维甲酸对高氧暴露下原代培养的胎鼠肺泡Ⅱ型上皮细胞和成纤维细胞增殖与凋亡的影响

探讨高氧暴露对原代培养的胎鼠肺泡Ⅱ型上皮细胞（AECⅡ）、成纤维细胞（LFs）增殖和凋亡的影响以及维甲酸（RA）的保护作用机制。通过建立高氧暴露原代培养的胎鼠AECⅡ和LFs模型,以RA作为干预方式,采用流式细胞术（膜联蛋白V—PI双标记）检测AECⅡ和LFs凋亡,Western印迹检测AECⅡ增殖细胞核抗原（PCNA）、p53及caspase-3表达和LFs PCNA表达。结果发现：（1）与空气对照比较,高氧暴露12h,膜联蛋白V（＋）PI（-）和膜联蛋白V（＋）PI（＋）标记AECⅡ数均显著升高（14．41±1．15 vs 2．80±0．19,P＜0．01;61．07±3．06 vs 1．49±0．11,P＜0．01）;RA对空气暴露下AECⅡ坏死、凋亡无明显影响,但明显下调高氧暴露下膜联蛋白V（＋）PI（-）和膜联蛋白V（＋）PI（＋）标记AECⅡ数（8．04±0．79 vs 14．41±1．15,P＜0．01;27．57±2．32 vs 61．07±3．06,P＜0．01）。（2）高氧、RA对LFs坏死、凋亡无明显影响。（3）高氧暴露12h,明显降低AECⅡPCNA表达（P＜0．01）,显著提高其p53（P＜0．01）和caspase-3活性片段（P＜0．01）表达;RA显著上调高氧暴露下AECⅡPCNA表达（P＜0．01）,下调其p53和caspase-3活化片段表达（P＜0．01）。（4）高氧、RA对LFs PCNA表达无明显影响。由此提示,高氧暴露,导致AECⅡ大量凋亡、坏死,增殖受到抑制,同时,LFs所受影响较小,两种细胞对高氧暴露的差异性行为可能是导致未成熟肺组织异常重构的重要原因;RA通过降低AECⅡ凋亡、坏死从而对高氧肺损伤具有保护作用。     

足月妊娠PGE2及其受体表达与引产成功率的关系

目的研究足月妊娠子宫平滑肌与蜕膜组织中前列腺素E2（Prostaglandin E2,PGE2）的浓度、子宫平滑肌中PGE2受体-2（PGE2 recepor-2,PGER2）蛋白的表达与缩宫素引产成功率的关系。方法选择缩宫素引产成功与缩宫素引产失败的孕妇,于剖宫产术中取子宫平滑肌及子宫蜕膜组织。分别行ELISA法检测组织匀浆中PTGE2的浓度,Western blot检测子宫平滑肌中PTGER2蛋白的表达。结果缩宫素引产成功组比缩宫素引产失败组子宫平滑肌、子宫蜕膜组织中PTGE2浓度显著增高（P〈0．01）;缩宫索引产成功组比缩宫素引产失败组子宫平滑肌组织中PTGER2蛋白的表达也明显增高（P〈0．01）。结论子宫平滑肌与蜕膜组织中PTGE2浓度、子宫平滑肌组织中PTGER2蛋白的表达量与缩宫素引产成功率关系密切。     

急进高原健康人动脉血浆降钙素基因相关肽等物质含量的变化

目的：观测急进高原低氧环境,降钙素基因相关肽等6种血管活性多肽含量的动态变化,探索人体在急性缺氧时的生理调节过程。方法：用放射免疫法测定41名健康青年男性志愿者在海拔1100m世居地,进入海拔2260m3月、海拔3780m1d、5d和15d动脉血浆降钙素基因相关肽（CGRP）,内皮素（ET）等物质的含量。结果：动脉血浆舒血管物质CGRP、CNP、β-EP和NT浓度明显增加。而缩血管物质ET的含量在进入海拔3780m5d时显著下降（与海拔1100m、2260m和3780m1d相比差别显著,P〈0．01）,NPY含量不同海拔间无显著性差异。结论：动脉血中血管活性物质含量变化为血管舒张因子的含量显著增加,血管收缩因子含量明显下降,表明人体在急性缺氧时,血管扩张在肺循环对低氧的生理性调节中占主导地位。     

