一氧化氮对肾性高血压大鼠主动脉收缩功能的影响

目的:探讨二肾一夹（2K1C）肾性高血压大鼠主动脉收缩功能的改变及其与一氧化氮的关系。 方法:实验分为假手术组、2K1C组、卡托普利组、NAME组和精氨酸组等5组，利用术后4周的肾性高血压大鼠的胸主动脉进行离体血管环实验，并测定主动脉环一磷酸鸟苷（cGMP）的含量。 结果:2K1C肾性高血压大鼠离体主动脉环对苯肾上腺素、血管紧张素Ⅱ、ACh、KCl的收缩反应显著高于假手术组，主动脉cGMP含量明显少于假手术组。卡托普利可逆转2K1C大鼠的上述改变。L-精氨酸可使上述异常的主动脉收缩功能部分恢复，并增加主动脉cGMP含量。一氧化氮合酶抑制剂L-NAME使主动脉cGMP含量进一步减少，主动脉对缩血管物质的收缩反应无进一步增强。各组大鼠的胸主动脉用L-NAME抑制一氧化氮生成后，对硝普钠的最大舒张反应无明显差别。 结论:2K1C肾性高血压大鼠主动脉收缩功能的改变可能与NO合成、释放减少和缩血管物质产生增多有关。     

肾性高血压大鼠主动脉血红素加氧酶-1表达增加

目的探讨肾性高血压时血红素加氧酶(HO)/一氧化碳(CO)系统的变化,以明确血红素加氧酶在肾性高血压发病过程中的意义及作用。方法①制作两肾一夹(2K1C)肾性高血压大鼠模型,分别于2、4、6、8周记录血压,用放免法测定血浆中血管紧张素II的含量。②分光光度比色法测定主动脉微粒体中HO的活性。③用W estern b lot方法测定主动脉HO-1蛋白的表达。结果从术后2周起,2K1C组血压明显高于假手术组(P<0.01);同时血浆AngII含量显著增加(P<0.01)。2K1C组在4周和6周时主动脉HO活性升高明显(P<0.05),但8周时有所回降,但仍高于对照组;2K1C组4周时HO-1蛋白含量明显升高,比假手术组高25.38%(P<0.05)。结论在肾性高血压大鼠,血浆AngII增高诱导了HO-1的表达增加来对抗压力负荷对血管的损害。     

内源性血管紧张素Ⅱ对大鼠血管钙化的作用

目的:在大鼠血管钙化模型上观察内源性血管紧张素II(AngⅡ)对大鼠血管钙化的影响。方法:用VitD₃皮下注射和尼古丁灌胃诱导大鼠血管钙化模型。测定血管组织中钙含量、[⁴⁵Ca²⁺]聚集及碱性磷酸酶活性作为观察钙化的指标。结果:钙化血管组织中钙含量,[⁴⁵Ca²⁺]摄入及碱性磷酸酶活性分别高于对照组。血管组织中的血管紧张素原mRNA、血浆和血管AngⅡ含量均高于对照组水平。血管紧张素转换酶抑制剂卡托普利和AngⅡ受体AT₁阻断剂洛沙坦处理的大鼠血管内钙含量、[⁴⁵Ca²⁺]聚集及碱性磷酸酶活性显著低于单纯钙化组。卡托普利处理的钙化大鼠血浆和动脉中AngⅡ含量、动脉中血管紧张素原mRNA的含量也显著低于钙化组水平。结论:钙化大鼠血浆和血管组织中AngⅡ水平上调,卡托普利和洛沙坦可减轻大鼠血管钙化程度。     

自发性高血压大鼠主动脉结构重建

本文采用组织形态学方法和计算机图象分析,研究了４－５５周自发性高血压大鼠胸主动脉几何形态及显微结构成分的重建。结果显示：随着血压增高和年龄增长,ＳＨＲ主主显微结构成分的重均比ＷＫＹ大鼠显著,说明压力因素对血管重建起重要作用。ＳＨＲ主 动脉肥厚为研。高血压早期以血管平滑肌细胞肥大和ＶＳＭＣ面积增加为主,高血压老龄期则以胶原纤维积聚为特征。ＶＳＭＣ及细胞外基质的变化构成了ＳＨＲ主动脉重建的重要过程。     

