依那普利对自发性高血压大鼠心肌ACE和ACE2表达的影响

 目的 观察自发性高血压大鼠(spontaneously hypertensive rats, SHR)心肌的血管紧张素转换酶(angiotensin-converting enzyme, ACE)和ACE2的表达,以及依那普利干预的影响。方法 将15只SHR随机分为2组：SHR对照组(n=7)和依那普利组(n=8),分别给以安慰剂、依那普利15mg.kg-1.d-1灌胃干预4周。干预结束后处死大鼠,分离左心室,行RT-PCR、western blot蛋白质免疫印迹检测。同步取10只WKY大鼠作为正常血压对照组。结果SHR心肌的ACE的mRNA和蛋白质的表达都显著高于)WKY组(1.68±0.34 vs 0.33±0.12, P＜0.05;1.21±0.14 vs 0.71±0.11, P＜0.05),而ACE2 的mRNA和蛋白质表达皆明显低于WKY组(0.50±0.15 vs 1.16±0.24, P＜0.05; 0.71±0.24 vs 1.22±0.14, P＜0.05)。依那普利明显降低ACE的mRNA和蛋白质表达(0.44±0.19 vs 1.68±0.34, P＜0.01; 0.87±0.13 vs 1.21±0.14, P＜0.05),提升ACE2的mRNA表达(1.77±0.49 vs 0.50±0.15, P＜0.05),对ACE2的蛋白表达无明显影响(0.42±0.22 vs 0.71±0.24, P＞0.05)。结论 SHR心肌ACE明显升高,ACE2显著降低,有利于血压上调。依那普利能降低ACE,提升ACE2,可能是血管紧张素转换酶抑制剂(angiotensin-converting enzyme inhibitors, ACEI)的降压机制之一。     

小鼠止血带休克后肾组织ACE/ACE2表达变化及意义

目的: 通过观察小鼠止血带休克(TS)后,不同时点血管紧张素转换酶(ACE)和血管紧张素转换酶2(ACE2)在肾脏的表达变化与肾损伤程度的关系,探讨ACE/ACE2表达失衡在TS后肾损伤中的作用。方法: 复制小鼠TS模型,Western blotting测肢体缺血再灌注后12 h内肾组织ACE和ACE2蛋白的表达;利用化学比色方法测定血清和肾组织丙二醛(MDA)含量和超氧化物歧化酶(SOD)活性;制作肾病理切片,观察肾组织形态变化,并利用免疫组织化学方法观察ACE和ACE2的表达部位。结果: Western blotting结果显示,各时点与对照组比较,TS后ACE表达升高,ACE2表达降低;与对照组比较血清和肾MDA水平增高(P<0.05),SOD活性降低(P<0.05);HE病理切片显示,TS后各时点肾组织有充血、炎细胞浸润等不同程度损伤;免疫组化结果显示,ACE在肾小管上皮细胞胞浆表达,TS后表达明显增强;ACE2主要在肾小管上皮细胞管腔膜表达,TS后表达明显降低。结论: TS后肾组织ACE表达升高,ACE2表达降低,ACE/ACE2表达失衡可能与肾损伤有关。     

ACE2及其特殊功能

血管紧张素转换酶2(angiotensin-converting enzyme 2,ACE2)是新发现的与血管紧张素转换酶(ACE)相关的羧肽酶,在肾素-血管紧张素系统(rennin-angiotensin system,RAS)中ACE2可以使AngⅡ转换为Ang1-7,从而产生与血管紧张素Ⅱ相反的效应,同时ACE2还可使AngⅠ转换为Ang1-9 .研究发现:ACE2与高血压、SARS以及肾脏、生殖等系统的疾病有着密切的关系.     

