兔颈上神经节神经元的急性分离及其通道电流记录

目的 探讨兔颈上神经节神经元分离及电生理研究的方法.方法 为了获得适用于膜片钳实验技术的单个颈上神经节神经细胞,应用酶和机械分离相结合的方法,急性分离20～30 d幼兔的单个颈上神经节神经元.通过倒置显微镜直接观察以及全细胞膜片钳技术的电压钳和电流钳分别对分离得到的颈上神经节神经元的形态学和电生理学特性进行研究.结果 急性分离所得活性较好的颈上神经节神经元胞体具有圆形和顶树突特征,立体感强,光晕明显.在全细胞膜片钳记录模式下可记录到全细胞电流、钠电流、钾电流及动作电位.结论 该方法可以得到形态和生理特性良好的单个颈上神经节神经元;该方法适用于膜片钳技术的研究,对深入探讨药物、物理因子等对神经节神经元离子通道的影响具有重要的应用价值.     

触液核在大鼠慢性瘙痒维持中的作用

目的 探讨触液核在大鼠慢性瘙痒维持中的作用.方法 雄性SD大鼠,3月龄,体重240～ 280 g.第一部分采用随机数字表法,将42只大鼠分为3组(n=14):生理盐水组(C组)、丙酮组(A组)和恶唑酮组(O组).O组于颈背部涂抹0.5％恶唑酮15μl,C组和A组分别涂抹等容量生理盐水和丙酮,分别于给药后7、9、13、16、17、18、21、23 d重复上述处理,记录每次给药后30 min内搔抓次数,每组取6只动物,在最后1次涂抹恶唑酮后2h取脑组织,测定触液核c-Fos表达.第二部分 采用随机数字表法,将24只大鼠分为3组(n=8):正常对照组(C1组)、慢性瘙痒组(CI组)和慢性瘙痒+触液核毁损术组(CI+ KA组),CI组和CI+ KA组采用上述方法制备慢性瘙痒模型,触液核毁损术于第8次给药后6h实施,并记录第9次给药后30 min内搔抓次数.结果 第一部分 与C组比较,A组T4-8时搔抓次数增多,O组T1-8时搔抓次数增多,A组和O组触液核c-Fos表达上调(P＜0.05);与A组比较,O组T1-8时搔抓次数增多,触液核c-Fos表达上调(P＜0.05).第二部分 与C1组比较,CI组和CI+ KA组搔抓次数增多(P＜0.05),而CI+ KA组搔抓次数少于CI组(P＜0.05).结论 触液核参与了大鼠慢性瘙痒的维持.     

高脂饮食对孕鼠子痫前期样改变及神经元mGluR1影响研究

目的探讨高脂饮食对孕鼠子痫前期样改变及神经元m GluR1的影响。方法将40只雌性大鼠随机分为非孕对照组(NN组)、妊娠对照组(PN组)、非孕高脂饮食组(NF组)及妊娠高脂饮食组(PF组),每组各10只。测量4组雌性大鼠收缩压、尿蛋白及血清生化指标;RT-PCR、Western Blot检测代谢型谷氨酸受体(m GluR1)mRNA及蛋白表达。结果孕鼠妊娠第16、20天,PF组收缩压明显高于NN组、PN组、NF组(P<0.05)。孕鼠妊娠第15、19天,PF组24 h尿蛋白含量明显高于NN组、PN组、NF组(P<0.05)。NF组TG、LDL-C、FFA、Lp-PLA2、LDL-C/HDL-C明显高于NN组,HDL-C明显低于NN组(P<0.05)。PF组TG、LDL-C、FFA、Lp-PLA2、LDL-C/HDL-C明显高于PN组,HDL-C明显低于PN组(P<0.05)。PF组TG、LDL-C、FFA、Lp-PLA2、HDL-C明显高于NF组(P<0.05)。RT-PCR及Western blot检测显示,PF组m GluR1 mRNA及蛋白表达明显增强,高于NN组、PN组、NF组(P<0.05)。结论高脂饮食可诱发孕鼠子痫前期样改变,m GluR1 mRNA及蛋白表达上调可促进子痫发生。     

Potential neuroprotective role of astroglial exosomes against smoking-induced oxidative stress and HIV-1 replication in the central nervous system

Introduction: HIV-1-infected smokers are at risk of oxidative damage to neuronal cells in the central nervous system by both HIV-1 and cigarette smoke. Since neurons have a weak antioxidant defense system, they mostly depend on glial cells, particularly astrocytes, for protection against oxidative damage and neurotoxicity. Astrocytes augment the neuronal antioxidant system by supplying cysteine-containing products for glutathione synthesis, antioxidant enzymes such as SOD and catalase, glucose for antioxidant regeneration via the pentose-phosphate pathway, and by recycling of ascorbic acid.

