大鼠视神经切断后视网膜外网层突触可塑性研究

应用闪光视网膜电图(fERG)、细胞色素c氧化酶(CO)组织化学染色及突触囊泡素免疫荧光染色方法检测视神经切断术后,视网膜外网层相关神经元的功能活动及突触可塑性变化。结果显示:fERGb波峰潜伏期在视神经损伤后均显著延长;b波振幅在损伤第3、5d组增高,此后逐渐下降并在7、14、21d组低于正常。外网层CO活性在视神经切断第3、5d上调,此后逐渐下降,至第14、21d低于正常。外网层突触囊泡素阳性颗粒在视神经切断第5d增多,此后逐渐下降,至第14、21d低于正常。本研究结果提示视神经切断后,视网膜内外网层神经元的功能在早期将出现一过性的增强,结构也有相应的代偿性改变,随后即发生跨神经元的逆行性溃变。     

Angiomatoid (malignant) fibrous histiocytoma: a peculiar low-grade tumor showing immunophenotypic heterogeneity and ultrastructural variations

To clarify the cellular differentiation features and facilitate diagnosis of angiomatoid (malignant) fibrous histiocytoma (AFH), four cases of AFH were examined by clinicopathologic, immunohistochemical and ultrastructural analyses. The age of the patients ranged from 10 to 24 years (mean, 17 years) and the sex distribution was equal. All cases were of subcutaneous origin: three arose in the trunk and one in the upper extremity. All patients presented with systemic symptoms, including inflammatory signs and anemia. After a mean follow up of 11 years 3 months, all patients were alive and well, although one patient twice developed local recurrence after surgery. All cases presented as multinodular, cystic and hemorrhagic tumors ranging in size from 4 to 11 cm (mean, 8 cm) and were characterized by sheets of bland spindle or round cells with oval nuclei within a circumscribed nodule often surrounded by a lymphocytic cuff. One tumor showed predominantly round cell morphology similar to Ewing's sarcoma/primitive neuroectodermal tumor. All cases (100%) exhibited immunoreactivity for vimentin, desmin, CD68 and CD57 (Leu-7). Three cases (75%) were positive for synaptophysin, and reactivity for alpha-smooth muscle actin, epithelial membrane antigen, neuron-specific enolase and CD99 (O-13) was present in two cases (50%) each. The three cases examined by electron microscopy had a mixture of fibrohistiocytic, myofibroblastic and undifferentiated cells containing cytoplasmic processes and dense-core granules. It is important for accurate diagnosis of this peculiar soft-tissue tumor to recognize that it has a variety of immunophenotypes, such as histiocytic, myofibroblastic, epithelial and neural, and may occasionally have a predominantly round cell morphology.     

丙烯酰胺对仔鼠大脑额叶皮质神经元DCX和SYN表达的影响

目的:探究丙烯酰胺(acrylamide,ACR)暴露对仔鼠大脑额叶皮质神经元发育的影响。方法:孕鼠随机分为4组,自怀孕第6 d起对照组和实验组分别给予蒸馏水和(50,100,200)μg/ml ACR饮水,直至仔鼠出生21 d。免疫组织化学法观察仔鼠额叶皮质神经元微管相关蛋白(doublecortin,DCX)和突触素(synaptophysin,SYN)的表达情况。结果:ACR实验组和对照组额叶皮质神经元均有DCX和SYN的表达。DCX和SYN免疫阳性产物均为棕黄色颗粒状,表达于胞浆内。与对照组相比,ACR染毒高剂量组(200μg/ml)DCX表达显著减少(P0.05),而低、中剂量组(50μg/ml和100μg/ml)的减少不明显,无统计学意义(P0.05);与对照组相比,ACR实验组SYN的表达显著降低,呈剂量依赖性,且组间差异明显(P0.05)。结论:ACR染毒可能是通过降低DCX和SYN的表达,干扰神经元的迁移分化和突触的形成,从而影响额叶皮质的发育。     

Neurotransmitter diversity in pre‐synaptic terminals located in the parvicellular neuroendocrine paraventricular nucleus of the rat and mouse hypothalamus