心力衰竭患者心肌组织ACE2表达与心功能的关系

目的观察心力衰竭(简称心衰)患者不同心功能状态下血管紧张素转换酶2(ACE2)基因和蛋白表达变化,探讨其与心衰患者心功能的关系。方法通过手术取材,采用RT-PCR和W estern B lot技术检测30例瓣膜病所致不同程度心衰患者和5例正常人心肌组织中ACE2 mRNA和蛋白表达。结果瓣膜病所致心衰患者心肌组织ACE2 mRNA和蛋白表达均较正常组明显升高(P<0.01),其中中重度心衰患者升高尤为显著(P<0.01)。结论心衰患者心肌组织ACE2基因和蛋白表达明显增强,这可能是心脏的代偿机制,促进ANG II降解,增加ANG1-7合成,保护残存的心功能。     

人血白蛋白对近端肾小管上皮细胞ACE2表达的影响

目的： 研究人血白蛋白对人近端肾小管上皮细胞（HK-2）血管紧张素转换酶2（ACE2）及血管紧张素转换酶（ACE）表达的影响，探讨白蛋白对肾脏损害的机制。方法: 不同浓度人血白蛋白（0、1、5、10、15 g/L）分别加入到培养的人近端肾小管上皮细胞培养48 h，用RT-PCR法和Western blotting法分别检测HK-2细胞ACE2和ACE mRNA和蛋白表达。结果: 正常培养状态下HK-2细胞（空白对照组）存在ACE2 mRNA和蛋白表达，加入不同浓度（5-15 g/L）的人血白蛋白剂量依赖抑制HK-2细胞ACE2 mRNA和蛋白表达（P<0.01）。正常培养状态下HK-2细胞ACE mRNA和蛋白表达水平较低，随着加入白蛋白浓度的增加其表达水平逐渐升高，10 g/L白蛋白显著促进了HK-2细胞ACE mRNA和蛋白表达（P<0.05）。结论: 在体外培养的HK-2细胞存在ACE及ACE2 mRNA和蛋白表达，人血白蛋白可抑制其ACE2表达而促进ACE表达,这可能是白蛋白促肾小管间质损伤及肾小球硬化、间质纤维化的机制之一。     

脑内ACE2基因过表达对高血压前期大鼠血压进展和氧化应激的影响

目的:观察下丘脑室旁核内血管紧张素转换酶2(angiotension-converting enzyme 2,ACE2)基因过表达对高血压前期大鼠血压进展和中枢氧化应激的影响,并探讨ACE2基因中枢降压的分子机制.方法:ACE2基因以慢病毒为载体,载体上携带增强型绿色荧光蛋白(enhanced green fluore...     

ACE/ACE2在AGT-REN双转基因高血压小鼠肾组织的表达变化及意义

目的: 观察血管紧张素原(AGT)-肾素(REN)双转基因高血压小鼠肾脏组织病理改变及血管紧张素转化酶(ACE)/血管紧张素转化酶2(ACE2)的表达变化,探讨ACE和ACE2在高血压肾损伤中的作用。方法: 实验分为4组,随机选择10月龄野生型、AGT转基因、REN转基因以及AGT-REN双转基因雄性C57小鼠各6只。每组动物颈动脉插管检测平均动脉压(MAP),1 h后处死小鼠;左侧肾脏置于10%中性甲醛固定,常规HE染色方法观察肾脏组织病理改变,免疫组化法观察肾脏ACE及ACE2的表达变化;右侧肾脏取出后放入蛋白裂解液中,提取蛋白,进行Western blotting实验,观察肾组织中ACE和ACE2蛋白表达。结果: 与野生型小鼠相比,AGT转基因小鼠MAP无明显变化(P>0.05),REN转基因小鼠MAP降低约15 mmHg(P<0.05);AGT-REN双转基因小鼠MAP明显升高约30 mmHg(P<0.05)。与野生型小鼠相比,AGT转基因和REN转基因小鼠肾组织未见明显病理改变,AGT-REN双转基因小鼠肾组织可见肾小动脉内膜及管壁显著增厚、管腔狭窄、纤维素样坏死、玻璃样变等典型恶性高血压肾损伤病理改变。免疫组化结果显示,与野生型小鼠相比,AGT转基因和REN转基因小鼠肾组织ACE和ACE2表达无明显差异(P>0.05),AGT-REN双转基因鼠肾组织ACE表达明显增高(P<0.05),而ACE2表达明显降低(P<0.05)。Western blotting结果显示:与野生型小鼠相比,AGT转基因鼠肾组织ACE和ACE2表达无明显变化;REN转基因鼠肾组织ACE表达无明显变化,ACE2表达稍降低(P<0.05);双转基因鼠肾组织ACE蛋白表达明显增强, ACE2蛋白表达水平显著降低,ACE/ACE2表达显著失衡。结论: AGT-REN双转基因可致小鼠恶性高血压,导致肾脏严重损伤;ACE/ACE2的表达失衡与血压改变密切相关,降低ACE或提高ACE2的表达可能对防治高血压具有重要意义。     