兔全脑缺血动物模型复制方法的改进

目的：探索兔全脑缺血动物模型复制方法的改进。方法：在Pulsinelli全脑缺血动物模型上作了部分改进,直接暴露处理双侧颈总动脉的椎动脉,在缺血期间将MAP维持在恒定范围。结果：本模型对血压、动脉血气无显著影响（P＞0．05）,兔全脑缺血3天后海马CA1区正常神经元密度显著低于正常兔（P＜0．01）,正常神经元丢失45％。结论：本法复制兔全脑缺血模型,缺血完全,操作简便。     

钙激活氯通道对大鼠脑基底动脉舒缩活动的影响

本文旨在观察钙激活氯通道(calcium-activated Cl-channels,CaCCs)在大鼠脑基底动脉舒缩活动中的作用。应用压力肌动图技术观察给予不同药物干预后大鼠脑基底动脉血管段直径的变化。结果显示:(1)脑基底动脉管腔内压力为0~100 mmHg时,压力诱发引起的脑血管舒缩活动的比例为78.6%(n=28),且血管的收缩比舒张反应更快。(2)脑基底动脉管腔内压力为60 mmHg时,振幅平均值为(62.6±6.4)μm(n=22),频率平均为(8.0±2.3)次/5 min(n=22)。(3)在细胞外液无钙时,血管段舒缩活动减弱。(4)在细胞外液加入L-型钙通道阻断剂尼莫地平,血管段舒缩活动减弱。(5)在细胞外液加入CaCCs通道阻断剂尼氟灭酸(niflumic acid,NFA)和NPPB[5-nitro-2-(3-phenylpropylamine)benzoic acid],压力诱发的血管舒缩活动减弱,并使脑基底动脉血管保持持续舒张。以上结果提示,管腔内压力诱发的脑基底动脉血管舒缩活动与细胞外钙内流及CaCCs作用相关。     

化学药物对家兔离体小肠平滑肌电生理特性的影响

观察各种化学药物对家兔离体小肠各段平滑肌的作用,采用常规离体灌流的十二指肠、空肠及回肠平滑肌标本作舒缩运动实验,记录用药前后各段小肠平滑肌的收缩活动特征及变化规律.结果显示：不同浓度的乙酰胆碱和磷酸组织胺能增强小肠各段平滑肌的收缩频率与幅度,其幅值变化与用药前有显著性差异（P＜0.01） ,并呈剂量依赖性;而不同浓度的肾上腺素和阿托品则抑制小肠各段平滑肌（P＜0.01） .不同肠段对各种化学药物的作用存在着差异,一般十二指肠作用最强,空肠次之,回肠最差.     

微重力对血管及血管内皮细胞的影响

血管系统功能紊乱是微重力诱导立位耐力不良发生的重要因素之一。血管内皮细胞是覆盖在血管内壁上组成血管管腔面的一层单层细胞,是血管壁的重要组成部分,并且在血管功能调控中起到渗透屏障、调节舒缩等重要作用。近年研究发现,微重力可对不同部位的血管系统和血管内皮细胞产生不同的影响,比如可使脑动脉缩血管反应性增加、舒血管反应性下降,颈动脉和腹主动脉缩血管和舒血管反应性下降,肺动脉缩血管反应性下降、舒血管反应性增加,肠系膜动静脉和下肢动脉缩血管反应性下降。另外,微重力可促进大血管来源的内皮细胞生长,但抑制微血管来源的内皮细胞的生长。本文就微重力对血管及血管内皮细胞影响的研究进展作一概述。     

