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1.
Objective The present study was undertaden to observe the expression of angiotensin Ⅱ (Ang Ⅱ) type 1 (AT1) and type 2 (AT2) receptors in human hypertrophic scars,and explore their role in the proliferation of fibroblasts in human hypertrophic scars.Methods The expression of both AT1 and AT2 receptors in fibroblasts of hypertrophic scars was detected with immunohistochemical staining.  相似文献   

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ObjectiveTo determine the biotic effects of angiotensin Ⅱ (Ang Ⅱ) on the migration of rat smooth muscle cells (VSMCs) and investigate the mechanisms involved in the development of vascular injury. Methods VSMCs isolated from aortic media of Wistar rats and cultured by the modified explant method were adopted. In the presence and absence of Ang Ⅱ, the expression of Ang Ⅱ receptor (ATR) and reorganization of the actin cytoskeleton and focal adhesion of VSMCs were studied by an immunocytochemistry technique and fluorocytochemistry technique. Migration assays were performed with a modified Boyden’s chamber. The effects of AT(1)R antagonist (CV- 11974), AT2R antagonist (PD123319) on the aforementioned target were studied. Results VSMCs migration was stimulated by adding Ang Ⅱ. The dynamic reorganization of actin cytoskeleton and focal adhesions may be an important mechanism by which Ang Ⅱ facilitates VSMCs motility. The expression of AT(1)R in VSMCs could be upregulated initially after treatment with Ang Ⅱ, then decreased gradually. The expression of AT(1)R was downregulated by AT(1)R antagonists. The effect of Ang Ⅱ on VSMCs migration was mediated by AT(1)R, while AT2R had no significant effect. Conclusions The dynamic reorganization of focal adhesions and the actin cytoskeleton is required for Ang Ⅱ- induced VSMCs migration. This effect is mediated by AT(1)R.  相似文献   

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Objective: To observe the effects of sodium tanshinone ⅡA sulfonate (STS) on angiotensin Ⅱ (Ang Ⅱ)-induced hypertrophy of myocardial cells through the expression of phosphorylated extracellular signal-regulated kinase (p-ERK1/2). Methods: In the primary culture of neonatal rat myocardial cells, the total protein content in myocardial cells was determined by coomassie brilliant blue and the protein synthesis rate was measured by [3H]-Leucine incorporation as indexes for hypertrophy of myocardial cells. The expression of p-ERK1/2 was determined using Western blot and immunofluorescence labeling. Results: (1) The total protein and protein synthesis rate increased significantly in contrast to the control group after the myocardial cells were stimulated by Ang Ⅱ (1 μ mol/L) for 24 h; STS markedly inhibited the increment of the total protein level induced by Ang Ⅱ and the syntheses of protein. (2) After pretreatment of myocardial cells with Ang Ⅱ (1 μmol/L) for 5 min, the p-ERK1/2 protein expression was increased, with the most obvious effect shown at about 10 min; pretreatment of myocardial cells with STS at different doses (2, 10, 50μmol/L) for 30 min resulted in obvious inhibition of the expression of p-ERK1/2 stimulated by Ang Ⅱ in a dose-dependent manner. (3) After the myocardial cells were stimulated by AngⅡ (1 μ mol/L), the immunofluorescence of ERK1/2 rapidly appeared in the nucleus. The activation and translocation process of ERK1/2 induced by Ang Ⅱ was blocked distinctly by STS. (Conclusion: STS inhibited the myocardial cell hypertrophy induced by Ang Ⅱ, and the mechanism may be associated with the inhibition of p-ERK1/2 expression.  相似文献   

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Objective To investigate the mechanism of a novel angiotensin Ⅱ type 1 receptor-associated protein (ATRAP) interfering with angiotensin Ⅱ type 1 (AT1) receptor-mediated vascular smooth muscle cell (VSMC) growth and neointimal formation. Methods VSMCs isolated from thoracic aorta of adult Sprague-Dawley (SD) rats were used in this study. ATRAP cDNA was subcloned into pcDNA3 vector and then transfected into VSMCs. DNA synthesis and extracellular signal-regulated kinase (ERK) and phospho-ERK expressions in VSMCs were assayed by measurement of ^3H thymidine incorporation and Western blotting, respectively. Morphological changes were observed in the balloon injured artery with or without transfection of ATRAP cDNA using 12-week-old male SD rats. Results ATRAP overexpression in VSMCs inhibited angiotensin Ⅱ (Ang Ⅱ)-induced ^3H thymidine incorporation 48 hours after Ang Ⅱ stimulation ( P 〈 0. 05 ). In VSMC, Ang Ⅱ stimulation increased the phosphorylation of ERK, which reached the peak around 60 minutes. The activation of phospho-ERK was significantly decreased by ATRAP ( P 〈 0. 05 ). Neointimal formation was markedly inhibited by ATRAP overexpression in injuried arteries. Conclusions The AT1 receptor-derived activation of ERK plays an essential role in Ang Ⅱ-induced VSMC growth. The growth inhibitory effects of ATRAP might be due to interfering with AT1 receptor-mediated activation of ERK in VSMC growth and neointimal formation.  相似文献   

