慢性缺氧时肺腺泡内动脉结构变化与血流动力学变化的关系

在用低压舱模拟连续低压缺氧不同时间的大鼠模型上,观察分析了肺腺泡内动脉结构重建变化与肺循环血流动力学变化的关系。结果表明:缺氧早期(24h后),肺腺泡内动脉即有明显肌化(肌性动脉段增多,非肌性动脉段减少)。随缺氧时间延长,肺腺泡内动脉肌化与肺动脉压增高及右心室代偿性肥厚密切相关。构成肺腺泡内动脉的三种血管段随缺氧时间延长有不同变化趋势,反映出缺氧早期肌性动脉段增多主要经原有部分肌性动脉段转变为肌性动脉段的短捷途径;以后非肌性动脉段经部分肌性动脉段转变为肌性动脉段逐渐成为主要途径。     

野百合碱引起肺血管重建的观察

目的和方法:一次性腹腔注射野百合碱(MCT)(60mg/kg体重),建立大鼠肺心病模型。利用光镜、电镜技术测量观察肺血管重建时内皮细胞、肺小动脉、心脏等变化情况。从形态学改变方面探讨肺动脉高压时肺血管重建的机制。结果:肺血管内皮细胞损伤;小血管血小板性血栓形成;动脉弹力膜断裂;血管平滑肌细胞增生、迁移、转型;肺血管肌化、改建,其中以肺腺泡内动脉的变化尤为突出。右心室明显肥大。结论:一次性注射MCT即可引起肺血管损伤、重建,导致肺心病;在此过程中,血管内皮细胞起着关键作用;肌化增强的肺动脉中膜平滑肌细胞可能来源于周细胞和原位的中间细胞。     

急性缺氧对大白鼠肺动脉压和颈动脉压的影响

早已有人发现肺血管和体血管对缺氧的反应有所不同。Bergofsky报导在缺氧时这两类血管平滑肌细胞膜的阳离子主动运转系统发生不同的变化;也有人报导缺氧抑制了体血管平滑肌中三磷酸腺苷(ATP)的氧化生成,从而减弱其收缩,同时却能加速肺血管平滑肌的酵解,增加ATP,为肺血管平     

VEGF和PCNA在慢性低氧性肺动脉及高压大鼠主动脉、肺动脉平滑肌细胞中表达

目的研究慢性低氧性肺动脉高压(PAH)发生过程中,血管内皮生长因子(VEGF)及细胞核增殖抗原(PCNA)在体循环血管、肺循环血管平滑肌细胞中的表达。方法利用低压缺氧舱建立大鼠缺氧性肺动脉高压模型。实验分为3组即正常氧组、缺氧2wk组和缺氧3wk组。用免疫组化染色和图像分析,检测主动脉、肺动脉主干及肺内小动脉平滑肌细胞中VEGF及PCNA的表达量。结果VEGF在正常氧组大鼠的主动脉、肺动脉主干及肺内小动脉平滑肌内均有表达;缺氧组大鼠肺动脉主干及肺内小动脉平滑肌细胞内VEGF的表达明显增强并随着缺氧时间的延长而增加;主动脉平滑肌内VEGF的表达量无明显变化。PCNA在正常氧组大鼠的主动脉、肺动脉主干及肺内小动脉平滑肌内均有微弱表达;但缺氧时只有肺小动脉平滑肌内其表达量增加;主动脉、肺动脉主干平滑肌内PCNA的表达量无明显差别。结论在缺氧性肺动脉高压的发生过程中,VEGF在体循环血管、肺循环血管平滑肌细胞中的表达量具有差异性,提示其可能在肺动脉高压形成过程中起重要作用。     