缺氧与复氧对培养的肺动脉内皮细胞功能的影响

缺氧与复氧均可引起肺血管收缩和损伤，本研究观察肺血管内皮细胞活力和血管紧张素转换酶（ＡＣＥ）释放在其中的作用。培养的新生小牛肺动脉内皮细胞（ＰＡＥＣ）在缺氧条件下（０％Ｏ２－９５％Ｎ２）培养６～２４ｈ，其上清液ＡＣＥ活性无显著变化，而细胞活力于缺氧１２～２４ｈ显著增加（与常氧组相比增加２０％～３３％，Ｐ＜０．０５）。ＰＡＥＣ在缺氧条件下培养２４ｈ，复氧培养３～６ｈ后其上清液ＡＣＥ活性显著增加（与常氧组和缺氧组相比Ｐ＜０．０１），于１２ｈ恢复至复氧前的水平。细胞活力的变化与ＡＣＥ的变化类似，复氧３～６ｈ显著高于常氧水平（Ｐ＜０．０１与常氧组相比），１２ｈ恢复至正常。上述结果表明ＰＡＥＣ的ＡＣＥ和细胞活力的变化可能对肺动脉壁本身ＲＡＳ功能的调节及缺氧性肺血管收缩的发生起一定作用。     

血清ACE2水平在冠心病发生发展中的变化

目的:通过检测血清血管紧张素转换酶2(ACE2)水平,分析ACE2与冠心病(CHD)不同病程之间的相关性,探讨其在CHD发生发展中的变化规律。方法:选取非CHD对照组样本85例,CHD样本174例,并按照冠状动脉狭窄严重程度分成轻度(50%)狭窄组(ls-CHD组)、中度(50%~75%)狭窄组(ms-CHD组)和严重(≥75%)狭窄组(ss-CHD组)。通过ELISA检测所有样本血清中ACE2水平,统计分析CHD不同病程下的ACE2水平,从而探讨血清ACE2水平与CHD发生发展间的关系。结果:ls-CHD、ms-CHD和ss-CHD组血清ACE2水平均高于非CHD组,并且随着冠状动脉狭窄严重程度的加深而上升。男性血清ACE2水平要比女性的高。单一性别内,ls-CHD、ms-CHD和ss-CHD组血清ACE2水平均高于非CHD组,并有显著性差异。回归分析发现性别、糖尿病、CHD与血清ACE2水平相关,并且性别和CHD是血清ACE2水平的独立影响因素。结论:男性血清ACE2水平高于女性;与非CHD患者相比,CHD患者血清ACE2水平升高;在CHD发生发展过程中,血清ACE2水平随CHD病情的恶化而持续升高。     