葡萄籽原花青素对肾血管性高血压大鼠血管重塑的影响

目的: 观察葡萄籽原花青素(GSP)对肾血管性高血压(RH)大鼠血管重塑的影响并初步探讨其机制。方法: 采用两肾一夹法建立RH大鼠模型,并设假手术组(对照组,n=7)。术后2周,选取鼠尾动脉收缩压升至130 mmHg以上的大鼠28只为RH大鼠,随机分为4组(n=7):RH模型组、GSP低剂量(50 mg·kg^-1·d^-1)治疗组、GSP高剂量(200 mg·kg^-1·d^-1)治疗组和卡托普利(30 mg·kg^-1·d^-1)阳性对照治疗组。治疗6周后,分别测定各组大鼠尾动脉收缩压、胸主动脉中膜厚度(MT)、管腔内径(LD)及MT/LD;Masson三色法观察各组胸主动脉胶原蛋白的含量;ELISA法测定主动脉中血管紧张素II(AngII)含量;Western blotting 法检测腹主动脉中TNF-α的蛋白表达。结果: 治疗6周后,与对照组相比,RH 模型组大鼠的尾动脉收缩压、MT、MT/LD、主动脉中的胶原含量、AngⅡ 和TNF-α水平均明显升高,而LD则降低;与RH 模型组相比,GSP能显著降低RH大鼠的尾动脉收缩压、主动脉MT、MT/LD,减少大鼠主动脉中胶原和AngⅡ含量,减少TNF-α的蛋白表达,使LD增大。高剂量GSP治疗组的作用尤为显著,与卡托普利治疗组的作用相当。结论: GSP不仅能显著降低RH大鼠尾动脉收缩压,而且对血管重塑有明显的逆转作用,其机制可能与降低主动脉中AngⅡ的含量和TNF-α的蛋白表达有关。     

血管紧张素II通过细胞外信号调节激酶1/2通路调控过氧化氢酶的表达及促进成纤维细胞表型转化*

 目的： 探讨细胞外信号调节激酶1/2(ERK1/2)在高血压大鼠模型动脉外膜血管重塑中的作用。方法: 利用血管紧张素II (Ang II)微泵灌注制备高血压大鼠模型,随机分为未处理组、生理盐水灌注组和Ang II灌注组。分别检测各组大鼠尾动脉收缩压及血管形态学改变;Western blotting技术检测外膜成纤维细胞过氧化氢酶(CAT)蛋白在未处理组、单纯Ang II、ERK1/2抑制剂PD98059和Ang II+PD98059培养下的表达。结果: 大鼠颈动脉HE染色和收缩压结果显示,与未处理组及生理盐水灌注组相比,Ang II组大鼠颈动脉中膜厚度和收缩压明显增加(P<0.01),动脉形态结构有明显改变,并且有显著的病理性血管重塑发生。Western blotting检测结果显示,PD98059作用下CAT比单纯Ang II明显增高(P<0.05),表明ERK1/2信号通路能够恢复Ang II诱导的CAT表达下调。结论: Ang II可能通过ERK1/2信号通路下调血管外膜CAT的表达,进而促进血管细胞表型转化,导致血管病理性重塑发生。     