血管内皮生长因子对猪心肌侧枝血管生成的作用

为检测血管内皮生长因子165（VEGF165)能否促进冠状动脉侧枝血管形成,实验在成功制作小型猪慢性心肌缺血模型后,将以复制缺陷复组腺病毒为载体的人VEGF165互补脱氧核糖核酸[(cDNA)Ad-VEGF165]直接注入左回旋支（LCX）分布的缺血心肌内,以心电图门控单光子发射计算机断层摄影和离体太动脉造影检测冠状动脉侧枝形成,心肌灌注和功能变化,结果显示,与对照组和自身给预Ad-VEGF165前比较,给予Ad-VEGF165四周后心肌缺血面积（P＜0．01）和最大缺血程度（P＜0．01）明显减小,左心室射血分数（P＜0．01）TCX区局部心室壁运动（P＜0．05）明显改善,治疗组侧枝血管生成明显多于对照组（P＜0．05）,表明Ad-VEGF165能诱导心肌侧肢血管形成并改善心肌灌注与运动功能。     

姜黄素对慢性低氧高二氧化碳大鼠肺动脉高压及肺动脉管壁胶原的影响

目的：研究姜黄素对慢性低氧高二氧化碳大鼠肺动脉压力及肺动脉管壁Ⅰ型胶原的影响。方法：36只SD大鼠随机分为正常对照组（NC组）,低O2高CO2 4周组（HH组）,低O2高CO2 4周＋姜黄素组（HC组）,采用免疫组化、图像分析等方法观察姜黄素对慢性低O2高CO2大鼠肺动脉压力、肺细小动脉显微和超微结构及肺动脉管壁Ⅰ型胶原的影响。结果：①血流动力学检测显示HH组mPAP明显高于NC组（P〈0．01）,HC组mPAP明显低于HH组（P〈0．01）,三组间mCAP无明显差异（P〉0．05）;②光镜下,肺细小动脉管壁面积／管总面积比值（WA／TA）、肺细小动脉中膜平滑肌细胞核密度（SMC）、肺细小动脉中膜厚度（PAMT）HH组较NC组明显增高（均P〈0．01）,HC组WA／TA、SMC和PAMT较HH组明显降低（均P〈0．01）;③电镜下,HH组肺细小动脉中膜平滑肌细胞增生,面积增大,染色质增多,外膜胶原纤维密集,HC组大鼠肺细小动脉内皮细胞结构基本正常,胶原少见,中膜平滑肌细胞和外膜胶原纤维增生较HH组明显为轻;④免疫组化法发现肺细小动脉Ⅰ型胶原平均吸光度值HH组明显高于Nc组（P〈0．01）,HC组明显低于HH组（P〈0．01）。结论：姜黄素具有降低慢性低O2高CO2性肺动脉高压、改善肺血管重建及抑制肺动脉管壁Ⅰ型胶原沉积的作用。     

血管紧张素—（1—7）对大鼠血管平滑肌细胞PKC和ERK1／2的抑制作用

采用Western blot,氘－胸腺嘧啶（3H－TdR)和氘－亮氨酸（3H－Leu)掺入等技术和方法,用血管紧张素Ⅱ（AngⅡ)和血管紧张素－（1－7）[Ang-(1-7)]刺激大鼠血管平滑肌细胞（VSMCs),观察和分析Ang-(1-7)对VSMCs增殖及蛋白激酶C（PKC）和胞外调节蛋白激酶（ERK）表达的影响,Ang-(1-7)能明显抑制基础和AngⅡ刺激下的VSMCs PKC-Ⅱ和ERK1／2蛋白表达（P＜0．01或P＜0．05）,减少3H－TdR和3H－Leu掺入量（P＜0．01或P＜0．05）,结果提示,Ang-(1-7)对VSMCs增殖有抑制作用,这可能与影响PKC－ζ和ERK1／2蛋白表达有关。     

Biomechanical adaptation of porcine carotid vascular smooth muscle to hypo and hypertension in vitro