ACE2在高血压大鼠左心室重构中的作用及缬沙坦干预的作用

目的观察血管紧张素转换酶2(ACE2)在自发性高血压大鼠(SHR)左心室中的表达以及缬沙坦干预后对ACE2表达水平的影响。方法 24只12周龄雄性SHR随机分为SHR组、缬沙坦组,12只同龄雄性血压正常的Wistar大鼠作为正常对照组。10周后处死,测定心脏重量指数(HWI)、左心室重量指数(LVWI);酶联免疫法测定血浆中AngⅡ的浓度;碱水解法测定心肌中羟脯氨酸的含量;反转录-聚合酶链反应检测心肌中ACE2的表达。结果与正常对照组比较,SHR组LVWI、血浆中AngⅡ的浓度以及心肌羟脯氨酸的含量均增高(P<0.05),心肌组织中ACE2的表达显著降低(P<0.05);与SHR组比较,缬沙坦组LVWI、血浆中AngⅡ的浓度以及心肌羟脯氨酸的含量均降低(P<0.05),心肌组织中ACE2表达显著增高(P<0.05)。结论缬沙坦可逆转高血压左心室重构,机制可能与增加心肌中ACE2的表达有关。     

ACE2内源性激动剂DIZE对糖尿病肾病大鼠的保护作用

目的:观察血管紧张素转换酶2(ACE2)内源性激动剂乙酰甘氨酸重氮氨苯脒(DIZE)对糖尿病肾病(DN)大鼠的保护作用。方法:30只Wistar大鼠随机分为正常对照组(NC组)、DN组和DIZE处理组(DIZE组)。DN组与DIZE组一次性腹腔注射链脲佐菌素(65 mg/kg)建立糖尿病模型,12周后糖尿病肾病大鼠模型建立后给予DIZE 15 mg·kg~(-1)·d~(-1)或等量生理盐水皮下注射4周处理。16周末称量体重和肾重,计算肾质量体质量比(KW/BW),收集血、尿标本,检测血糖(GLU)、24 h尿蛋白(24UP)及血清肌酐(SCr)等指标。通过PAS染色观察各组肾脏病理变化;ELISA法检测大鼠AngⅡ、Ang-(1-7)、TGF-β1及VCAM-1水平的变化;通过免疫组化观察collagenⅠ和FN蛋白表达的变化;利用实时荧光定量PCR(RT-qPCR)技术检测大鼠肾组织collagenⅠ和FN mRNA含量的变化;Western blot观察各组大鼠ACE2蛋白表达的变化。结果:DIZE显著提高了糖尿病大鼠ACE2的表达(P0.05),降低了糖尿病大鼠血浆AngⅡ含量(P0.05),提高了Ang-(1-7)的水平(P0.05)。与NC组大鼠相比,DN组与DIZE组大鼠的24UP、SCr和KW/BW明显升高(P0.05),collagenⅠ和FN mRNA水平及蛋白表达量增加,肾脏组织TGF-β1及VCAM-1明显上升(P0.05)。DIZE组与DN组大鼠相比,24UP和SCr水平降低(P0.05),GLU和KW/BW无明显差异,collagenⅠ和FN mRNA含量及蛋白表达量减少,肾脏组织TGF-β1及VCAM-1水平降低(P0.05)。结论:ACE2内源性激动剂DIZE显著提高了ACE2的活性,增加了Ang-(1-7)的含量,从而降低了肾脏纤维化及炎症水平,并对糖尿病肾病大鼠起到保护性作用。     

Hemoglobinemia in mice exposed to high altitude

Male and female mice were exposed to a simulated altitude of 5,500m for 10, 30 or 90 days. After exposure to altitude for 90 days one group of each sex was then returned to sea level pressures for 10 days. In addition to the expected increases in hematocrit and hemoglobin, altitude exposure increased the 2,3-DPG content of red cells. Maximum values of 2,3-DPG (moles/g hemoglobin) occurred after 10 days at altitude and thereafter declined to values comparable to those in sea level mice despite continued exposure to hypoxia.As previously described for rats, mice also exhibit an altitude-induced hemoglobinemia which occurs in the face of a polycythemia. Plasma hemoglobin concentrations were at a steady state after about 30 days at altitude. Both sexes also showed a significant splenic hypertrophy, a bilirubinemia and a hemoglobinuria as a result of altitude exposure. As assessed in male mice a significant induction of heme oxygenase activity occurred in the kidneys but not in the spleen or liver. The latter finding contrasts with results previously observed in rats where induction of heme oxygenase occurs in the liver desplte a decrease in the liver/body weight ratio.Sex differences in the response to hypoxia previously observed with rats also occur in mice. The altitude-induced rise in hematocrit but not hemoglobin appears to be more pronounced in males as was the failure to gain weight. Perhaps both male mice and rats are more severely compromised by altitude than are females of the same speciesThe time course of the hemoglobinemia and its reversal at sea level paralleled the changes in hemoglobin and hematocrit suggesting that it was correlated with the demand on hematopoietic effort. Perhaps the hemoglobinemia is secondary to ineffective hematopoiesis.     