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Objective: To study the effect of curcumin on fibroblasts in rats with cardiac fibrosis. Methods: The rats were randomly divided into 4 groups(n=12 in each group): the normal control, isoproterenol(ISO), ISO combined with low-dose curcumin(ISO+Cur-L), and ISO combined with high-dose curcumin(ISO+Cur-H) groups. ISO+Cur-L and ISO+Cur-H groups were treated with curcumin(150 or 300 mg·kg-1·day-1) for 28 days. The primary culture of rat cardiac fibroblast was processed by trypsin digestion method in vitro. The 3rd to 5th generation were used for experiment. Western blot method was used to test the expression of collagen type Ⅰ/Ⅲ, α-smooth muscle actin(α-SMA), transforming growth factor(TGF)-β1, matrix metalloproteinase(MMP)-9 and tissue inhibitor of metalloproteinase(TIMP)-1. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetr-azolium bromide(MTT) assay was applied to test the proliferation of fibroblast. Result: Curcumin significantly decreased interstitial and perivascular myocardial collagen deposition and cardiac weight index with reducing protein expression of collagen type Ⅰ/Ⅲ in hearts(P0.05). In addition, curcumin directly inhibited angiotensin(Ang) Ⅱ-induced fibroblast proliferation and collagen type Ⅰ/Ⅲ expression in cardiac fibroblasts(P0.05). Curcumin also inhibited fibrosis by inhibiting myofibroblast differentiation, decreased TGF-β1, MMP-9 and TIMP-1 expression(P0.05) but had no effects on Smad3 in Ang Ⅱ incubated cardiac fibroblasts. Conclusions: Curcumin reduces cardiac fibrosis in rats and Ang Ⅱ-induced fibroblast proliferation by inhibiting myofibroblast differentiation, decreasing collagen synthesis and accelerating collagen degradation through reduction of TGF-β1, MMPs/TIMPs. The present findings also provided novel insights into the role of curcumin as an anti-fibrotic agent for the treatment of cardiac fibrosis.  相似文献   

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Angiotensinogen is a member of the serpin family. It is produced constitutively and released into the circulation mainly by the liver. Angiotensinogen forms angiotensin Ⅰ by action of the circulated renin released from the kidney. Angiotensin Ⅱ (Ang Ⅱ), an octapeptide hormone with sequence Asp-Arg-Val-Tyr-Ile-His-Pro-Phe,is converted from angiotensin Ⅰ through removal of two terminal residues by the angiotensin-converting enzyme (ACE) mostly catalyzed in the lung.1 This peptide binds to two subtype receptors, angiotensin type 1 receptor (AT1R) and angiotensin type 2 receptor (AT2R),members of the superfamily of heptahelical G protein coupled receptors, with different affinities.2 It is well known that AT1R and AT2R crosstalk and lead to counterregulatory functions in many systems, especially the cardiovascular system.3 Accumulating data established the roles of AT1R in the classic actions of Ang Ⅱ including vasoconstriction and cardiovascular hypertrophy, whereas AT2R is suggested to exert direct functions in vasodilation and antigrowth effects.4 Recent publications provide new insights into the roles of AT2R with increasing responsibilities. Recent progresses in AT2R research are reviewed in this article.  相似文献   

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目的观察血管紧张素Ⅱ(AngⅡ)及其受体拮抗剂(AT1RA)对体外培养的肝星状细胞Ⅰ型胶原蛋白合成及其mRNA表达的影响。方法采用HSC-T6肝星状细胞系作为活化的肝星状细胞的研究模型。将培养的肝星状细胞分为对照组、AngⅡ组、AT1RA组和AngⅡ+AT1RA组。采用ELISA法检测细胞培养上清液中Ⅰ型胶原蛋白的含量。RT-PCR法检测肝星状细胞中Ⅰ型胶原mRNA的表达。结果细胞培养上清液中Ⅰ型胶原蛋白含量及肝星状细胞Ⅰ型胶原mRNA的表达水平,AngⅡ组均高于对照组,差异有统计学意义(P<0.05),AT1RA组与AngⅡ+AT1RA组均低于对照组,差异有统计学意义(P<0.05)。结论AngⅡ能够促进肝星状细胞Ⅰ型胶原蛋白的合成及其mRNA的表达,而AT1RA能够明显抑制这一作用。  相似文献   