Virtually all rodent neuroendocrine corticotropin‐releasing‐hormone (CRH) neurons are in the dorsal medial parvicellular (mpd) part of the paraventricular nucleus of the hypothalamus (PVH). They form the final common pathway for adrenocortical stress responses. Their activity is controlled by sets of GABA‐, glutamate‐, and catecholamine‐containing inputs arranged in an interactive pre‐motor network. Defining the nature and arrangement of these inputs can help clarify how stressor type and intensity information is conveyed to neuroendocrine neurons. Here we use immunohistochemistry with high‐resolution 3‐dimensional image analyses to examine the arrangement of single‐ and co‐occurring GABA, glutamate, and catecholamine markers in synaptophysin‐defined pre‐synaptic terminals in the PVHmpd of unstressed rats and Crh‐IRES‐Cre;Ai14 transgenic mice: respectively, vesicular glutamate transporter 2 (VGluT2), vesicular GABA transporter (VGAT), dopamine β‐hydroxylase (DBH), and phenylethanolamine n ‐methyltransferase (PNMT). Just over half of all PVHmpd pre‐synaptic terminals contain VGAT, with slightly less containing VGluT2. The vast majority of terminal appositions with mouse CRH neurons occur non‐somatically. However, there are significantly more somatic VGAT than VGluT2 appositions. In the rat PVHmpd, about five times as many pre‐synaptic terminals contain PNMT than DBH only. However, because epinephrine release has never been detected in the PVH, PNMT terminals may functionally be noradrenergic not adrenergic. PNMT and VGluT2 co‐occur in some pre‐synaptic terminals indicating the potential for co‐transmission of glutamate and norepinephrine. Collectively, these results provide a structural basis for how GABA/glutamate/catecholamine interactions enable adrenocortical responses to fast‐onset interosensory stimuli, and more broadly, how combinations of PVH neurotransmitters and neuromodulators interact dynamically to control adrenocortical activity.     

Morphofunctional characteristics of the lumbar enlargement of the spinal cord in rats

The topography of the lumbar enlargement of the spinal cord in rats was studied; an immunohistochemical method was used to determine the distribution of synaptophysin — a membrane protein of synaptic vesicles. Synaptophysin-immunoreactive structures were detected in the gray matter of all Rexed laminae, around most neurons and in the neuropil. Previously undescribed subpial synaptic contacts were detected immunohistochemically in the white matter and confirmed by electron microscopy. A non-myelinated component of the corticospinal tract, including axonal varicosities and synaptic contacts, was observed in the dorsal part of the white matter of the lumbar enlargement of the spinal cord. __________ Translated from Morfologiya, Vol. 132, No. 5, pp. 33–37, September–October, 2007.     

痴呆模型鼠海马突触素改变及其与学习记忆的关系

探讨痴呆模型鼠海马的突触素改变及其与学习记忆的关系。切断成年SD大鼠左侧穹窿海马伞(Fimbria-Fomix,FF),建立隔海马胆碱能系统损害的痴呆模型。损伤4周后,用Y型迷宫检测大鼠学习记忆能力,免疫组织化学染色和图象分析技术等方法对大鼠海马突触素进行定量分析。结果表明,损伤组学习记忆能力(3.82±0.64)明显低于正常组(8.81±0.32)(P<0.01);与正常组相比,损伤组损伤侧海马CA1区多形层、辐射层、腔隙分子层和齿状回分子层突触素免疫反应物的光密度明显降低,其光密度值分别是43.40±2.57;40.2l±3.22;12.37±1.87;26.63±2.36(P<0.01),并与其学习记忆能力呈显著正相关。本研究结果提示,痴呆模型鼠海马突触素与学习记忆的关系密切。     