SM22α抑制大鼠基质重构相关分子的表达及其在血管肥厚中的意义

 目的：探讨平滑肌蛋白22α（smooth muscle protein 22 alpha,SM22α）对大鼠血管肥厚及基质重构相关分子表达的影响。方法：采用SM22α及其突变体的腺病毒表达载体感染大鼠颈总动脉;利用血管紧张素II（angiotensin II,Ang II）微渗泵植入大鼠皮下复制高血压模型;用HE及免疫组化方法分别观察大鼠颈总动脉肥厚及基质重构相关分子在血管壁的表达情况。结果：Ang II显著升高大鼠的血压;颈总动脉过表达SM22α及其非磷酸化突变体S181A后,显著抑制Ang II诱导的血管肥厚,同时伴有MMP-2、MMP-9、 ICAM-1和VCAM-1的表达减少。结论：SM22α及其非磷酸化突变体显著抑制血管肥厚,该过程可能与其抑制基质重构相关的MMP及黏附分子的表达有关。     

Rho蛋白解离抑制因子α在高血压大鼠胸主动脉的表达

目的 研究高血压大鼠胸主动脉以及周期性张应变刺激下血管平滑肌细胞(VSMCs)的Rho蛋白解离抑制因子(RhoGDIα)的表达变化,探讨血管紧张素Ⅱ(AngⅡ)信号通路对其表达的调控影响. 方法 应用实时PCR和Western blotting技术分别检测4周、12周和18周自发性高血压大鼠(SHR, n =4)和正常血压京都种鼠(WKY, n =4)胸主动脉RhoGDIα mRNA和蛋白的表达;免疫组织化学检测RhoGDIα在SHR和WKY胸主动脉的定位;Western blotting技术检测腹主动脉缩窄性高血压大鼠(ACR, n =6)胸主动脉RhoGDIα蛋白的表达;应用细胞应变加载系统对大鼠胸主动脉VSMCs施加1Hz、10%的周期性张应变,在有或无血管紧张素亚型Ⅰ(AT1)受体拮抗剂 L-158809的条件下观察周期性张应变刺激对VSMCs RhoGDIα蛋白表达的影响. 结果 4周与12周SHR和WKY胸主动脉RhoGDIα表达无显著性差异,而在18周组,SHR胸主动脉RhoGDIα表达显著高于WKY.RhoGDIα主要存在于血管中膜VSMCs.2周和4周ACR胸主动脉RhoGDIα表达较正常对照组显著上调,提示在高血压状态下的主动脉RhoGDIα的表达上调.10%周期性张应变加载抑制了VSMCs的RhoGDIα表达,加入ATI受体拮抗剂后RhoGDIα表达显著低于10%周期性张应变加载组. 结论 大鼠高血压时主动脉RhoGDIα表达上调;Ang Ⅱ信号通路在RhoGDIα表达调控中起重要作用.     

Gαq/11介导的信号转导通路在自发性高血压大鼠主动脉中的变化

目的:观察自发性高血压大鼠(SHR)主动脉Gαq/11及磷脂酶C(PLC)的动态变化,探讨其在SHR高血压发病机制中的意义.方法: 4周龄和12周龄SHR,颈动脉插管记录动脉血压,放免法测定血浆血管紧张素Ⅱ的浓度,免疫印迹法检测主动脉组织Gαq/11和PLC的含量.结果:SHR 12周龄时动脉血压明显增高.4周龄SHR主动脉Gαq/11的表达较对照高69.2%(P＜0.05).4周龄和12周龄SHR主动脉PLCβ3分别较各自同龄对照组高66.9%和85.1%(P＜0.05). 结论: Gαq/11介导的信号转导通路上调参与SHR高血压的发生和发展.     

