蛋白质水平升高 而且随着强脑因子剂量的增加均呈现出明显的剂量依赖关系;促进NSE表达活性,利于神经母细胞分化(3)强脑因子可增强神经细胞抗缺氧作用及抗谷氨酸所致的细胞凋亡效应 且功效强于奥地利产脑活素 结论 在相同实验条件下,强脑因子对体外培养的神经细胞有生物学保护作用,效果优于脑活素     

Insights on the pathophysiology of Alzheimer's disease: The crosstalk between amyloid pathology,neuroinflammation and the peripheral immune system

Alzheimer's disease (AD) is the most common form of dementia, whose prevalence is growing along with the increased life expectancy. Although the accumulation and deposition of amyloid beta (Aβ) peptides in the brain is viewed as one of the pathological hallmarks of AD and underlies, at least in part, brain cell dysfunction and behavior alterations, the etiology of this neurodegenerative disease is still poorly understood. Noticeably, increased amyloid load is accompanied by marked inflammatory alterations, both at the level of the brain parenchyma and at the barriers of the brain. However, it is debatable whether the neuroinflammation observed in aging and in AD, together with alterations in the peripheral immune system, are responsible for increased amyloidogenesis, decreased clearance of Aβ out of the brain and/or the marked deficits in memory and cognition manifested by AD patients. Herein, we scrutinize some important traits of the pathophysiology of aging and AD, focusing on the interplay between the amyloidogenic pathway, neuroinflammation and the peripheral immune system.     

JNK regulates FoxO-dependent autophagy in neurons

The cJun N-terminal kinase (JNK) signal transduction pathway is implicated in the regulation of neuronal function. JNK is encoded by three genes that play partially redundant roles. Here we report the creation of mice with targeted ablation of all three Jnk genes in neurons. Compound JNK-deficient neurons are dependent on autophagy for survival. This autophagic response is caused by FoxO-induced expression of Bnip3 that displaces the autophagic effector Beclin-1 from inactive Bcl-XL complexes. These data identify JNK as a potent negative regulator of FoxO-dependent autophagy in neurons.     

Reverse glial glutamate uptake triggers neuronal cell death through extrasynaptic NMDA receptor activation

Evidence have accumulated that reverse glutamate uptake plays a key role in the pathophysiology of cerebral ischemia. Here, we investigated the effects of glial glutamate transporter dysfunction on neuronal survival using the substrate inhibitor of glutamate transporters, l-trans-pyrrolidine,2-4,dicarboxylate (PDC), that partly mimics reverse glutamate uptake. On mice primary cortical co-cultures of neurons and astrocytes, PDC treatment triggered an elevation of extracellular glutamate concentration, induced neuronal calcium influx and a massive NMDA receptor (NMDAR) mediated-neuronal death without having any direct agonist activity on NMDARs. We investigated the NMDAR subpopulation activated by PDC-induced glutamate release. PDC application led to the activation of both subtypes of NMDARs but the presence of astrocytes was required to activate NMDARs located extra-synaptically. Extrasynaptic NMDAR activation was also confirmed by the loss of neuronal mitochondrial membrane potential and the inhibition of pro-survival p-ERK signalling pathway. These data suggest that reverse glial glutamate uptake may trigger neuronal death through preferential activation of extrasynaptic NMDAR-related pathways.     

Noggin蛋白对D 半乳糖致衰老小鼠学习记忆及海马齿状回神经发生的影响

目的观察侧脑室注射Noggin蛋白后对D 半乳糖致衰老模型小鼠学习记忆行为能力与海马齿状回神经发生的影响。方法采用皮下注射D 半乳糖构建衰老小鼠模型后,连续7?d侧脑室注射Noggin蛋白,对照组同时注射等量生理盐水,造模42?d后对各组小鼠进行Y迷宫学习记忆能力测试,用BrdU标记海马齿状回增殖细胞。 结果Y迷宫检测结果表明,模型组小鼠学习记忆能力较正常对照组明显降低（P<0.05）,而模型治疗组小鼠学习记忆能力较模型对照组明显改善（P<0.05）;模型组与模型对照组小鼠海马齿状回BrdU阳性细胞数较正常对照组减少（P<0.05）,而模型治疗组BrdU阳性细胞数较模型组、模型对照组显著增多（P<0.05）。结论侧脑室给予Noggin蛋白可改善衰老模型小鼠的空间学习及记忆能力,可能与Noggin能保护海马神经元并促使齿状回神经干细胞增殖有关。