伴肺动脉高压的先天性心脏病患儿肺组织病理学观察

目的　探讨左向右分流型先天性心脏病患儿肺组织的病理形态学改变、超微结构改变与肺动脉高压 (pulmonaryhy pertension ,PH)形成的关系。方法　应用光镜、电镜、组织化学染色 ,对 4 1例先心病患儿肺组织及肺各级小动脉进行研究、分析。结果　伴有PH的肺组织各级小动脉 (包括部分肌型及肌型动脉 )数量增加、管壁增厚、管腔狭窄 ,尤以中重度PH患者显著 ,主要表现血管中膜平滑肌 (SMC)和内皮细胞 (EC)增生 ,内弹力膜增厚 ,外膜胶原纤维增多。先天性心脏病患儿肺组织内无肌型小动脉肌化、部分肌型及肌型小动脉数量增加 ,随着PH的增高 ,差异有显著性 (P <0 0 1)。超微结构改变包括 :①肺泡隔纤维化逐渐明显 ,胶原纤维增生 ;②小动脉中膜SMC层数明显增加 ,SMC细胞面积增大 ,核染色质增粗 ,细胞间间隙明显增宽 ,血管外膜胶原纤维高度密集 ;③小动脉血管内皮细胞增生呈高柱状 ,细胞线粒体肿胀、空泡化 ,吞饮小泡多见 ;④毛细血管充血、瘀血 ,基膜明显增厚。结论　先心病引起缺氧导致肺血管重建 ,使肺血管阻力增加 ,是PH形成的关键因素 ,肺毛细血管的超微结构病变所致微循环障碍更加促进了PH的发生、发展。     

慢性缺氧进程中大鼠肺动脉羟脯氨酸含量的动态变化

本研究组业已报道,随着缺氧时间的延长,大鼠肺动脉压持续上升,肺血管顺应性明显下降,表明肺血管壁弹性减低是缺氧性肺动脉高压形成的重要原因之一。在以往的实验中还观察到,缺氧40天时大鼠肺动脉压往往有回降趋势,同时肺血管顺应性则有所增加。为此,我们对慢性缺氧进程中大鼠肺动脉羟辅氨酸(HyP)含量     

慢性肺动脉高压肺血管力学特性的评价

本文以风心病二尖瓣病变合并被动性肺动脉高压为研究对象,借助右心导管技术和利用压力波形面积确定动脉顺应性的改进方法,通过测定肺血管阻力和顺应性,以评价慢性肺动脉高压肺血管力学特性的变化规律。发现慢性肺动脉高压患者肺动脉血管阻力明显升高（P＜0.01）;而反映血管壁固有结构的零压顺应性Co明显下降(P＜0.01),与术前肺动脉平均压呈显著负相关(r＝－0.745P＜0.05);扩血管药物试验提示不同程度肺动脉高压组的肺血管阻力均有显著下降(P＜0.01),轻度肺高压组零压顺应性和平均压顺应性均明显升高(P＜0.01);而重度肺高压组零压顺应性Co无明显变化(P＞0.05)。由此我们认为慢性肺高压肺血管都存在不同程度的重建,肺血管外周血管阻力和顺应性是影响其肺动脉压力水平的主要因素。     

慢性低氧性肺动脉高压大鼠肾上腺髓质素前体N端20肽的变化

目的：探讨慢性低氧性肺动脉高压和肺血管结构重建时肾上腺髓质素前体N端20肽（PAMP）的变化。方法:将18只雄性Wistar大鼠随机分为对照组和低氧组，每组各9只。常压低氧2周后，以右心导管法测定肺动脉平均压（mPAP），检测右心室与左心室加室间隔比值 ［RV/(LV+S)］，观测肺血管显微和超微结构的变化。并且以放免法测定血浆中PAMP含量，以免疫组化法检测肺组织中PAMP表达，以原位杂交检测肺组织中肾上腺髓质素（ADM） mRNA的表达。结果: 低氧组大鼠mPAP及RV/（LV+S）均明显高于对照组（均P<0.01）。光镜下，肺小血管肌化程度明显增强，肺中、小型肌型动脉相对中膜厚度明显增加。电镜下，肺腺泡内动脉内皮细胞增生、肿胀，内弹力层粗细不均，平滑肌细胞肥厚、向合成表型转化。并且低氧组大鼠血浆PAMP含量明显高于对照组（P<0.01），肺动脉PAMP表达和ADM mRNA表达均明显增强。结论：低氧后肺动脉PAMP表达和血浆PAMP含量的上调可能参与了慢性低氧性肺动脉高压和肺血管结构重建的形成。     

