大脑中动脉阻塞后脑组织病变过程及MDA含量变化

在大鼠中用热凝造成大脑中动脉阻塞而致脑局灶性缺血。电镜观察发现,在缺血2min后,神经细胞粗面内质网与线粒体即出现改变。光镜检查,缺氧10min后才出现神经细胞缺血改变;梗死灶周边微血管体积密度在缺血24h后即明显升高。肉眼检查,于缺血3h后可见梗死灶。在缺血2min后,脑组织内丙二醛(MOA)即升高,说明在缺血缺氧的早期,脂质过氧化作用加强。表明自由基在缺血性脑损伤早期即起重要作用。     

实验性高血压大鼠视网膜的光电镜观察

应用光、电镜方法观察12只正常大鼠视网膜,12只实验性高血压大鼠视网膜,结果表明:高血压大鼠视网膜毛细血管基膜增厚,管腔狭窄致视网膜缺血缺氧引起节细胞和视细胞外节的病变.多数节细胞水肿、胞浆淡染、线粒体空泡化、滑面内质网扩张、部份粗面内质网扩张、脱粒;甚至有少数节细胞胞膜破裂与邻近节细胞胞浆相融合.而视细胞的改变主要在于外节中膜盘凌乱,排列不整齐,特别是外节基底部新生的膜盘病变为甚.视网膜中的?细胞对缺氧抗力较强,未见明显病变.     

D-半乳糖衰老大鼠性腺轴系超微结构的变化

目的:观察D-半乳糖衰老大鼠性腺轴系超微结构的变化。方法:D-半乳糖连续腹腔注射制作亚急性衰老的大鼠模型,应用透射电镜观察模型大鼠下丘脑弓状核、垂体及睾丸超微结构的变化。结果:D-半乳糖衰老大鼠弓状核出现线粒体嵴断裂、粗面内质网脱颗粒、高尔基复合体扩张等变化;垂体促性腺激素细胞出现线粒体嵴断裂、粗面内质网扩张、高尔基复合体扩张等变化,并观察到脱粒细胞;睾丸支持细胞内溶酶体增多,内质网增生、扩张,线粒体嵴断裂,精原细胞可见胞质内出现许多空泡,并观察到了凋亡小体。结论:D-半乳糖衰老大鼠性腺轴系的超微结构发生了明显改变,揭示了D-半乳糖衰老过程中下丘脑垂体性腺轴的重要作用。     

家兔某种神经细胞的核膜皱折及其有关现象

用电子显微镜观察到,中枢神经系统中,特别是斜方体核中,某些神经细胞显示特有的核膜皱折。其中有一些是深的内析,也有一些只是沿着核边缘的浅陷。核膜内折腔中含有内质网和成堆浓颗粒,后者与胞浆中核糖核蛋白类似。在内折腔中有时看见体积较大的球形致密体,其中含有高电子密度的细粒,它们可能是溶酶体。内折中还有成组的大小不同球形空泡,其性质不明。凡核膜有深内折处,在其口部几乎总是具有线粒体的大量聚集。但是,在内折腔中的深部极少看见线粒体。核膜浅陷所形成的袋内常装有成堆的颗粒、粗面内质网和线粒体。成堆的核仁物质和一些核膜皱折(包括浅陷和深折)有互相接近的趋势。我们认为,某些神经细胞的核膜皱折代表一种动态变化,它在整个生命期中周期性地出现,这可能是与尼氏体的生物合成有关的一种生理过程。     

大鼠帕金森综合征模型脑的黑质、尾状核及中缝核的超微结构变化

目的　观察大鼠帕金森综合症模型脑的黑质、尾状核及中缝核神经元超微结构变化。方法　应用透射电镜。结果　上述核团神经元的超微结构均发生病理性改变 :神经细胞核膜皱缩 ,核膜凹凸不整 ,并有局部断裂 ;线粒体变性 ,基质浓度降低及空泡化 ;粗面内质网和高尔基复合体囊腔扩张变性 ;大量初级溶酶体及脂褐素集聚 ;出现了髓样体和多泡体等变性结构。结论　黑质、尾状核及中缝核神经元超微结构的病理性变化从而导致纹状体 黑质 纹状体锥体外路系环路功能障碍 ,是引发帕金森氏综合症的结构基础。     

