转染正义血管内皮细胞生长因子cDNA对大鼠肺泡巨噬细胞趋化蛋白1表达的影响

目的探讨博莱霉素(BLM)致大鼠肺微血管内皮细胞紧密连接变化特征以及血管内皮细胞生长因子(VEGF)对肺微血管内细胞中巨噬细胞趋化蛋白1(MCP-1)mRNA表达的影响。方法健康SD大鼠按随机数字表法随机分为对照组和实验组。实验组大鼠制作BLM损伤肺纤维化模型,分别在第3、7、14以及28天行硝酸镧灌注后,制作肺组织病理标本,透射电镜观察血管内皮细胞(EC)紧密连接及镧颗粒分布。组织块培养法行大鼠肺微血管内皮细胞体外培养。体外培养的大鼠肺微血管内细胞中转染正义VEGF cDNA,采用逆转录-聚合酶链反应(RT-PCR)法检测MCP-1 mRNA的表达。结果对照组EC结构完整,基底膜呈连续线状。EC间连接紧密,镧盐颗粒未见通过EC间的紧密连接。实验组不同时间处理的大鼠均可见EC连接间隙增宽,并有高密度的镧颗粒在细胞连接间隙中线状沉淀,其中以第3天为著,分布于血管周围的内皮下区域,大部分通过基底膜到达细胞外间隙。与空白对照组比较,转染正义VEGF cDNA组肺微血管内皮细胞MCP-1 mRNA表达显著增加(P<0.05),空白对照组为0.36±0.06,转染组为1.21±0.22。结论BLM损伤肺微血管内皮细胞间紧密连接呈持续开放状态和MCP-1持续高表达,成为特异性定向诱导炎性细胞渗出和游走到组织间的病理基础,而炎性细胞持续分泌的细胞因子成为启动成纤维细胞过度增殖、诱发肺纤维化的重要因素之一。     

自发性气胸和肺代谢机能

血管紧张素转换酶(ACE)的主要作用部位是肺毛细血管内皮细胞,各种脏器的ACB总含量以肺为最高。人的肺毛细血管床约70平方米,因ACB在血管内皮细胞分布,身体内ACB的相当部分存在于肺内的说法是不过分的。关于ACB从血管内皮细胞流入血液循环中     

安多霖胶囊对高频电磁辐射损伤大鼠海马组织的保护作用

目的观察高频辐射后大鼠海马区血脑屏障(BBB)的变化和caspase-3蛋白的表达及安多霖胶囊的防护效果。方法鼠龄8周的健康SD大鼠,随机分为正常组(A组),模型组(B组)、安多霖低浓度组(C组)、安多霖高浓度组(D组)。先饲养7 d使其适应环境后,A组和B组用生理盐水灌胃,C组和D组给予不同浓度安多霖灌胃。于给药第10天,对B、C、D组大鼠进行高频辐射后24 h,断头,取材。采用透射电镜技术检测海马组织中血脑屏障结构变化。免疫组化S-P法检测海马组织中锥体细胞和齿状回颗粒细胞caspase-3蛋白表达情况。结果透射电子显微镜下可见C组硝酸镧颗粒主要沉积在毛细血管内皮细胞紧密连接(TJ)处,少量镧颗粒穿过TJ处。星形胶质细胞周围亦见少量镧颗粒沉积。D组硝酸镧颗粒主要沉积在基膜外侧,未穿过TJ处。星形胶质细胞周围亦未见有镧颗粒沉积。caspase-3表达量C组低于B组(P0.05),D组低于B组(P0.05),D组较C组低(P0.05)。结论安多霖胶囊可有效防护高频辐射损伤大鼠的学习记忆功能。     

蛋白激酶C对肺微血管内皮通透性的影响

早期急性呼吸窘迫综合征(ARDS)或急性肺损伤(ALI)是以肺毛细血管内皮细胞损伤和功能障碍导致水和蛋白向间质渗出增加为特点,而肺毛细血管内皮损伤后进一步损伤肺上皮细胞,导致肺损伤。引起肺血管内皮细胞损伤从而导致其通透性增加的因素很多,有活性氧物质(如过氧化氢H2O2),α-凝血酶,肿瘤坏死因子(TNF-α)等。蛋白激酶C(PKC)是介导其损伤作用的重要介质之一,但它们活化PKC的机制并不完全一样,PKC活化后引起血管内皮细胞损伤的机制也不尽相同。     

弥漫性肺间质纤维化的早期诊断及活动性判断

弥漫性肺间质纤维化（下简称肺纤维化）可累及肺泡上皮细胞、肺毛细血管内皮细胞及动、静脉。约３５％是因吸入粉尘、有毒气体及感染、药物（如环磷酰胺、氨甲喋呤）所致,但大多数病因不明（如特发性肺纤维化、韦格氏肉芽肿、肺泡蛋白沉着症、肺弥漫性淀粉样变性等）。肺...     