高肺血流量所致肺动脉高压大鼠肺血管结构和气体信使分子的变化

目的:探讨高肺血流量所致肺动脉高压大鼠肺血管结构和两种气体信使分子的变化。方法:对大鼠行腹主动脉-下腔静脉分流术。11周后,以右心导管法测定肺动脉平均压(PAMP)。检测右心室/体重(RV/BW)和右心室/左心室+室间隔(RV/LV+S)比值。观测肺血管显微及超微结构的变化。并且以分光光度计测定血浆一氧化氮(NO)和一氧化碳(CO)含量,以免疫组织化学方法检测肺动脉内皮细胞内皮型NO合酶(eNOS)和平滑肌细胞血红素加氧酶-1(HO-1)的表达。结果:分流组大鼠PAMP、RV/BW及RV/(LV+S)比值明显高于对照组(P均<001)。光镜下,肺小血管肌化程度明显增强,肺中、小型肌型动脉相对中膜面积及厚度明显增加。电镜下,肺腺泡内动脉内皮细胞增生、变性,内弹力层粗细不均,平滑肌细胞肥厚、向合成表型转化。并且分流组大鼠血浆NO含量明显高于对照组(P<001),肺动脉内皮细胞eNOS表达明显增强。而分流组大鼠血浆CO含量和肺动脉平滑肌细胞HO-1表达与对照组相比无明显变化。结论:肺血管结构重建是左向右分流所致肺动脉高压的重要病理基础,NO体系可能在其形成中起重要的调节作用。     

缺氧大鼠肺内动脉壁FN及LN的改变

目的　利用大鼠常压缺氧模型 ,采用形态计量学方法 ,系统观察缺氧大鼠肺动脉壁FN及LN的改变 ,进一步探讨缺氧性肺血管组织重建的机制。　方法　利用常压缺氧舱建立大鼠缺氧模型 ,取肺分别进行免疫组织化学染色和电镜观察。　结果　缺氧后肺动脉壁上FN及LN均增加 ,这一变化在缺氧 7d时最明显 ,且FN增加的程度及含量远远高于LN。电镜观察显示 ,肺动脉中膜平滑肌细胞有由收缩表型转化为合成表型的倾向。　结论　肺动脉壁上FN及LN增加 ,不仅可以增加血管紧张性及血管壁厚度 ,同时也为诱导中膜平滑肌细胞表型转换及增生提供了条件     

Remodeling of fetoplacental arteries in rats due to chronic hypoxia

The increased fetoplacental vascular resistance due to chronic hypoxia cannot be explained by simple hypoxic vasoconstriction, as it sustains to some degree after recovery in normobaric environment. To verify a hypothesis that fetoplacental arteries undergo remodeling of their walls similar to remodeling of pulmonary arteries in hypoxic pulmonary hypertension, we used a model of the chronically hypoxic rat placenta. Han Wistar pregnant rats were exposed to 14-day hypoxia (10% of oxygen) during the 6th to 19th day of pregnancy. Chronic hypoxia elicited in both intraplacental (prelabyrinthine) and chorionic plate (insertion) arteries significant narrowing of their lumina. Irregular thickening of their adventitia due to an increase in collagen fibers as well as ground substance was observed; reticular fibers were fragmented. Because of remodeling of fetoplacental arteries, a model of chronically hypoxic rat placenta could simulate human preplacental hypoxia and consequent effects.     

Acute and chronic hypoxia as well as 7-day recovery from chronic hypoxia affects the distribution of pulmonary mast cells and their MMP-13 expression in rats

Chronic hypoxia results in pulmonary hypertension due to vasoconstriction and structural remodelling of peripheral lung blood vessels. We hypothesize that vascular remodelling is initiated in the walls of prealveolar pulmonary arteries by collagenolytic metalloproteinases (MMP) released from activated mast cells. Distribution of mast cells and their expression of interstitial collagenase, MMP-13, in lung conduit, small muscular, and prealveolar arteries was determined quantitatively in rats exposed for 4 and 20 days to hypoxia as well as after 7-day recovery from 20-day hypoxia (10% O2). Mast cells were identified using Toluidine Blue staining, and MMP-13 expression was detected using monoclonal antibody. After 4, but not after 20 days of hypoxia, a significant increase in the number of mast cells and their MMP-13 expression was found within walls of prealveolar arteries. In rats exposed for 20 days, MMP-13 positive mast cells accumulated within the walls of conduit arteries and subpleurally. In recovered rats, MMP-13 positive mast cells gathered at the prealveolar arterial level as well as in the walls of small muscular arteries; these mast cells stayed also in the conduit part of the pulmonary vasculature. These data support the hypothesis that perivascular pulmonary mast cells contribute to the vascular remodelling in hypoxic pulmonary hypertension in rats by releasing interstitial collagenase.     