小鼠乳腺腺癌细胞系MA782/5S-8102细胞的超微结构

对小鼠乳腺腺癌细胞系MA782/5 S-8102细胞的超微结构观察,可见细胞基质电子密度不同的亮细胞和暗细胞,细胞核呈明显畸形,核大,核仁数有所增加,核内异染色质浓聚,核膜肿胀,核质比例高。细胞质内核糖体、线粒体显著增加,粗面内质网明显扩张,高尔基体、溶酶体、脂质粒及微丝清楚可见,并观察到胞内A型病毒颗粒及从细胞表面微绒毛芽生的未成熟的B型样颗粒。细胞膜褶皱,细胞表面具有较丰富的微绒毛,在相邻细胞之间可观察到桥粒。结果表明MA782/5 S-8102细胞系细胞具有明显的恶性细胞特征。本文还对所出现的病毒进行了讨论。     

E_15胎鼠内侧膝状体超微结构观察

取E_(15).胎鼠内侧膝状体,固定、脱水、包埋、超薄切片,透射电镜观察.神经细胞散在分布,细胞核偏位,表面呈齿状,核膜下染色质较浓密.细胞浆含大量游离核糖体,粗面内质网已出现.线粒体嵴数目少,而其基质密度高.高尔基复合体的扁平囊可达5层之多.胞浆中可见中空的大泡.神经细胞的突起较少.本文认为E_(15)内侧膝状体处于巳分化、低发育状态.     

景垂片对小白鼠四氯化碳中毒后肝细胞的电镜观察

本文主要研究景垂片对小白鼠四氯化碳中毒后肝细胞超微结构的变化,实验结果如下:四氯化碳中毒后肝细胞的超微结构中以细胞核、线粒体、内质网及糖元等为主要变化。细胞核的核膜不规则呈锯齿状,染色质浓集成块状,甚至核溶介。线粒体广泛变性肿胀,嵴不清楚,有的嵴消失,基质透明甚至空泡化。粗面内质网呈囊状扩张,其膜上附着的核蛋白体脱落,滑面内质网也轻度扩张。其周围糖元明显减少。用景垂片治疗的小白鼠肝细胞接近正常,核圆形,核膜光滑,线粒体嵴清楚,细胞间可见清楚的桥粒结构,粗面内质网平行排列,膜上附着大量核蛋白体颗粒,滑面内质网分散于细胞质中,糖元颗粒丰富,所以景垂片对肝细胞有保护作用。     

实验性高血压大鼠视网膜的的光电镜观察

应用光、电镜方法观察１２只正常大鼠视网膜，１２只实验性高压大鼠视网膜，结果表明：高血压大鼠视网膜毛细血管基膜增厚，管腔狭窄致视网膜缺血缺氧引起节细胞和视细胞外节的病变。多数节细胞水肿、胞浆淡染、线粒体空泡化、滑面内质网扩张、部份粗面内质网扩张、脱粒；甚至有少数节细胞胞膜破裂与邻近节细胞胞浆相融合。而视细胞的改变主要在于外节中膜盘凌乱，排列不整齐，特别是外节基底部新生的膜盘病变为甚。视网膜中的Ｍｕｉ     

微丝抑制剂细胞松弛素D对ECa 109食管癌细胞的作用

经0.2～0.5微克/毫升细胞松弛素D处理后,ECa 109细胞以暗、亮细胞为主。在间期细胞中,出现了一种小细胞。其细胞间隙变大,微绒毛减少,出现了胞浆突。0.5～1微克/毫升细胞松弛素D处理后细胞表面出现芽胞,其中可含有内质网、高尔基复合器、线粒体等细胞器。在胞质中,可见到靶形线粒体、重膜夹片内质网与环形内质网;高尔基复合器分散。还出现一种多核巨细胞,一个细胞中可见2～6个核,核大小不一,形态各异,每个核的核膜变化很大,有些没有完整核膜。有丝分裂细胞仍可见到。根据细胞松弛素D所致ECa 109细胞超微结构的改变,提出了微丝在支持细胞结构与维持功能中的作用。并讨论了微丝与微管在维持细胞结构与功能的细胞骨架系统中作用的异同。     

实验性脑缺血后隔—视前区内神经元的病理组织学和超微结构变化

目的：为探讨急性脑缺血后出现性功能障碍的机理，方法：应用蒙古沙土鼠脑缺血再灌注模型，对脑隔－视前区内性功能调节相关神经元米镜和电镜下的病理组织学和超微结构改变进行了观察。结果：短时急性脑缺血再灌注造成的神经元密度和亚细胞水平的细胞变化是暂时的，可在２周内恢复。当脑缺血达１０分钟再灌注后神经元损害加重，且在２周后尚未恢复，损害主要为膜结构如线粒体、内质网等破坏。结论：神经元损伤程度与缺血时间及再灌注     