新型冠状病毒受体ACE2在多种疾病中的作用

自2019冠状病毒病(coronavirus disease 2019, COVID-19)暴发以来,血管紧张素转换酶2(angio?tensin-converting enzyme 2,ACE2)作为新型冠状病毒(severe acute respiratory syndrome coronavirus 2, SAR...     

Coronary blood flow in rats native to simulated high altitude and in rats exposed to it later in life

Summary In rats exposed to a simulated high altitude of 3500 m for their whole prenatal and postnatal life a severe cardiac hypertrophy develops. In rats born and first staying 5 weeks at sea level and then being exposed to simulated high altitude, only a unilateral right cardiac hypertrophy occurs. In both groups nutritional coronary blood flow was estimated in left ventricle, right ventricle, and septum and was compared with control animals of similar age. Coronary blood flow was measured at hypoxia in all groups. At first cardiac output was determined by the Fick principle, then⁸⁶Rb was applied and the animals were killed after 55 sec. Activity of⁸⁶Rb was measured in both cardiac ventricles and septum and the fractional uptake was calculated. According to Sapirstein (1956, 1958) the distribution of⁸⁶Rb follows the distribution of cardiac output and from both these data the nutritional blood flow to the parts of the heart may be estimated.Cardiac output was similar in rats exposed to simulated high altitude later in life (newcomers) and in control animals, but it was significantly lower in rats born in the low pressure chamber (natives).Fractions of cardiac output supplying cardiac ventricles and septum in rats from both hypoxic groups were significantly higher than in control animals. In the natives they were significantly higher than in the newcomers. The fractions of cardiac output in both newcomers and natives remained significantly higher than those of the control animals, also when calculated per gram of heart tissue.Nutritional coronary blood flow (in ml/min) was higher in both ventricles and septum of the newcomers and in the right ventricle of the natives, and lower in the septum of the natives, when compared with control animals. Coronary blood flow per gram of heart tissue (in ml/min·g) was significantly higher in all cardiac parts of the newcomers, but it was about the same in all cardiac parts of the natives when compared with controls.The importance of observed changes concerning myocardial tissue oxygenation is analyzed by using Krogh's cylindrical tissue model.Presented in part at the XXVIth International Congress of Physiological Sciences, New Delhi, India, October 20–26, 1974.     

Hypoxic pulmonary steady-state diffusing capacity for CO and alveolar-arterial O2 pressure differences in growing rats after adaptation to a simulated altitude of 3500 m

Summary Steady-state pulmonary diffusing capacity for CO and alveolar-arterial O₂ pressure differences were measured at hypoxia in growing rats adapted to a simulated altitude of 3500 m. The pulmonary diffusing capacity was significantly higher and the alveolar-arterial gradients were significantly lower in the adapted animals as compared with the controls exposed to hypoxia for the first time. The increased diffusing capacity could be explained entirely by the increase of blood O₂ and CO capacity whereas the decrease of gradients might be explained by the increase of blood O₂ capacity together with an increase of the arterio-venous O₂ difference.     