Hypoxia and incorporation of 3H-thymidine by cells of the rat pulmonary arteries and alveolar wall.

In the pulmonary arterial circulation hypoxia produces increase in thickness of the medial muscle coat as well as of the adventitia; in addition muscle appears in smaller arteries than is normal and the number of small arteries that fill on Micropaque-gelatin injection is reduced. To assess the role of hyperplasia in these changes, the uptake of 3H-thymidine by the cells of the pulmonary arterial wall has been studied in rats exposed to hypobaric hypoxia (exposure to 380 torr) after 1, 3, 5, 7, 10, and 14 days. Using autoradiographs of 1-micron sections, the glutaraldehyde-distended intrapulmonary hilar muscular artery, the peripheral, intraacinar arteries less than 100 micron in external diameter, and the alveolar wall had different patterns of uptake. In the hilar pulmonary artery, after 24 hours of exposure, the labeling index for adventitial fibroblasts is increased eightfold over the control value, and for endothelial cells, threefold, while for medial smooth muscle cells, there is a gradual and small increase to Day 14. Newly muscularized intraacinar arteries are first apparent at Day 3, when they comprise 40% of the intraacinar arteries, increasing to 80% at Day 7. No decrease in density of arteries is found. Uptake of 3H-thymidine by new muscle cells is not apparent until Day 5 when labeling is maximum. The endothelial cells of the newly muscularized arteries show an increased labeling index only at Days 7 and 10. The veins and normally muscular arteries do not show these changes. In the alveolar walls, the concentration of labeled cells is significantly above the control value at Days 3, 5, and 7 and significantly below, at Day 14. At this level, the interstitial, epithelial, and endothelial cells contribute to the increase.     

肾上腺髓质素缓解大鼠低氧性肺动脉高压

目的探讨肾上腺髓质素(ADM)对大鼠低氧性肺动脉高压的防治作用及机制。方法雄性Wistar大鼠18只,分为对照组、低氧组和低氧 ADM组,每组6只。持续皮下注射ADM1-50后,测定平均肺动脉压(mPAP)、右心室肥大指数RV/(LV S)、肺小动脉病理及形态计量学和体循环平均压(mSBP),放免法测定肺动脉血浆ADM水平,原位杂交测定肺动脉ADMR mRNA的表达。结果①低氧组大鼠mPAP,RV/(LV S),管壁厚度与血管外径比值(MT%)及管壁面积与血管面积比值(MA%)均显著升高(P<0.01);ADM组显著缓解以上变化(P<0.01)。②低氧组与低氧 ADM组肺动脉血浆ADM浓度均高于对照组,且低氧 ADM组较低氧组ADM浓度低(P<0.05)。③低氧组与低氧 ADM组的ADMR mRNA表达较对照组增强(P<0.01)。结论持续皮下注射ADM对慢性低氧所致的肺动脉高压及肺血管重塑有预防和部分逆转作用。     