大鼠海马CA3区在学习记忆时突触可塑性的变化

目的：探讨学习记忆的形成和遗忘与突触可塑性的关系。方法：用水迷宫训练大鼠21天建立空间辨别性学习记忆模型,随后停止训练,时间分别为3天,7天及14天,用免疫组化方法和图像分析技术,检测了突触素在大鼠海马CA3区表达的变化。结果：对照组大鼠海马CA3区突触素的表达弱,免疫反应产物呈点状颗粒,沿辐射层长轴分布,多形层也有散在分布;模型组大鼠突触素染色明显比对照组的深,密集的小颗粒呈带状沿辐射层排列,在辐射层的底部可见一些大的阳性颗粒,随着停止训练时间的延长,突触素的表达逐渐减弱。结论：空间学习记忆导致海马CA3区辐射层新突触的形成,而随着空间学习记忆的遗忘,又致新形成突触的消退。     

电针结合重复经颅磁刺激对脑缺血大鼠海马突触素的影响

目的：研究电针结合重复经颅磁刺激对脑缺血大鼠海马突触素的影响。方法：120只Wistar大鼠随机分为正常组、模型组、电针组、重复经颅磁刺激组和电针结合重复经颅磁刺激组, 根据不同时间点每个组又细分为7d、14d和28d组3个亚组。复制大脑中动脉栓塞模型,分别给予电针、磁刺激和电针结合磁刺激干预。免疫荧光标记方法观察缺血侧海马CA3区突触素的表达,蛋白印迹技术定量分析不同时间点、不同组别之间缺血侧海马突触素表达的差异。结果：电针、磁刺激和电针结合磁刺激都能显著上调3个时间点海马突触素的表达。从时间上看,随着治疗时间的增加,突触素的表达逐步上调;不同组间比较,第28天时电针结合磁刺激海马突触素的表达最显著。结论：三种干预方法都能促进脑缺血大鼠海马突触素的表达,其中第28天时电针结合磁刺激效果最显著。     

康复训练对大脑中动脉闭塞大鼠脑梗死灶周围突触素表达的影响

目的:研究康复训练对大鼠脑梗死灶周围突触素(P38)表达的影响。方法:40只Wistar大鼠采用Longa颈外动脉线栓法制备大鼠大脑中动脉闭塞模型,将模型大鼠随机分为康复组、造模对照组,康复组每天进行1小时滚筒、平衡木、转棒及网屏训练,造模对照组置于普通笼中饲养,不予以康复训练。每组随机分为3天、7天、14天、21天4个时间点,每个时间点各5只大鼠,分别于相应天数取脑,采用免疫组织化学方法观察每个时间点脑梗死灶周围突触素的表达。结果:康复组神经功能评分较造模对照组为好(P<0.05);突触素阳性细胞于脑缺血3天后即已出现,7天、14天、21天大量表达,7天为高峰,且康复组较造模对照组多(P<0.05)。随时间延长免疫组化染色变深。结论:康复训练能促进中枢神经系统表达较高水平的突触素。     

骨髓单核细胞移植对脊髓横断大鼠神经营养因子-3和突触素表达的影响

目的:探讨骨髓单核细胞(BMMNCs)移植对脊髓横断(SCT)大鼠脊髓组织中神经营养因子-3(NT-3)和突触素(SYN)表达的影响。方法:146只Winstar大鼠(SPF级,雌雄不限)随机分为3组:SCT组49只,建立SCT模型;实验组49只,建立SCT模型,给予BMMNCs移植治疗;假手术组48只,切除对应的椎板不损伤脊髓;各组大鼠分别于术后5、7、14和21d行后肢功能BBB评分,RT-PCR和免疫组织化学技术检测受损脊髓组织中NT-3和SYN的表达。结果:术后5、7、14和21d各时间点各组大鼠后肢BBB评分比较,SCT组和实验组均低于假手术组(P0.05),且SCT组更低于实验组(P0.05)。术后5、7、14和21d各时间点NT-3阳性细胞数及NT-3mRNA比较,SCT组和实验组均高于假手术组(P0.05),且SCT组更低于实验组(P0.05)。SYN阳性颗粒数及SYN mRNA比较,SCT组和实验组均低于假手术组(P0.05),且SCT组更低于实验组(P0.05)。结论:BMMNCs能够上调局部损伤脊髓NT-3和SYN的表达。