干细胞胞外囊泡在急性呼吸窘迫综合征中的治疗作用

正急性呼吸窘迫综合征(acute respiratory distress syndrome,ARDS)是在直接和间接原因触发下免疫系统与肺泡上皮毛细血管屏障相互作用,急性炎症反应引起肺泡上皮细胞及毛细血管内皮细胞损伤,导致肺蛋白通透性增加、弥漫性肺间质及肺泡水肿,进而造成难以纠正的急性低氧血症[1]。目前主要的治疗方式限于肺保护性策略即小潮气量机械通气,治疗效果欠佳,死亡率仍高达40%～70%[2]。     

流行性出血热的超微病理学

我们自1970年以来对EHF各期死亡病例的系统脏器、皮肤及肾脏的活体标本等进行了电镜观察,现结合文献就其基本超微病变作如下概述。一、微血管系统变化:本病早期主要是内皮细胞的饮液泡减少乃至消失,大液泡和微绒毛增多,质膜透过示踪的硝酸镧粒子,细胞质水肿,连接膜分离,以及基底膜疏松     

肺毛细血管压力与肺水肿

肺水肿实际上是以肺毛细血管为中心的肺微循环障碍,其形成原因归结为肺毛细血管压力(Pc)增加,内皮细胞屏障功能的削弱,或两者的结合。近年来,Tay-lor等通过直接或间接地精确测量Pc,并深入研究Pc与肺水肿形成的关系,在肺水肿的病理生理机理方面取得了重要发展。     

广州管圆线虫性肺炎的病理学研究

目的 探讨广州管圆线虫肺炎的病理变化特征。方法 大白鼠感染管圆线虫后，用组织学、组织化学及是观察肺组织的形态改变。结果 成虫寄生于肺动脉内形成虫栓，虫卵及幼虫阻塞肺毛细血管形成异物肉芽肿结节。肺血管内弹力膜断裂，坏变上动脉炎及内皮细胞呈弥漫性或簇状乳头状增生。肺部还可伴随支气管炎，肺炎及肺脓肿等改变。结论 实验性广州管圆线虫性肺炎的主要病变为成虫和虫卵的栓塞血管，血管的坏变和内皮细胞高度增生，成虫     

急性肺损伤时血中可溶型选择素-P值升高

在发生ARDS或急性肺损伤(ALI)时,中性白细胞和肺毛细血管内皮细胞的许多粘连分子介导中性白细胞肺内聚积。已证明血管内皮细胞和血小板的选择素-P(P-selection)即为一种中性白细胞与内皮细胞的粘连分子。本次研究测定了ALI患者血中可溶型选择素-P(PPS)值,并与其他肺疾患或无ALI的败血症患者进行对比。     

First annual Lamport award manuscript: Platelet-endothelial interaction and the maintenance of the microvasculature

Endothelial cells line the heart and blood vessels, and they are the principal cellular components of the capillary. The state of the microvasculature is, therefore, a reflection of the function of the endothelium. Because the capillary is the site of the blood-tissue interface, changes in endothelial cell metabolism should affect not only the vessel but also the homeostatic mechanisms of the blood and tissue fluids. The presence of circulating platelets is believed to be necessary to maintain the integrity of the capillary endothelium (and intima). The thrombocytopenic condition has been shown in vivo to cause ultrastructural and permeability changes in the microvasculature. Growing endothelial cells in culture provides an opportunity to simulate the in vivo situation and to study the responses of endothelium to various agonists, which these cells normally bind because of their direct contact with the blood. With the addition of platelets at a concentration of 10⁴–10⁵/mm³, substances (serotonin, thrombin, adenosine diphosphate, norepinephrine, epinephrine, and histamine) released by platelets or circulating in the blood following injury stimulate cultured endothelial proliferation to 150–1000% of controls. That substances so diverse in form may have similar effects suggests a common mode of action, such as the mobilization of a second messenger. Influx of calcium-45 in response to these agents was found to be 5–24 times that of controls, appears to be dose dependent, and is inhibited by preincubation with lanthanum chloride and specific blocking agents, such as Lilly 110146. Calcium as a second messenger is implicated in a variety of cellular functions including division, secretion, motility, and control of cyclic nucleotide levels. Thus, the supportive role of platelets and their secretions on endothelium may be mitogenic and regulatory, and the mobilization of intracellular calcium may be the common pathway for both events.     