肺动脉平滑肌细胞凋亡在大鼠低氧性肺动脉重构自然逆转中的作用及分子机制

目的:研究肺动脉平滑肌细胞(pulmonary arterial smooth muscle cells,PASMCs)凋亡在低氧性肺动脉重构自然逆转中的作用,并探讨其可能机制。方法:24只SD大鼠随机均分为常氧4周组、低氧4周组、低氧4周后复氧1周组及复氧6周组。分别检测右室收缩压(right ventricular systolic pressure,RVSP)、肺动脉中膜厚度(medial thickness,MT)和中膜面积(medial area,MA),以及肺动脉中膜自噬、凋亡等在低氧-复氧中的变化。大鼠原代PASMCs分为常氧48 h组、低氧48 h组、低氧48 h后复氧24 h组及常氧72 h组,观察PASMCs凋亡和自噬在低氧-复氧中的变化。再将PASMCs分为常氧72 h组、低氧48 h后复氧24 h组及低氧48 h+氯喹(自噬抑制剂)干预后复氧24 h组,观察PASMCs低氧阶段的自噬对其复氧阶段凋亡的影响。结果:(1)低氧使大鼠RVSP、右室肥厚指数、MT及MA显著升高(P0.05);复氧后上述指标逐渐降低。(2)低氧使肺动脉中膜LC3表达升高,P62表达降低,复氧后上述分子的表达逐步恢复正常。低氧显著降低了中膜cleaved caspase-3的表达,复氧1周其表达显著高于低氧组。(3)低氧期原代PASMCs cleaved caspase-3/PARP的表达显著低于常氧组,复氧后其表达明显升高(P0.05);PASMCs LC3和P62的表达在低氧期显著降低(P0.05)。(4)抑制了PASMCs低氧阶段的自噬后,其复氧阶段cleaved caspase-3/PARP表达显著降低(P0.05)。结论:PASMCs的凋亡参与了低氧性肺动脉重构的自然逆转;复氧期PASMCs凋亡的发生可能与其低氧期的自噬有关。     

长期烟雾暴露对大鼠肺血管重塑及转化生长因子-β1表达的影响

目的:观察长期吸烟对大鼠肺血管重塑及转化生长因子-β1(TGF-β1)的影响,探讨其发生的可能机制。方法:将36只健康SD雄性大鼠随机分为对照组、烟雾暴露2周(S-2W)和烟雾暴露12周(S-12W)组。苏木精-伊红染色和α-平滑肌肌动蛋白染色切片观察肺血管重塑的程度,免疫组化法检测增殖细胞核抗原(PCNA)和TGF-β1在肺动脉的相对表达;RT-qPCR检测肺动脉TGF-β1的mRNA表达。结果:随烟雾暴露时间延长,模型组血管壁厚度和血管直径比值(WT%)和完全肌化血管比例均较对照组明显增大,差异具有统计学显著性(P0.01)。模型组的PCNA及TGF-β1蛋白表达水平均较对照组增大,且两模型组之间差异有统计学显著性(P0.01)。与对照组比较,模型组TGF-β1的mRNA表达均显著增加(P0.05),其中S-2W组和S-12W组之间的差异亦有统计学显著性(P0.05)。TGF-β1的mRNA表达与WT%和完全肌化血管比例呈显著正相关(P0.01);TGF-β1的mRNA表达与PCNA蛋白表达呈显著正相关(P0.01)。结论:长期烟雾暴露可导致大鼠肺血管重塑的形成,其机制可能与吸烟上调大鼠肺血管TGF-β1的mRNA表达,诱导肺血管平滑肌细胞增殖有关。     

Pulmonary artery adventitial changes and venous involvement in primary pulmonary hypertension.

Primary pulmonary hypertension (PPH) is associated with a spectrum of structural changes in the pulmonary arteries: increased medial thickness, eccentric and concentric intimal thickening, obliteration and recanalization of arteries, and appearance of plexiform and dilatation lesions. The purpose of the present study was to further characterize these structural changes with particular emphasis on arterial adventitial thickness and alterations in the walls of the pulmonary veins. In addition, to determine whether the characteristic structural changes of PPH were size related, each was related to external diameter. With quantitative techniques, the pulmonary vasculature of 19 patients with PPH and 7 controls was examined by light microscopy. In all 19 patients, we found a striking increase in adventitial, as well as intimal and medial, thickness in arteries of all sizes when compared with controls (P < 0.05). In addition, we found intimal and adventitial thickening of pulmonary veins < 250 mu in diameter in approximately half of the PPH cases (P < 0.05). The frequency of arterial obliteration, concentric intimal thickening, and recanalization was 16, 18, and 11 of 19 cases, respectively. These changes were most prevalent in arteries less than 200 mu in diameter whereas eccentric intimal thickening and plexiform lesions occurred in 15 and 6 of the patients, respectively, and were most widespread in arteries > 200 mu. We conclude that remodeling of the pulmonary vasculature in PPH routinely includes thickening of the arterial adventitia and frequently also includes changes in the walls of the pulmonary veins. The finding that recanalization occurs predominantly in the smaller arteries whereas eccentric intimal thickening occurs mainly in the larger ones suggests that recanalization should not be considered a consequence of thromboemboli but may also occur at sites of more fibrotic intimal change.     