地塞米松抑制肾素-血管紧张素系统减轻大鼠急性肺损伤

目的：观察肾素-血管紧张素系统（RAS）在大鼠急性肺损伤中的作用及地塞米松（DEX）的影响。方法: 在大鼠失血性休克的基础上,腹腔注射内毒素（二次打击）造成急性肺损伤模型,直接插管法检测大鼠平均动脉血压（MAP）;逆转录聚合酶链式反应(RT-PCR)观察各组大鼠肺脏组织中血管紧张素转换酶（ACE）、血管紧张素原（AGT）、血管紧张素II 1型受体（AT1）和血管紧张素II 2型受体（AT2）mRNA的表达及测定大鼠血清血管紧张素I (AngⅠ)、血管紧张素II（AngⅡ）的变化。结果: 二次打击组（HL）大鼠平均动脉血压恢复很慢,而地塞米松治疗组（HLD）平均动脉血压恢复的速度较HL明显增快,且平均动脉血压水平的升高具有明显差异。与对照组（C）相比,HL组ACE、AGT mRNA表达水平明显增高,而HLD组明显低于HL组。AT1、AT2 mRNA各组表达水平则无明显差异。与C组相比,HL组AngⅡ的含量明显升高,HLD组大鼠血清AngⅡ的含量比HL组均明显减低,Ang I含量的变化不明显。结论: 失血性休克后LPS诱发的急性肺损伤可能与激活肺脏的肾素－血管紧张素系统有关,抑制肺脏的肾素－血管紧张素系统的激活是DEX轻这种急性肺损伤的机制之一。     

半边莲生物碱缓解肾性高血压大鼠的血管重塑

目的： 探讨半边莲生物碱对肾性高血压大鼠主动脉血管重塑的影响。方法: 制备两肾一夹（2K1C）肾性高血压大鼠模型，灌服半边莲生物碱或卡托普利8周，用放射免疫技术测定血浆肾素活性（plasma rennin activity, PRA）。用Weigert法染色并测量腹主动脉中膜厚度及中膜截面积等血管重塑形态学参数。分别用Masson 三色法和免疫组化方法测腹主动脉总胶原蛋白含量和Ⅰ型胶原蛋白含量。结果: 高血压大鼠与假手术组相比PRA明显升高(P<0.05),使用半边莲生物碱后PRA显著降低(P<0.05);卡托普利对PRA无明显影响。高血压大鼠中膜厚度、中膜厚度/ 血管内径、中膜面积和腹主动脉胶原含量与假手术组相比明显升高(P<0.05)；半边莲和卡托普利均可使高血压组大鼠上述指标显著降低(P<0.05)。 结论: 肾性高血压大鼠存在血管重塑现象,半边莲生物碱能抑制胶原的表达、降低肾素活性,对缓解血管重塑有一定作用。     

Immunohistochemical Evidence of Loss of PTEN Expression in Primary Ductal Adenocarcinomas of the Breast

Germline mutations in PTEN, encoding a dual-specificity phosphatase on 10q23.3, cause Cowden syndrome (CS), which is characterized by a high risk of breast and thyroid cancers. Loss of heterozygosity of 10q22-24 markers and somatic PTEN mutations have been found to a greater or lesser extent in a variety of sporadic component and noncomponent cancers of CS. Among several series of sporadic breast carcinomas, the frequency of loss of flanking markers around PTEN is approximately 30 to 40%, and the somatic intragenic PTEN mutation frequency is <5%. In this study, we analyzed PTEN expression in 33 sporadic primary breast carcinoma samples using immunohistochemistry and correlated this to structural studies at the molecular level. Normal mammary tissue had a distinctive pattern of expression: myoepithelial cells uniformly showed strong PTEN expression. The PTEN protein level in mammary epithelial cells was variable. Ductal hyperplasia with and without atypia exhibited higher PTEN protein levels than normal mammary epithelial cells. Among the 33 carcinoma samples, 5 (15%) were immunohistochemically PTEN-negative; 6 (18%) had reduced staining, and the rest were PTEN-positive. In the PTEN-positive tumors as well as in normal epithelium, the protein was localized in the cytoplasm and in the nucleus (or nuclear membrane). Among the immunostain negative group, all had hemizygous PTEN deletion but no structural alteration of the remaining allele. Thus, in these cases, an epigenetic phenomenon such as hypermethylation, -ecreased protein synthesis or increased protein degradation may be involved. In the cases with reduced staining, 5 of 6 had hemizygous PTEN deletion and 1 did not have any structural abnormality. Finally, clinicopathological features were analyzed against PTEN protein expression. Three of the 5 PTEN immunostain-negative carcinomas were also both estrogen and progesterone receptor-negative, whereas only 5 of 22 of the PTEN-positive group were double receptor-negative. The significance of this last observation requires further study.     