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目的:观察血管紧张素Ⅱ(angiotensinⅡ,AngⅡ)诱导的正常大鼠肾小球系膜细胞(HBZY-1)血管紧张素Ⅱ1型受体(angiotensinⅡtype 1 receptor,AT1R)蛋白和Ⅳ型胶原(ColⅣ)蛋白的表达情况及氟伐他汀对AT1R和ColⅣ表达的影响,探讨其肾脏保护作用的可能机制。方法:将HBZY-1细胞分为3组:①阴性对照组;②不同浓度(0.1,1.0,10μmol/L)AngⅡ刺激组;③1.0μmol/L AngⅡ加不同浓度(0.1,1.0,10μmol/L)氟伐他汀干预组,蛋白质印迹法检测各组AT1R蛋白的表达,酶联免疫吸附实验(ELISA法)检测各组ColⅣ蛋白的表达。结果:AngⅡ刺激后,HBZY-1细胞AT1R及ColⅣ的表达随AngⅡ浓度增加而增强;氟伐他汀能够剂量依赖性地抑制AT1R和ColⅣ的表达。结论:氟伐他汀能够抑制AngⅡ诱导的HBZY-1细胞AT1R和ColⅣ的表达,同时AT1R和ColⅣ的表达存在正相关,推断氟伐他汀可能通过下调AT1R影响ColⅣ的表达,进而改善高血压肾脏硬化。  相似文献   

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目的 在血管紧张素Ⅱ(angiotensinⅡ,AngⅡ)存在情况下,探讨血管紧张素1-7(angiotensin1-7,Ang1-7)对SD大鼠心室成纤维细胞的影响.方法 采用新生1~3d的SD乳鼠,用胰蛋白酶和Ⅱ型胶原酶消化心室,采用差速贴壁法获取成纤维细胞,将细胞完全随机化分组为对照组(不予处理)、AngⅡ组、Ang1-7组、AngⅡ+Ang1-7组(先用Ang1-7预处理30 min,再加入AngⅡ处理).采用免疫荧光鉴定细胞,CCK-8检测细胞增殖,Western blot检测细胞Rac1、Rad、gp91 phox(Nox2)、P65、结缔组织生长因子(connective tissue growth factor,CTGF)蛋白的表达,实时荧光定量PCR测定Ⅰ型、Ⅲ型胶原蛋白(Col Ⅰ、ColⅢ)和纤维连接蛋白(fibronectin) mRNA的表达.结果 AngⅡ能够促进SD大鼠心室成纤维细胞增殖,Ang1-7能减弱AngⅡ的促增殖作用(P<0.05);与对照组比较,AngⅡ组Rac1、Nox2、P65、CTGF表达增加,Rad表达下降,Col Ⅰ、ColⅢ、fibronectin转录增加(P<0.05);与AngⅡ组比较,AngⅡ+Ang1-7组Rac1、Nox2、P65、CTGF表达减少,Rad表达升高,Col Ⅰ、ColⅢ、fibronectin转录下降(P <0.05);Ang1-7组上述各项指标与对照组比较,差异无统计学意义(P>0.05).结论 AngⅡ存在时,Ang1-7对心室成纤维细胞具有保护作用.Ang1-7通过调节Rac1、Rad及下游蛋白的表达,能够抑制成纤维细胞合成细胞外基质.  相似文献   

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OBJECTIVE: To investigate the effects of angiotensin II (AngII) and AT1a blocker losartan on growth and proliferation of rat hepatic stellate cells (HSCs). METHODS: Rat HSCs were isolated, cultured and identified, followed by incubation with AngII or losartan at different concentrations. The cell growth and proliferation were assessed via cell counting and MTT assay, and the effects of the agents on HSC DNA synthesis evaluated by way of (3)H-thymidine incorporation ((3)H-TDR). RESULTS: AngII (1 x 10(-9) to 1 x 10(-7) mol/L) stimulated HSC proliferation as demonstrated by cell counting, MTT assay and thymidine incorporation test (P < 0.05), but such effect was not observed at lower doses (<1 x 10(-9) mol/L). Losartan had significant inhibitory effect on HSC growth at the concentration of 1 x 10(-8) to 1 x 10(-6) mol/L (P < 0.05), but not at lower doses (<1 x 10(-8) mol/L). Co-stimulation of the cells with losartan and AngII did not result in a significant increase in cell number as compared with the control group (P > 0.05). CONCLUSION: Rapid proliferation of rat HSCs occurs in response to AngII treatment, but is inhibited after AT1a receptor is blocked with the antagonist losartan.  相似文献   