Pre-adaptation,adaptation and de-adaptation to high altitude in humans: cardio-ventilatory and haematological changes

The aim of this study was first to investigate cardio-ventilatory and haematological responses induced by intermittent acclimation and second to study de-adaptation from high altitude observed after descent. To achieve these objectives nine subjects were submitted to intermittent acclimation in a low barometric chamber (8 h daily for 5 days, day 1 at 4500 m, day 5 at 8500 m) before an expedition to the Himalayas. Cardio-ventilatory changes were measured during a hypobaric poikilocapnic hypoxic test (4500 m, barometric pressure = 589 hPa) and haematological changes were studied at sea level. These measurements were performed before and after acclimation, after return to sea level, but also 1 and 2 months after the expedition. In addition, partial pressures of oxygen and carbon dioxide in arterial blood (P _aO₂, P _aCO₂) and arterial erythropoietin concentration [EPO] were measured at rest during the hypoxic test. Results suggested the pre-adaptation protocol was efficient since an increased P _aO₂ (+12%, P < 0.05), a smaller difference in alveolo-arterial P0₂ ( –63%, P < 0.05) and a lower P _aCO₂ ( –11%, P < 0.05), subsequent to ventilatory changes, were observed after acclimation with a significant increase in reticulocytes and in sea level [EPO] (+44% and +62% respectively, P < 0.05). Deadaptation was characterized by a loss of these cardioventilatory changes 1 month after descent, whereas the haematological changes (increased red blood cells and packed cell volume, P < 0.05) persisted for 1 month before disappearing 2 months after descent. This study would also suggest that acute hypoxia performed after a sojourn at high altitude could induce significantly depressed EPO responses (P < 0.05).     

模拟急进高原过程对清醒和麻醉状态大鼠血压和呼吸的影响

目的:为了全面地反映急进高原过程中机体的一些真实改变,本实验通过动态监测清醒和麻醉2种不同状态下大鼠血流动力学指标,旨在探讨清醒和麻醉状态大鼠在急性缺氧时血流动力学的差异,并以此进一步探讨其可能的机制。方法:实验将SD大鼠随机分为麻醉组、清醒组、5 000 m麻醉对照(A-5000-control)组、5 000m麻醉氨基胍(A-5000-AG)组、5 000 m清醒对照(C-5000-control)组和5 000 m清醒氨基胍(C-5000-AG)组。麻醉组和清醒组大鼠在低压氧舱从2 260 m开始,以2 m/s模拟急进高原5 000 m过程;其余4组均在模拟5 000 m海拔条件下进行。实验期间通过Power Lab生理记录仪实时、动态地监测整个过程中大鼠的系统动脉压(system arterial pressure,Psa)、中心静脉压(central venous pressure,CVP)、心率(heart rate,HR)和呼吸频率(breathing rate,BR)。结果:清醒组大鼠的HR和BR明显高于麻醉组,但MAP明显低于麻醉组。随着海拔的逐渐升高,清醒组和麻醉组大鼠均出现平均动脉压(mean arterial pressure,MAP)降低,且清醒组大鼠降低更为显著。另外,在5 000 m时,清醒组大鼠HR明显降低,而整个过程中2组大鼠的BR均无明显改变。静脉注射诱导型一氧化氮合酶(inducible nitric oxide synthase,i NOS)抑制剂氨基胍后,C-5000-AG组和A-5000-AG组大鼠动脉血压均明显升高,而HR和BR未见明显变化。结论:在急进高原过程中,血压和心率会明显下降,而呼吸频率变化不大。该现象可能的机制为:急性缺氧早期机体启动自我保护机制,活化i NOS,大量产生并释放NO,使血管舒张,可调节肺通气、引起血压下降;达到海拔5 000 m左右甚至更早时,机体可能出现失代偿,使心率减慢,引起血压进一步降低。由于受麻醉药物戊巴比妥钠的影响,麻醉状态的大鼠血压下降出现得较为迟缓,而清醒大鼠对急进高原性低氧反应迅速,能够更真实全面地反映急进高原过程中低氧引起的血流动力学改变。