树鼩脑缺血时神经元线粒体渗透性转导孔开放对线粒体呼吸的影响

目的：揭示光化学诱导树鼩脑缺血后不同时间内，缺血神经元线粒体呼吸功能的变化，观察血小板活化因子（PAF）受体拮抗剂银杏内酯B（GB）和免疫抑制剂环孢菌素A （CsA）对线粒体呼吸及神经元线粒体渗透性转导孔（MPT）开放的影响，探讨二者可能的神经保护机制及缺血时MPT开放与线粒体呼吸的相互关系。方法：建立光化学诱导树鼩脑缺血模型，分离缺血后4、24、72 h大脑皮层线粒体，用氧电极极谱法测定线粒体呼吸。于缺血6 h分别注射GB和CsA，24 h时观察相关指标。另取分离的线粒体，用CaCl₂诱导MPT开放，再分别加入CsA或GB，观察其对线粒体肿胀的影响。结果：缺血脑皮层神经元线粒体Ⅲ态呼吸速度、呼吸控制率（RCR）及磷氧比（P/O）逐渐下降，以缺血24 h的变化为著，与假手术组相比均有显著差异（P<0.01）。给予GB或CsA，Ⅲ态呼吸速度显著大于对照组（P<0.01），P/O比上升（P<0.05）。CaCl₂可诱导MPT开放，线粒体肿胀而透光率迅速下降，CsA有效阻滞了MPT开放，GB则不然。结论：光化学诱导树鼩局灶脑缺血后，缺血皮层线粒体呼吸明显障碍，GB或CsA可不同程度地改善缺血神经元线粒体代谢，可能与GB拮抗神经细胞膜上PAF受体活化，间接调节线粒体呼吸有关；而CsA主要通过抑制MPT开放而改善线粒体呼吸而具有神经保护作用。     

Co-existence of necrosis and apoptosis in rat hippocampus following transient forebrain ischemia

Morphological changes of CA1 and CA3 pyramidal neurons in rat hippocampus at different intervals following transient forebrain ischemia were examined to determine the nature of post-ischemic cell death in these regions. In the CA1 region, swelling of small dendrites occurred at approximately 24 h reperfusion. At approximately 48 h reperfusion, swelling was found in large dendrites of many CA1 neurons and the mitochondria and endoplasmic reticulum (ER) were dilated. A small portion of neurons showed chromatin aggregation and nuclear indentation without swelling signs. At approximately 60 h reperfusion, swelling of somata was evident in many neurons. Large dense chromatin clumps with round or ovoid contour were found in other neurons. At 72 and 96 h after ischemia, many large vacuoles and glias with active phagocytosis were observed. At 7 days after ischemia, the tissue was compact and many glias were found in the region. Most of the CA3 neurons had normal appearance after ischemia. A total of 5-10% CA3 neurons exhibited shrinking nuclei and chromatin aggregation at approximately 24 h reperfusion. The number of these neurons decreased overtime and disappeared at 72 h after ischemia. These results demonstrate the co-existence of necrosis and apoptosis in the CA1 region after transient forebrain ischemia. Most CA3 neurons remained intact after ischemia while a small portion of them showed apoptotic cell death.     

Ultrastructural changes in the nephron during experimental ischemia and postmortem survival

Ultrastructural analysis showed differences in the response of the epithelium of the proximal and distal portions of the nephron during postmortem survival of the kidney and its experimental ischemia in noninbred albino rats. During autolysis of the organ in the cadaver intracellular edema develops in the tubular epithelium and characteristic changes appear in the ultrastructure of the mitochondria. Under the conditions of experimental ischemia, marked changes in the lysosomal system of the cells, swelling of the mitochondria, and considerable dilatation of the cisterns of the endoplasmic reticulum and the Golgi lamellar complex take place against the background of intracellular edema.Labortory of Electron Microscopy, Central Research Laboratory, N. I. Pirogov Second Moscow Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR Yu. M. Lopukhin.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 79, No. 3, pp. 118–121, March, 1975.     