Areas covered: The transport of antioxidants and energy substrates from astrocytes to neurons could possibly occur via extracellular nanovesicles called exosomes. This review highlights the neuroprotective potential of exosomes derived from astrocytes against smoking-induced oxidative stress, HIV-1 replication, and subsequent neurotoxicity observed in HIV-1-positive smokers.

Expert opinion: During stress conditions, the antioxidants released from astrocytes either via extracellular fluid or exosomes to neurons may not be sufficient to provide neuroprotection. Therefore, we put forward a novel strategy to combat oxidative stress in the central nervous system, using synthetically developed exosomes loaded with antioxidants such as glutathione and the anti-aging protein Klotho.     

In vivo assessment of guided neural stem cell differentiation in growth factor immobilized chitosan-based hydrogel scaffolds

In this study, we demonstrate that a unique growth factor-biomaterial system can offer spatial control of growth factors with sustained signaling to guide the specific lineage commitment of neural stem/progenitor cells (NSPCs) in vivo. First, recombinant fusion proteins incorporating an N-terminal biotin tag and interferon-γ (IFN-γ), platelet derived growth factor-AA (PDGF-AA), or bone morphogenic protein-2 (BMP-2) were immobilized to a methacrylamide chitosan (MAC) based biopolymer via a streptavidin linker to specify NSPC differentiation into neurons, oligodendrocytes, or astrocytes, respectively. MAC was mixed with growth factors (immobilized or adsorbed), acrylated laminin, NSPCs, and crosslinked within chitosan conduits. This system mimics regenerative aspects of the central nervous system ECM, which is largely composed of a crosslinked polysaccharide matrix with cell-adhesive regions, and adds the new functionality of protein sequestration. We demonstrated that these growth factors are maintained at functionally significant levels for 28 d in vitro. In the main study, immobilized treatments were compared to absorbed and control treatments after 28 d in vivo (rat subcutaneous). Masson's Trichrome staining revealed that small collagen capsules formed around the chitosan conduits with an average acceptable thickness of 153.07 ± 6.02 μm for all groups. ED-1 staining showed mild macrophage clustering around the outside of chitosan conduits in all treatments with no macrophage invasion into hydrogel portions. Importantly, NSPC differentiation staining demonstrated that immobilized growth factors induced the majority of cells to differentiate into the desired cell types as compared with adsorbed growth factor treatments and controls by day 28. Interestingly, immobilized IFN-γ resulted in neural rosette-like arrangements and even structures resembling neural tubes, suggesting this treatment can lead to guided dedifferentiation and subsequent neurulation.     

自噬及其抑制剂对脑损伤后脑细胞的作用

自噬是溶酶体清除并利用降解产物的过程,有助于保持蛋白代谢平衡及维持细胞环境的稳定,广泛参与多种病理生理过程.虽然近年在自噬的调控和分子机制等方面取得了一些进展,但是对细胞自噬与神经系统疾病的研究才刚刚开始.有研究发现,当癫(癎)发作时,将自噬抑制剂注入大鼠体内,可使抽搐的程度降低.故提出自噬可能与脑损伤及其信号转导有关,自噬通过某些信号通路加重脑损伤的假说.该文概述自噬及其抑制剂的新进展并进一步探讨对神经系统的作用.     