Histamine induced alteration of calcium binding to microvascular endothelium as indicated by use of ionic lanthanum

To determine whether histamine's effect on microvascular permeability might be associated with altered calcium binding, the influence of histamine on lanthanum binding to vascular endothelium was assessed in the presence of verapamil. Isolated rabbit hearts were perfused firstly with histamine, secondly with histamine and verapamil, and subsequently with histamine in the presence of lanthanum and verapamil. Examination by transmission electron microscopy showed that 92% of microvessels examined contained bound lanthanum on plasma membranes, plasmalemmal vesicles, or endothelial clefts of vascular endothelium, or all three, in both atria and ventricles, which is in contrast to the low proportion (4%) of microvessels containing bound lanthanum found in the presence of verapamil alone. The enhancement of lanthanum binding was reduced by both H1 and H2 receptor antagonists. This evidence supports the hypothesis that the increase in vascular permeability with histamine may be associated with increased calcium binding to vascular endothelial membranes and that both H1 and H2 receptors play a part in this activity.     

Ultrastructural observations on experimental shock lung

Intercellular junctions in the alveolar epithelium and in the capillary endothelium in the dogs after hemorrhagic shock (mean BP 40 mm Hg for 3 hours) and from control dogs were observed in the electron microscope using the freeze-fracture and etch technique. Following shock, tight junctions (zonulae occludentes) in the alveolar epithelium which were well developed with may strands in control animals showed alterations in substructure. Some desintegration and disappearance of junctional strands in "focal" regions were occasionally observed in the endothelium as well. The increased pulmonary capillary permeability observed physiologically after hemorrhagic shock may be explained by such alterations of endothelial zonulae occludentes.     

四周四氧嘧啶糖尿病大鼠主动脉超微结构和通透性变化

目的 了解糖尿病早期主动脉超微结构及通透性变化。方法 ４周四氧嘧啶糖尿病大鼠主动脉按透射电镜观察的要求进行固定、包埋、切片、染色及镧通透性检测的要求进行固定、染色、包埋和切片后,进行透射电镜观察。结果 糖尿病大鼠主动脉平滑肌细胞线粒体肿胀,有镧进入;内皮细胞紧密连接处有镧进入。结论 糖尿病早期主动脉平滑肌细胞膜及其线粒体膜通透性增加,线粒体肿胀,内皮通透性增加。     

The structure of scorbutic regenerating capillaries in skeletal muscle wounds

The purpose of this investigation was to characterize scorbutic regenerating capillaries in skeletal muscle wounds and to compare their structure with that of normal regenerating capillaries and mature (nonwound) scorbutic capillaries. Wounds were created in the cremaster muscle of scorbutic guinea pigs. The capillary fringe areas of the wounds were examined at intervals of 3 to 16 days postoperatively by light and electron microscopy. Nonscorbutic animals served as controls. No significant change was noted between the perivascular collagen of scorbutic and nonscorbutic wounds. Organelle changes were similar to those reported in nonwound scorbutic endothelium. Specific structural effects noted in the scorbutic wound capillaries were a slower rate of ingrowth of the capillary fringe into a wound; decreased sprouting and proximal anastomosing of the growing vessels; a bulbous-shaped capillary tip with numerous thin spots in the endothelium; ready ingress of tracer substances to the capillary tip; and, the presence of pale endothelial cells of unknown function. The capillary basement membrane surrounded all portions of the endothelium and did not exhibit any discontinuities except around cytoplasmic extrusions. This study showed that scorbutic regenerating wound capillaries differ significantly in their structure from normal regenerating capillaries and mature (nonwound) scorbutic capillaries. Application of the law of Laplace (T = P × R) to the bulbous scorbutic capillary tips allows us to theorize that increased endothelial wall tension accounts for their fragility.     

Age-related changes in the hepatic sinusoidal endothelium impede lipoprotein transfer in the rat

The mechanisms for the association of old age with post-prandial hyperlipidemia and atherosclerosis are not well understood. Post-prandial hyperlipidemia has emerged as a significant risk for atherosclerosis. The liver is the central organ for lipoprotein metabolism. The initial step in the hepatic uptake of post-prandial lipoproteins is their transfer from the hepatic sinusoidal capillary lumen across the hepatic sinusoidal endothelium into the space of Disse. Here, they access hepatocytes for receptor-mediated uptake. We proposed that fenestrations (pores) within the hepatic sinusoidal endothelium filter lipoproteins on the basis of size. Recently we discovered age-related changes in the sinusoidal endothelium (pseudocapillarization), including reduction in the porosity of the endothelium. Using the impulse response technique in perfused rat livers, we found that aging is associated with impaired hepatic transendothelial transfer of chylomicrons with diameters smaller than those of fenestrations. In conclusion, age-related pseudocapillarization of the hepatic sinusoidal endothelium provides a novel mechanism for the association of old age with impaired hepatic lipoprotein metabolism and with atherosclerosis.     