Effect of captopril in L-NAME-induced hypertension on the rat myocardium, aorta, brain and kidney

Long-term administration of NG-nitro-L-arginine methyl ester (L-NAME) induces development of hypertension and hypertrophy of the left ventricle in rats. The aim of the present study was to demonstrate the effect of chronic L-NAME treatment on DNA and RNA concentration, and protein synthesis in the rat heart, aorta, brain and kidney and to determine the effect of angiotensin converting enzyme (ACE) inhibitor captopril on these potential alterations. Four groups of rats were investigated: control, L-NAME (40 mg kg-1 day-1), captopril (100 mg kg-1 day-1), and L-NAME (40 mg kg-1 day-1) + captopril (100 mg kg-1 day-1). NO synthase activity in the heart, aorta, brain and kidney was found to be decreased in the L-NAME group. In the group of rats treated with L-NAME + captopril, captopril did not affect NO synthase inhibition. Captopril, however, completely prevented development of hypertension and left ventricular hypertrophy in this group. In the L-NAME group, DNA and RNA concentrations, as well as [14C]leucine incorporation, were significantly increased in all the tissues investigated. In the L-NAME + captopril group, captopril completely prevented the enhancement of DNA and RNA concentrations and [14C]leucine incorporation in all tissues compared to the L-NAME group. Moreover, a significant decrease in RNA concentration and [14C]leucine incorporation below control values was found in the captopril group as well as the L-NAME + captopril group in all the tissues investigated. We conclude that captopril prevented the development of hypertension and increase in nucleic acid concentration and protein synthesis in the heart, aorta, brain and kidney in rats treated with L-NAME + captopril. However, this protective effect of captopril was not associated with increased NO synthase activity in this model of hypertension.     

卡托普利对高血压心脏钙调蛋白磷酸酶与核因子κB p65蛋白表达的影响

 目的：探讨卡托普利对高血压大鼠心脏钙调蛋白磷酸酶（calcineurin）、核因子κBp65（NFκBp65）蛋白表达影响及其机制。 方法：建立腹主动脉缩窄高血压大鼠模型，术后1周用卡托普利治疗，连续10周。以尾动脉测压法观察血压变化，用免疫组织化学和形态计量学方法，观察calcineurin 、NF-κBp65在心脏表达和心脏系数的变化。 结果：经卡托普利治疗，高血压大鼠血压降低（mmHg，P<0.01），心脏系数显著减小（g/100 g，P<0.01），心脏calcineurin和NF-κBp65蛋白高表达下调，阳性表达面积和面积百分比缩小（μm²，P<0.01，或P<0.01）。 结论：卡托普利能通过调控信号转导通路calcineurin-NFAT- NF-κBp65关键蛋白表达，逆转高血压心血管重构。     

不同年龄高血压大鼠血管平滑肌中ERK和MKP-1的表达

目的：研究不同年龄的自发性高血压大鼠（SHR）和Wistar Kyoto大鼠（WKY）主动脉平滑肌中丝裂原活化蛋白激酶（MAPK）及其磷酸酶（MKP-1）的表达及其与高血压的关系。 方法： 用tail-cuff测量大鼠尾动脉血压；分别用Western blotting法和RT-PCR法半定量测定血管平滑肌中磷酸化细胞外信号调节激酶（p-ERK）和MKP-1的蛋白表达以及MKP-1 mRNA的含量。 结果： （1）SHR的血压自8周龄起明显高于WKY（P<0.01），且随年龄增长而升高（P<0.05）至14周以后趋于稳定；（2）SHR主动脉平滑肌中的p-ERK表达明显高于同年龄的WKY（P<0.01），随年龄增长而递增（P<0.05），与血压呈正相关；（3）SHR主动脉平滑肌中MKP-1蛋白明显高于同龄WKY，而mRNA的表达在5周龄时明显高于WKY，之后均随年龄的增长而递减（P<0.05），与血压和ERK呈负相关，而WKY下降不明显。 结论： MKP-1在高血压的发生和发展过程中起重要作用，其表达逐渐下降可能是导致ERK激活增加，从而导致血管平滑肌细胞增殖、血压升高的重要原因。     