针刺治疗PTSD神经生物学研究进展

近年来,随着经济社会的快速发展与社会关系的复杂化和多元化,诸如自然灾害、暴力犯罪、性侵害等创伤性事件频频发生,创伤后应激障碍（PTSD）的关注度正在逐年上升,如何防治PTSD成为重要的研究课题。针灸作为我国传统医学的瑰宝,在精神疾病的预防和治疗方面有着丰富的经验和独特的优势,临床研究证实,针刺能有效改善PTSD的相关症状,然而其神经生物学机制到底为何,至今仍无定论。基于此,本文综述了近些年发表的相关研究,企图初步揭示针刺治疗PTSD内在的神经生物学机制,为临床治疗提供参考。     

大鼠腰骶髓和延髓星形胶质细胞及神经元对慢性结肠炎的反应

目的探讨大鼠腰骶髓和延髓星形胶质细胞及神经元对慢性结肠炎的反应,及反应性星形胶质细胞和反应性神经元之间的关系.方法成年雄性SD大鼠,实验组（n=17）给予三硝基苯磺酸（TNBS）灌肠诱导结肠炎;对照组（n=16）给予生理盐水灌肠.免疫组织化学法显示大鼠腰骶髓和延髓内胶质原纤维酸性蛋白（GFAP）阳性星形胶质细胞和Fos阳性神经元.结果TNBS灌肠后,GFAP阳性星形胶质细胞主要分布在脊髓背角浅层（Ⅰ～Ⅱ层）、中间外侧核（Ⅴ层）、后连合核（Ⅹ层）和腹角外侧核（Ⅸ层）.Fos阳性神经元集中分布在背角深层（Ⅲ～Ⅳ,Ⅴ～Ⅵ层）.在延髓,两者均主要分布在由孤束核、中间网状带和腹外侧区组成的延髓内脏带（MVZ）.TNBS灌肠后3、7、14 d,脊髓中GFAP阳性细胞密度明显高于对照组（P＜0.05）.TNBS灌肠后3 d,延髓中GFAP阳性细胞密度明显高于对照组（P＜0.05）.TNBS灌肠后28 d,脊髓和延髓中GFAP阳性细胞密度下降,与对照组无显著性差异（P＞0.05）.结论结肠炎性刺激引起脊髓和延髓中星形胶质细胞激活.随着结肠炎的恢复,星形胶质细胞的反应性下降.在延髓内脏带,反应性星形胶质细胞与反应性神经元关系密切.     

Dil散射标记神经元及神经胶质细胞技术介绍

目的对标记神经元和神经胶质的DiI散射法（DiI diolistic assay）进行改进,使操作更简捷,效果更为理想。方法用C57／B6J小鼠,对固定或培养的脑片内神经元与神经胶质细胞进行DiI散射法标记。结果该方法可以显示中枢神经系统内神经元及神经胶质细胞的细微结构,其中包括树突小棘。结论DiI散射标记法标记细胞的细微结构效果得到改善,可用于对树突棘分析,特别是可以直接在培养的脑片上对神经元与神经胶质进行活体标记。     

Graphene oxide-induced neurotoxicity on neurotransmitters,AFD neurons and locomotive behavior in Caenorhabditis elegans

Graphene oxide (GO) and graphene-based nanomaterials have been widely applied in recent years, but their potential health risk and neurotoxic potentials remain poorly understood. In this study, neurotoxic potential of GO and its underlying molecular and cellular mechanism were investigated using the nematode, Caenorhabditis elegans. Deposition of GO in the head region and increased reactive oxygen species (ROS) was observed in C. elegans after exposure to GO. The neurotoxic potential of GO was then investigated, focusing on neurotransmitters contents and neuronal activity using AFD sensory neurons. The contents of all neurotransmitters, such as, tyrosine, tryptophan, dopamine, tyramine, and GABA, decreased significantly by GO exposure. Decreased fluorescence of Pgcy-8:GFP, a marker of AFD sensory neuron, by GO exposure suggested GO could cause neuronal damage on AFD neuron. GO exposure led decreased expression of ttx-1 and ceh-14, genes required for the function of AFD neurons also confirmed possible detrimental effect of GO to AFD neuron. To understand physiological meaning of AFD neuronal damage by GO exposure, locomotive behavior was then investigated in wild-type as well as in loss-of-function mutants of ttx-1 and ceh-14. GO exposure significantly altered locomotor behavior markers, such as, speed, acceleration, stop time, etc., in wild-type C. elegans, which were mostly rescued in AFD neuron mutants. The present study suggested the GO possesses neurotoxic potential, especially on neurotransmitters and AFD neuron in C. elegans. These findings provide useful information to understand the neurotoxic potential of GO and other graphene-based nanomaterials, which will guide their safe application.