应用激光共聚焦扫描显微镜测定缺氧对大鼠脑微血管内皮细胞Ca2＋含量的影响

应用Ｕｌｔｉｍａ型激光共聚焦扫描显微镜、ｆｌｕｏ－３荧光探针，检测大鼠脑微血管内皮细胞在正常体外培养及缺氧培养时游离钙含量的动态变化。缺氧由培养液中加入２ｍｍｏｌ连二亚硫酸钠（Ｎａ２Ｓ２Ｏ４）同时充入Ｎ２（９５％）、ＣＯ２（５％）气体造成。实验结果发现，当缺氧１～２ｍｉｎ时，内皮细胞Ｃａ２＋含量迅速增加，２～３ｍｉｎ达高峰。此后，尽管内皮细胞仍处于缺氧条件，荧光强度却逐渐减弱。停止缺氧后，荧光强度曲线可趋于稳定。应用Ｎｉｋｏｎ倒置相差显微镜观察内皮细胞形态学变化，发现缺氧３～５ｍｉｎ，内皮细胞发生肿胀。缺氧８～１０ｍｉｎ，细胞表面有明显受损迹象。推测其形态学的变化与胞内Ｃａ２＋含量的增高有关     

Progression from ischemic injury to infarct following middle cerebral artery occlusion in the rat.

Focal brain ischemia induced in rats by occlusion of an intracranial artery is a widely used paradigm of human brain infarct. Details of the structural changes that develop in either the human or the rat brain at various times after occlusion of an intracranial artery are incompletely characterized. We studied, in 48 adult Wistar rats, structural alterations involving the cerebral hemisphere ipsilateral to an arterial occlusion, at intervals ranging from 30 min to 7 days. Microscopic changes developed over time in separate areas of the corresponding cerebral hemisphere in a predictable pattern, appearing as small lesions in the preoptic area (30 minutes), enlarging to involve the striatum, and finally involving the cerebral cortex. Two types of neuronal responses were noted according to the time elapsed; acute changes (up to 6 hours) included scalloping, shrinkage, and swelling, whereas delayed changes (eosinophilia and karyolysis) appeared later (> or = 12 hours). Three types of astrocytic responses were noted. 1) Cytoplasmic disintegration occurred in the preoptic area at a time and in a place where neurons appeared minimally injured. 2) Nuclear and cytoplasmic swelling were prominent responses in the caudoputamen and cerebral cortex at a time when neurons showed minimal alterations. 3) Increased astrocytic glial fibrillary acidic protein reactivity was noted at the interface between the lesion and the surrounding brain tissue after 4 to 6 hours. The gross pattern of the brain lesion and the maturation of neuronal changes typical of a brain infarct have a predictable progression. Focal brain ischemia of up to 6-hour duration does not induce coagulation necrosis.     

Effects of anoxia and aglycemia on cytosolic calcium regulation in rat sensory neurons

Nociceptive neurons play an important role in ischemia by sensing and transmitting information to the CNS and by secreting peptides and nitric oxide, which can have local effects. While these responses are probably primarily mediated by acid sensing channels, other events occurring in ischemia may also influence neuron function. In this study, we have investigated the effects of anoxia and anoxic aglycemia on Ca2+ regulation in sensory neurons from rat dorsal root ganglia. Anoxia increased [Ca2+]i by evoking Ca2+ release from two distinct internal stores one sensitive to carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone (FCCP) and one sensitive to caffeine, cyclopiazonic acid (CPA), and ryanodine [assumed to be the endoplasmic reticulum (ER)]. Anoxia also promoted progressive decline in ER Ca2+ content. Despite partially depolarizing mitochondria, anoxia had relatively little effect on mitochondrial Ca2+ uptake when neurons were depolarized but substantially delayed mitochondrial Ca2+ release and subsequent Ca2+ clearance from the cytosol on repolarization. Anoxia also reduced both sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) activity and Ca2+ extrusion [probably via plasma membrane Ca2+-ATPase (PMCA)]. Thus anoxia has multiple effects on [Ca2+]i homeostasis in sensory neurons involving internal stores, mitochondrial buffering, and Ca2+ pumps. Under conditions of anoxic aglycemia, there was a biphasic and more profound elevation of [Ca2+]i, which was associated with complete ER Ca2+ store emptying and progressive, and eventually complete, inhibition of Ca2+ clearance by PMCA and SERCA. These data clearly show that loss of oxygen, and exhaustion of glycolytic substrates, can profoundly affect many aspects of cell Ca2+ regulation, and this may play an important role in modulating neuronal responses to ischemia.     