Previous research in arterial remodeling in response to changes in blood pressure seldom included both hyper- and hypotension. To compare the effects of low and high pressure on arterial remodeling and vascular smooth muscle tone and performance, we have utilized an in vitro model. Porcine carotid arteries were cultured for 3 days at 30 and 170mmHg and compared to controls cultured at 100mmHg for 1 and 3 days. On the first and last day of culture, pressure-diameter and pressure-wall thickness curves were measured under normal smooth muscle tone using a high-resolution ultrasonic device. Last-day experiments included measurements where vascular smooth muscle was contracted or totally relaxed. From the data wall cross-sectional area, Hudetz elastic modulus and a contraction index related to the diameter reduction under normal smooth muscle tone were calculated. We found that although wall cross-sectional area (indicating wall mass) did not change much, Hudetz elastic modulus was significantly reduced in the 3-day hypotension group. Inspection of the wall contraction index suggests that this is due to a reduction in the vascular smooth muscle tone. Further, the peak of contraction index was found to be shifted to higher pressures in the 3-day 170mmHg group. We conclude that vascular smooth muscle performance adapts to both hypo- and hypertension at short time scales and can alter the biomechanics of the vascular wall in vitro.     

Effects of arterial wall stress on vasomotion

Smooth muscle and endothelial cells in the arterial wall are exposed to mechanical stress. Indeed blood flow induces intraluminal pressure variations and shear stress. An increase in pressure may induce a vessel contraction, a phenomenon known as the myogenic response. Many muscular vessels present vasomotion, i.e., rhythmic diameter oscillations caused by synchronous cytosolic calcium oscillations of the smooth muscle cells. Vasomotion has been shown to be modulated by pressure changes. To get a better understanding of the effect of stress and in particular pressure on vasomotion, we propose a model of a blood vessel describing the calcium dynamics in a coupled population of smooth muscle cells and endothelial cells and the consequent vessel diameter variations. We show that a rise in pressure increases the calcium concentration. This may either induce or abolish vasomotion, or increase its frequency depending on the initial conditions. In our model the myogenic response is less pronounced for large arteries than for small arteries and occurs at higher values of pressure if the wall thickness is increased. Our results are in agreement with experimental observations concerning a broad range of vessels.     

Smooth muscle-specific expression of SV40 large TAg induces SMC proliferation causing adaptive arterial remodeling

To study the effects of enhanced smooth muscle cell (SMC) proliferation on arterial vessel geometry in the absence of vessel trauma, we developed a transgenic mouse model expressing SV40 large T antigen under control of the 2.3-kb smooth muscle-myosin heavy chain promoter. Transgenic mice studied at ages from 3 to 13 wk showed a 3.2-fold increase in arterial wall SMC density, with 28% of SMC exhibiting proliferative cell nuclear antigen staining, confirming enhanced SMC proliferation, which was accompanied by two- to threefold increases in arterial wall areas (P < 0.05). Remarkably, despite increased vessel wall mass, the lumen area was not compromised, but rather was increased. A tightly conserved linear relationship was found between arterial circumference and wall thickness with slopes of 0.036 for both transgenics (r = 0.93, P < 0.01) and controls (r = 0.77, P < 0.01), suggesting the hypothesis that the conservation of wall stress functions as a primary determinant of adaptive arterial remodeling. This establishes a new model of adaptive vessel remodeling occurring in response to a proliferative input in the absence of mechanical injury or primary flow perturbation.     

Remodeling of resistance arteries in organoid culture is modulated by pressure and pressure pulsation and depends on vasomotion