Vascular area with marked resistance elevation in one-clip, two-kidney renovascular hypertensive rats

Blood flow in the terminal aorta or superior mesenteric artery was recorded in conscious one-clip, two-kidney renovascular hypertensive rats and normal control rats with a chronically implanted electromagnetic flow probe. An indwelling catheter for direct measurement of arterial pressure was inserted into the terminal aorta in rats with a flow probe around the superior mesenteric artery. In the hindquarter area supplied by the terminal aorta, the elevation of vascular resistance in hypertensive rats in relation to normal rats was close to the average over the whole body. However, it was about 40% more intense than the average in the superior mesenteric area. Quantitatively, the hindquarter and superior mesenteric beds in hypertensive rats contributed about a quarter and a third of the decrease in total vascular conductance, respectively. Plots of superior mesenteric flow per body weight against arterial pressure at rest for 51 measurements in 9 hypertensive rats revealed an inverse relation between these two variables. These findings indicate that elevation of vascular resistance in the superior mesenteric area and probably the splanchnic area in general play an important role in one-clip, two-kidney renovascular hypertension.     

Regional blood flow in conscious spontaneously hypertensive rats

In spontaneously hypertensive and normal control rats in the conscious state, blood flow was observed in the carotid artery, superior mesenteric artery, renal artery, and terminal aorta with a chronically implanted electromagnetic flow probe. At rest, flow per body weight was not different between the two groups except at the terminal aorta where it was significantly smaller in hypertensive rats (P less than 0.05). Regional peripheral resistance was higher in hypertensive rats than in normal rats in all the four arteries, but its elevation in the former was not uniform but most marked in the hindquarter area supplied by the terminal aorta. Quantitatively, this area was estimated to contribute about 40% of the total conductance decrease in hypertensive rats in comparison with the control. This suggests the importance of elevation of resistance in muscle blood vessels in hypertension. The contributions from the superior mesenteric area and the bilateral kidneys were estimated to be about 15% each. In the transposition response induced by transposing rats from their home cage to a new cage, the increase in hindquarter flow was significantly greater in hypertensive rats than in normal rats (P less than 0.01). The sum of the mean flows of the four arteries, a measure of cardiac output, was not different between hypertensive and normal rats at rest but greater in the former during transposition response. Elevation of arterial pressure in the response in hypertensive rats but not in the normal rats was ascribable largely to a greater increase in cardiac output in the former than the latter.     

Studies of the renal component of the hypertension in rats with aortic constriction. Role of angiotensin II

The object of this study was to investigate the renal component of hypertension in aortic constriction. In 40-day-old Sprague-Dawley rats the aorta were constricted either proximal (PAC) or distal (DAC) to the renal arteries. The rats were examined 3 weeks later together with control rats. The arterial pressure proximal to the constriction was elevated in the PAC group but not in the DAC group. In PAC rats the arterial pressure was also elevated distal to the constriction. There was a significant pressure gradient across the constriction in both PAC and DAC rats. The PAC rats had a significant decrease of renal blood flow, a significant increase in renal vascular resistance and a numerical but not significant decrease of glomerular filtration rate. Serum levels of angiotensin II were not significantly different in PAC and control rats. The pressor effect of a bolus dose of angiotensin II was significantly increased in PAC rats. Captopril, a converting enzyme inhibitor, decreased the arterial pressures and renal vascular resistance in PAC rats. The pressure elevating effects of angiotensin II and pressure lowering effect of captopril were more pronounced distal than proximal to the constriction. We conclude that the kidneys play a major role in the development of hypertension in PAC, and that the local effect of angiotensin II on the renal vascular bed is an important contributor to the renal component of the hypertension.