Morphological changes of c-Fos-like immunoreactivity in rat cerebral cortex after cerebral ischemia and reperfusion with special reference to vasoactive intestinal polypeptide

We investigated morphological changes in neurons with c-Fos-like immunoreactivity (c-Fos-LI) after cerebral ischemia by light and electron microscopic immunocytochemistry. Strong c-Fos-LI was observed in layers II–VI of the cerebral cortex with an especially abundant distribution in the nuclei of layers II, IV, and VI ipsilateral to the lesioned side. Reperfusion after ischemia had a greater effect on the expression of c-Fos-LI than did permanent ischemia. Vasoactive intestinal peptide (VIP)-positive neurons were seen scattered in layers II–V of the cerebral cortex. Some VIP-positive neurons showed c-Fos-LI after ischemia. Electron microscopy revealed c-Fos-LI in euchromatin in the nuclei of c-Fos-positive cells. Dilatation of the cisternae of the rough endoplasmic reticulum and the presence of numerous secondary lysosomes were found in neurons on the lesioned side after 12h of reperfusion. Some VIP-containing neurons revealed c-Fos-LI with reperfusion after ischemia by a double immunostaining method on the same tissue section. These findings suggest that ischemia potentiates c-fos expression in VIP- or other transmitter- or modulator-containing neurons, thereby protecting from neuronal cell death.     

Benzodiazepines protect hippocampal neurons from degeneration after transient cerebral ischemia: an ultrastructural study

The ability of full and partial benzodiazepine receptor agonists to prevent DNA fragmentation and neuronal death after transient cerebral ischemia was investigated in the Mongolian gerbil. Diazepam (10mg/kg, i.p.) or the partial agonist imidazenil (3mg/kg, i.p.) was administered 30 and 90min after transient forebrain ischemia produced by occlusion of the carotid arteries for 5min. Treatment with diazepam completely protected CA1b hippocampal pyramidal neurons in 94% of the animals and partially protected pyramidal neurons in 6% of the animals, as assessed with a standard Nissl stain three and four days after ischemia. DNA fragmentation was examined by the terminal dUTP nick-end labeling (TUNEL) reaction. Prior to cell death, there were no TUNEL-positive neurons in area CA1b. By three days after ischemia, when neuronal degeneration was nearly complete, 14 out of 16 gerbils exhibited a positive TUNEL reaction throughout area CA1b stratum pyramidale. In 13 out of 14 gerbils treated with diazepam, no TUNEL-positive neurons were observed in this region. Imidazenil was less effective than diazepam with respect to both neuroprotection and prevention of DNA fragmentation. Three days after ischemia, six out of eight gerbils treated with imidazenil showed partial to complete neuroprotection. Imidazenil completely prevented DNA fragmentation in only one of the animals; varying degrees of TUNEL reaction persisted in the remainder. To determine whether the neurons protected by diazepam had a normal ultrastructure, gerbils were killed two to 30 days after ischemia and the hippocampal neurons in area CA1b were examined by electron microscopy. Within the first 48h after ischemia, early cytoplasmic changes of varying degrees (e.g., vacuolation, rough endoplasmic reticulum stacking, swollen mitochondria) and electron-dense dendrites were observed in gerbils not treated with diazepam. Degeneration was nearly complete by three days after ischemia. In contrast, pyramidal neuron ultrastructure appeared normal in gerbils that exhibited complete area CA1b neuroprotection (defined at the light microscope level) by diazepam when studied two, seven or 30 days after ischemia. In gerbils with partial protection of area CA1b, most of the remaining neurons exhibited varying degrees of necrosis when studied 30 days after ischemia. No apoptotic bodies were observed.We conclude that: (i) diazepam can fully protect CA1 pyramidal cells from the toxic effects of transient cerebral ischemia; (ii) when diazepam affords only partial neuroprotection, the residual CA1 pyramidal cells exhibit ultrastructural abnormalities consistent with necrotic damage; and (iii) diazepam is a more efficacious neuroprotectant than the partial benzodiazepine receptor agonist, imidazenil.     

Interference of levamisole with cerbral edema

The anthelmintic acnd immunomodulator drug levamisole is also a thromboxane synthetase inhibitor. The effect of levamisole on cerebral edema in Mongolian gerbils and in rat models of stroke was evaluated. Cerebral ischemia was produced in gerbils by right carotid ligation and in rats by right carotid ligation and anoxia. Mortality and right hemisphere edema were evaluated 24 hours after induction of cerebral anoxia in levamisole treated animals. Levamisole failed to protect gerbils from death or cerebral edema but decreased dose-dependently the cerebral edema in rats. The fact that levamisole inhibits thromboxane synthetase and decrease cerebral swelling in rats supportes further tests against human stroke.