The hypothesis was tested that pressure and pressure pulsation modulate vascular remodeling. Arterioles ( approximately 200 microm lumen diameter) were dissected from rat cremaster muscle and studied in organoid culture. In the first series, arterioles were kept at a stable pressure level of either 50 or 100 mmHg for 3 days. Both groups showed a progressive increase in myogenic tone during the experiment. Arterioles kept at 50 mmHg showed larger endothelium-dependent dilation, compared with vessels kept at 100 mmHg on day 3. Remodeling, as indicated by the reduction in maximally dilated diameter at 100 mmHg, was larger in arterioles kept at 50 mmHg compared with 100 mmHg: 34 +/- 4.5 versus 10 +/- 4.8 microm (P < 0.05). In the second series, arterioles were subjected to a stable pressure of 60 mmHg or oscillating pressure of 60 +/- 10 mmHg (1.5 Hz) for 4 days. Pressure pulsation induced partial dilation and was associated with less remodeling: 34 +/- 4.0 versus 19 +/- 4.5 microm (P < 0.01) for stable pressure versus oscillating pressure. Vasomotion was frequently observed in all groups, and inward remodeling was larger in vessels with vasomotion: 30 +/- 2.5 microm compared with vessels that did not exhibit vasomotion: 8.0 +/- 5.0 microm (P < 0.01). In conclusion, these results indicate that remodeling is not enhanced by high pressure. Pressure pulsation causes partial dilation and reduces inward remodeling. The appearance of vasomotion is associated with enhanced inward remodeling.     

Numerical simulation of pulsatile flow in a compliant curved tube model of a coronary artery

The endothelial cells (ECs) lining a blood vessel wall are exposed to both the wall shear stress (WSS) of blood flow and the circumferential strain (CS) of pulsing artery wall motion. These two forces and their interaction are believed to play a role in determining remodeling of the vessel wall and development of arterial disease (atherosclerosis). This study focused on the WSS and CS dynamic behavior in a compliant model of a coronary artery taking into account the curvature of the bending artery and physiological radial wall motion. A three-dimensional finite element model with transient flow and moving boundaries was set up to simulate pulsatile flow with physiological pressure and flow wave forms characteristic of the coronary arteries. The characteristic coronary artery curvature and flow conditions applied to the simulation were: aspect ratio (lambda) = 10, diameter variation (DV) = 6 percent, mean Reynolds number (Re) = 150, and unsteadiness parameter (alpha) = 3. The results show that mean WSS is about 50 percent lower on the inside wall than the outside wall while WSS oscillation is stronger on the inside wall. The stress phase angle (SPA) between CS and WSS, which characterizes the dynamics of the mechanical force pattern applied to the endothelial cell layer, shows that CS and WSS are more out of phase in the coronaries than in any other region of the circulation (-220 deg on the outside wall, -250 deg on the inside wall). This suggests that in addition to WSS, SPA may play a role in localization of coronary atherosclerosis.     

Adrenergic catecholamine trophic activity contributes to flow-mediated arterial remodeling

Stimulation of alpha1-adrenoceptors (ARs) induces proliferation, hypertrophy, and migration of vascular smooth muscle cells and adventitial fibroblasts in cell and organ culture. In vivo studies have confirmed this direct trophic action and found that endogenous catecholamines contribute to neointimal formation and wall hypertrophy induced by mechanical injury. In murine carotid artery, these effects are mediated by alpha 1B-ARs, whereas alpha 1D-ARs mediate contraction and alpha 1A-ARs are not expressed. Herein, we examined whether catecholamines also contribute to arterial wall growth in a noninjury model, i.e., flow-mediated remodeling. In wild-type mice or mice deficient in norepinephrine and epinephrine synthesis [dopamine beta-hydroxylase knockout (DBH-KO)], all distal branches of the left carotid artery (LC) except the thyroid artery were ligated to reduce flow in the LC and increase flow in the right carotid artery (RC). Twenty-one days later, negative hypertrophic remodeling of the LC [i.e., -20% (decrease) in lumen area, -2% in circumference of the external elastic lamina (CEEL), +98% (increase) in thickness of the intima media, and +71% in thickness for adventitia; P < 0.01 vs. sham ligation] and positive eutrophic remodeling of the RC [+23% in lumen area, +11% in CEEL; P < 0.01 vs. sham ligation] were inhibited in DBH-KO mice [LC: +10% intima media and +3% adventitia; RC: +9% lumen area and +3% CEEL]. This inhibition was associated with reduced proliferation in the RC and reduced apoptosis and leukocyte accumulation in the RC and LC when examined 5 days after ligation. Carotid remodeling in alpha 1D-AR-knockout mice evidenced little or no inhibition, which suggests dependence on alpha 1B-ARs. These findings suggest that catecholamine-induced trophic activity contributes to both flow-mediated negative remodeling and adaptive positive arterial remodeling.     