Differences in function and structure of the capillary endothelium in the supraoptic nucleus and pituitary neural lobe of rats. Evidence for the supraoptic nucleus as an osmometer

The physiology and structure of capillary endothelial cells in the hypothalamic ventromedial and supraoptic nuclei and pituitary neural lobe were evaluated with quantitative methods and compared. The capillary endothelial cells in the ventromedial nucleus were used as an index of blood-brain barrier endothelium in cerebral gray matter; this endothelium has relatively low surface area and low permeability to tracer solutes. The permeability X surface area product of endothelial cells for a neutral amino acid, 14C-alpha-aminoisobutyric acid (AIB), in the ventromedial nucleus was similar to the value for supraoptic nucleus and was several hundred times smaller than in the neural lobe. The supraoptic nuclei and neural lobe had exceptionally large capillary surface areas, but dissimilar rates of blood flow and transendothelial influx of AIB. Differences in permeability of the endothelial cells between these two structures correlated closely with their marked dissimilarities in morphology. The neural lobe endothelium had numerous fenestrations (five per capillary cross-section) and vesicular profiles (twice as many as supraoptic nucleus), two features commonly associated with high capillary permeability. The capillary endothelium of the supraoptic nucleus was that of a typical blood-brain barrier structure having intercellular junctions that appeared tight, no fenestrations, and few cytoplasmic pits and vesicles. The unusually large capillary surface area of the supraoptic nucleus and low rate of solute flux across its endothelial cells make this nucleus a unique structure in which rapid changes in tissue volume may occur in response to small perturbations in plasma osmolality. The findings implicate the supraoptic nucleus as an osmotically sensitive detector or 'osmometer' in neuroendocrine regulation of body fluid homeostasis.     

克山病区低硒粮饲养大鼠的心肌细胞超微结构及膜通透性改变的实验观察

本实验用克山病区低硒粮喂养大鼠,使动物处于低硒状态,同时增设补硒组和常规饲料组作为对照。饲养二个月后,应用电镜和示踪剂分别观察其心肌细胞超微结构及膜通透性的改变。低硒组大鼠心肌细胞膜不完整,镧颗粒进入细胞内,但线粒体内罕见。质膜经钌红染色呈中等电子密度的不均匀窄带,并经质膜破损处进入心肌细胞内。实验结果表明,低硒可引起大鼠早期心肌细胞超微结构及膜通透性的改变。     

Permeability of the small intestine after intra-arterial injection of histamine-type mediators and irradiation.

Permeability and selectivity of rabbit small intestine were estimated by a perfusion technique after intra-arterial injection of histamine-type mediators and intestinal irradiation. It was shown that the histamine-type mediators caused an increase in capillary permeability which produced an overall moderate increase in transmucosal permeability with a moderate loss of selectivity. Local intestinal irradiation caused a very marked increase in permeability and a profound loss of selectivity. It was felt that this was produced partly by an increase in capillary permeability but largely by damage to the epithelial basement membrane. It is concluded that the intestinal capillary endothelium is both rate-limiting and selective, though not to a major degree in either case. The epithelial basement membrane, however, appears to be both rate-limiting and markedly selective.     

Pulmonary capillary filtration and reflection coefficients in the adult rabbit

Using an isolated, Ringer-perfused lung preparation, we measured values of the filtration coefficient and reflection coefficients of NaCl, mannitol, sucrose, raffinose, inulin, and albumin for the pulmonary capillary endothelium of adult rabbits. We found a filtration coefficient value of 1.00 × 10^?3 cm³ sec^?1 cm H₂O^?1. When this value is normalized for the estimated exchange area it is similar to other reported lung K_f values normalized in the same way. Using an osmotic transient technique we measured the reflection coefficients for the test molecules mentioned. NaCl, mannitol, sucrose, and raffinose all had small values (about 0.05) which were not significantly different from one another. Based on this we assume that using these molecules we measured the kinetics of osmotic flow across cell membranes and not through capillary endothelial pores (capillary σ = 0 for these molecules). Correcting inulin and albumin data for this “cell” effect, we estimate σ_inulin = 0.09 and σ_albumin = 0.35 for adult pulmonary capillaries. These results are consistent with a two-pore model of the pulmonary capillary endothelium: (a) pores in the endothelial cell membranes having dimensions typical of cell membrane pores and contributing very little to fluid transport, and (b) pores through the endothelium having a radius of about 100 Å and through which virtually all induced fluid flux occurs. Our data, however, do not rule out other multipore models of the capillary endothelium which have been proposed.