磷酸肌醇3－激酶调控缺氧诱导因子1α对大鼠缺氧性肺动脉高压的作用

目的:观察缺氧性肺动脉高压（HPH）大鼠肺组织中蛋白激酶B（AKT））和缺氧诱导因子1α(HIF-1α)以及血管内皮生长因子(VEGF)的表达，探讨磷酸肌醇3-激酶（PI3K）通路与HIF-1α和VEGF的关系及其在HPH发病中的可能机制。 方法:40只成年雄性Wistar大鼠随机分成对照组、低氧3、7、14和21 d组，每组8只，测各组大鼠平均肺动脉压（mPAP）、右室肥大指数（RVHI）、血管形态学指标Western印迹检测磷酸化AKT(P-AKT)；原位杂交和免疫组化检测HIF-1α的表达。免疫组化检测P-AKT和VEGF水平。 结果:① 低氧7 d起大鼠mPAP、管壁厚度与血管外径比值及管壁面积与血管面积比值分别为(23.53 ±1.78)mmHg, (45.5±3.1)%和(54.7±3.2)%,与对照组［(16.15±1.97)mmHg、(36.8±2.5)%、(63.2±2.5)%］比较差异显著(P＜0.05),低氧14 d起稳定于高水平;低氧14 d RVHI为(26.5±2.9)%,与对照组［(22.9±2.2)%］比较差异也显著(P＜0.05)。②p-AKT蛋白在对照组表达不明显，缺氧3 d后表达上升，与对照组比较差异显著(P＜0.05)，且在缺氧3 d、7 d、14 d、21 d组肺小动脉内膜、中膜表达均为阳性。③HIF-1α蛋白对照组表达不明显，缺氧3 d、7 d、14 d、21 d组肺血管内膜均为阳性，肺血管中膜，缺氧3 d组表达开始升高（0.209±0.009），与对照组比较差异显著(P＜0.05),缺氧7 d达高峰（0.232±0.008,P＜0.05），14 d和21 d下降；HIF-1α mRNA在对照组肺动脉血管壁内表达弱阳性，缺氧3 d和7 d肺血管中表达无明显变化，与对照组比较差异无显著(P＞0.05)。缺氧14 d后表达增高(0.305±0.104, P＜0.05),并持续维持于高水平。VEGF蛋白水平在低氧7 d显著高于对照组(0.188±0.018, P<0.05),14 d达高峰(0.238±0.017, P<0.05)。相关分析表明mPAP与肺血管重塑呈正相关(r=0.983, P<0.01)。在肺小血管内膜:P-AKT与 HIF-1α蛋白呈正相关(r=0.883, P<0.01)， HIF-1α与VEGF蛋白呈正相关(r=0.897, P<0.01)。 结论:磷酸化AKT与HIF-1α和VEGF均在大鼠HPH的发病机制中发挥作用。磷酸化AKT可能通过使HIF-1α蛋白表达增加的方式上调HIF-1α，进而上调下游目标基因VEGF，导致HPH的发生和发展。     

低氧诱导肺动脉内皮细胞转分化的初步机制研究

目的观察低氧培养下肺动脉内皮细胞转分化现象及转化生长因子β1（TGF-β1）对内皮细胞转分化的作用机制。方法通过组织贴壁法分离培养的肺动脉内皮细胞,分别在常氧（含21％O2、5％CO2、74％N2混合气体）和低氧（含1％O2、5％CO2、94％N2混合气体）条件下培养1、4、7d,检测细胞形态表型变化和TGF—β1表达水平。不同TGF—β1或其抑制剂SD-208刺激肺动脉内皮细胞,检测平滑肌细胞标准蛋白仅．平滑肌肌动蛋白（α—SMA）的表达,来判断肺动脉内皮细胞转分化情况。结果低氧培养铺路石样肺动脉内皮细胞逐步向α—SMA高表达的多角形细胞改变,且TGF-β1表达水平明显增高。TGF—β1能刺激肺动脉内皮细胞可出现αSMA表达的增加,SD-208可抑制上述改变。结论低氧可促进肺动脉内皮细胞向平滑肌样细胞转分化;TGF-β1在此讨稃中发挥重萼作用。