Changes of opening angle in hypertensive and hypotensive arteries in 3-day organ culture

To study the effect of pressure changes on the opening angle of arteries in organ culture, tubular segments of porcine common carotid arteries were cultured with pulsatile flow perfusion under hypertensive (150+/-20 mmHg), normotensive (100+/-20 mmHg), or hypotensive (30+/-10 mmHg) pressure while maintaining the arteris at a physiological wall shear stress of approximately 15 dyn/cm(2) for up to 3 days. Arteries were then cut into short ring segments by sections perpendicular to the axis and then cut open radially to observe the opening angle in aerated phosphate buffered saline solution (37 degrees C). Norepinephrine (NE, 10 microM), carbacol (CCh, 100 microM), and sodium nitroprusside (SNP, 10 microM) were added after the radial cut at 30, 20, and 30 min intervals, the opening angles were measured, respectively. Results show that hypertensive arteries developed a significantly larger opening angle than normotensive and hypotensive arteries, associated with a significant increase in cell proliferation. In addition, with smooth muscle contraction activated by NE, the opening angle decreases significantly in hypertensive arteries but has little change in hypotensive and normotensive arteries, indicating an enhancement of smooth muscle contraction on the lumen side of the hypertensive arterial wall. In comparison, hypotensive pressure has little effect on arterial opening angle and cell proliferation.     

A new imaging technique to study 3-D plaque and shear stress distribution in human coronary artery bifurcations in vivo

OBJECTIVE: Bifurcations of coronary arteries are predilection sites for atherosclerosis and expansive remodeling, the latter being associated with plaque vulnerability. Both are related to blood flow-induced shear stress (SS). We present a new approach to generate 3-D reconstructions of coronary artery bifurcations in vivo and investigate the relationship between SS, wall thickness (WT) and remodeling. METHODS: The patient specific 3-D reconstruction of the main branch of the bifurcation was obtained by combining intravascular ultrasound and biplane angiography, and the 3-D lumen of the side branch was based on biplane angiography only. The two data sets were fused and computational methods were applied to determine the SS distribution, using patient derived flow and viscosity data. The intravascular ultrasound data allowed us to measure local WT and remodeling in the main branch. RESULTS: The lumen reconstruction procedure was successful and it was shown that the impact of the side branch on SS distribution in the main branch diminished within 3mm. Distal to the bifurcation, two continuous regions in the main branch were identified. In the proximal region, we observed lumen preservation, and expansive remodeling. Although a plaque was observed in the low SS region at the non-divider wall, no relationship between SS and WT was found. In the distal region, we observed lumen narrowing and a significant positive relationship between SS and WT. CONCLUSIONS: A new imaging technique was applied to generate a 3-D reconstruction of a human coronary artery bifurcation in vivo. The observed relationship between SS, WT and remodeling in this specific patient illustrates the spatial heterogeneity of the atherosclerosis in the vicinity of arterial bifurcations.     

Toward functional genomics of flow-induced outward remodeling of resistance arteries

In resistance-sized arteries, a chronic increase in blood flow leads to increases in arterial structural luminal diameter and arterial wall mass. In this review, we summarize recent evidence that outward remodeling of resistance arteries 1) can help maintain and restore tissue perfusion, 2) is not intimately related to flow-induced vasodilatation, 3) involves transient dedifferentiation and turnover of arterial smooth muscle cells, and 4) is preceded by increased expression of matricellular proteins, which have been shown to promote disassembly of focal adhesion sites. Studies of experimental and physiological resistance artery remodeling involving differential gene expression analyses and the use of knockout and transgenic mouse models can help unravel the mechanisms of outward remodeling.