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Objective To investigate the different effects of an angiotensin Ⅱ type 1 (AT(1)) receptor antagonist, losartan, and an angiotensin converting enzyme (ACE) inhibitor, fosinopril, on cardiomyocyte apoptosis, myocardial fibrosis, and angiotensin Ⅱ (AngⅡ) in the left ventricle of spontaneously hypertensive rats (SHRs). Methods SHRs of 16-week-old were randomly divided into 3 groups: SHR-L (treated with losartan, 30 mg·kg(-1)·d(-1)), SHR-F (treated with fosinopril, 10 mg·kg(-1)·d(-1)), and SHR-C (treated with placebo). Each group consisted of 10 rats. Five rats, randomly selected from each group, were killed at the 8th and 16th week after treatment. Cardiomyocyte apoptosis, collagen volume fraction (CVF), perivascular collagen area (PVCA) and AngⅡ concentrations of plasma and myocardium were examined. Results Compared with the controls at the 8th and 16th week, systolic blood pressures were similarly decreased in both treatment groups. Left ventricular weight and left ventricular mass indexes were significantly lower in both treatment groups. However, the latter parameter at the 16th week was reduced to a less extent in the fosinopril group than that in the losartan group. Compared with the controls, cardiomycyte apoptotic index was significantly reduced at the 8th week only in the fosinopril group, and at the 16th week in both treatment groups. The index of the fosinopril group was lower than that of the losartan group at the latter endpoint examined. Compared with the controls, the left ventricular collagen volume fraction and perivascular collagen area at the 8th and 16th weeks were significantly reduced in the SHRs treated with either fosinopril or losartan. However, the collagen volume fraction at the latter endpoint in the fosinopril group was lower than that in the losartan group. Compared with the controls at endpoints, plasma and myocardium Ang Ⅱ levels were significantly increased in the losartan group. However, plasma Ang Ⅱ concentrations were not altered, and myocardium AngⅡ concentrations at the 8th and 16th weeks were significantly reduced in the fosinopril group. Conclusions Both losartan and fosinopril could effectively inhibit cardiomyocyte apoptosis and myocardial fibrosis and reverse heart hypertrophy. Fosinopril may be more effective in these cardioprotective effects, suggesting that the effects of both drugs are related to the inhibition of myocardium renin-angiotension-aldsterone system.  相似文献   

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Background  Angiotensin II (Ang II) acting at angiotensin AT1 receptor (AT1R) has well documented effects on cardiovascular structure such as the promotion of cardiovascular hypertrophy and fibrosis, which are believed to be opposed by angiotensin AT2 receptor (AT2R) stimulation. The expressions of AT1R and AT2R are up-regulated in senescent hearts. The purpose of this study was to investigate the interaction of signal transduction between AT1R and AT2R, and to detect whether there is any difference in the interaction in rat hearts of different age.
Methods  In 3.5-, 12-, 18- and 24-month-old rats, the heart cell membrane activities of protein kinase C (PKC) and tyrosine kinase were measured when AT1R and AT2R were both activated by Ang II or just the AT1R was activated by Ang II and PD123319. The activities of cytosolic phospholipase A2 (cPLA2) and the levels of cGMP were investigated when AT1R and AT2R were both activated by Ang II or just the AT2R was activated by Ang II and losartan. 
Results  When AT1R and AT2R were both activated compared to when the AT1R was activated, the activities of PKC were not different in hearts from 3.5- and 12-month-old rats, but decreased significantly in 18- and 24-month-old rats; the activities of tyrosine kinase were not different in 3.5-month-old rats but decreased significantly in 12-, 18- and 24-month-old rats. The activities of cPLA2 were all decreased significantly in rats of different age when AT1R and AT2R were both activated compared to when the AT2R was activated. Treatment with Ang II alone compared to Ang II and losartan decreased the levels of cGMP (fmol/mg) in rats of different age (102.7±12.7 versus 86.0±8.0 in 3.5-month-old rats, P<0.05; 81.0±9.4 versus 70.0±6.3 in 12-month-old rats, P<0.05; 69.8±5.6 versus 54.2±5.3 in 18-month-old rats, P<0.01; 57.7±8.0 versus 39.0±3.0 in 24-month-old rats, P<0.01).
Conclusions  The activation of AT1R inhibited the signal transduction of AT2R during the aging variation, and the activation of AT2R inhibited the signal transduction of AT1R in rat heart of different age.

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