氯沙坦对血管紧张素Ⅱ致培养的牛脑微血管内皮细胞损伤的保护作用

目的：观察氯沙坦对血管紧张素Ⅱ（AngⅡ）致牛脑微血管内皮细胞（BCMECs）损伤的保护作用。方法：用分光光度计测定培养的BCMECs乳酸脱氢酶（LDH）的漏出量，流式细胞仪测定BCMECs细胞间粘附分子－1（ICAM－1）的表达量，硝酸还原酶法和放射免疫分析法分别测定BCMECs上清液中一氧化氮（NO）和内皮素－1（ET1）的含量。结果：AngⅡ呈剂量依赖性增加BCMECsLDH漏出、NO和ET1释放及ICAM－1表达，氯沙坦对此均有明显抑制作用。结论：氯沙坦抑制 AngⅡ致体外培养BCMECs的损伤。     

血管紧张素Ⅱ诱导培养的牛脑微血管内皮细胞凋亡及其机制

目的　研究AngⅡ对牛脑微血管内皮细胞(BCMEC)有无诱导凋亡的作用。方法　利用流式细胞仪和透射电子显微镜检测体外培养的BCMEC凋亡。结果　流式细胞术显示AngⅡ (0 .0 1～ 10 μmol·L- 1)呈浓度依赖性诱导BCMEC凋亡。 10 μmol·L- 1AngⅡ诱导的BCMEC凋亡不能被 10 0 μmol·L- 1AT1受体拮抗剂氯沙坦所抑制 ,而能被 15 0kU·L- 1超氧化物歧化酶所部分抑制。BCMEC经 10 μmol·L- 1AngⅡ刺激 18h后 ,呈现胞浆浓缩、染色质凝集、核碎裂和凋亡小体形成等凋亡的超微结构变化。结论AngⅡ能诱导BCMEC凋亡 ,其机制可能与其刺激BCMEC产生的氧自由基有关。AngⅡ诱导脑血管内皮细胞凋亡可能是其参与脑血管疾病的机制之一     

血管紧张素-(1-7)对血管紧张素II致人脐静脉内皮细胞损伤的保护作用研究

目的 :观察血管紧张素 (1 7) [Ang (1 7) ]对血管紧张素II(AngII)致人脐静脉内皮细胞 (HU VECs)损伤的保护作用。方法 :体外培养的HUVECs随机分为 4组 :对照组 ,AngII组 ,Ang (1 7)组 ,AngII Ang (1 7)组。采用分光光度计测定培养的HU VECs乳酸脱氢酶 (LDH)漏出 ;流式细胞仪检测细胞凋亡 ;硝酸还原酶法和放射免疫分析技术分别测定HUVECs上清液中一氧化氮 (NO)和内皮素 1(ET 1)的含量。结果 :与对照组比较 ,AngII(0 .1μmol·L-1)显著增加HUVECsLDH漏出 (P <0 .0 1)、ET 1分泌(P <0 .0 1)和HUVECs凋亡率 (P <0 .0 1) ,显著减少NO的含量 (P <0 .0 5 ) ;Ang (1 7)呈剂量依赖性抑制了AngII的促LDH漏出、ET 1分泌、增加细胞凋亡等作用 ,同时明显促进HUVECs的NO释放 ;单用Ang (1 7)对HUVECs无明显影响。结论 :Ang (1 7)可抑制AngII所致的体外培养HUVECs损伤 ,对内皮细胞具有保护作用。     

水蛭素对凝血酶所致脑微血管内皮细胞损伤的保护作用

目的探讨凝血酶对体外培养的原代大鼠脑微血管内皮细胞(BMVEC)的损伤作用及凝血酶抑制剂水蛭素的保护作用。方法分离新生大鼠脑组织微血管段,原代培养BMVEC并鉴定。四唑盐(MTT)比色法检测不同浓度凝血酶及水蛭素处理后BMVEC生长抑制状况,并用TUNEL法、透射电镜、核DNA琼脂糖凝胶电泳等3种方法检测BMVEC凋亡。结果原代培养细胞经鉴定为BMVEC。150、300 U.mL-1凝血酶可明显抑制BMVEC生长并诱导BMVEC凋亡,这种作用可被水蛭素阻断。结论病理状态下异常增加的凝血酶可导致BMVEC及血脑屏障损伤。水蛭素对凝血酶所致的BMVEC损伤有明显的阻断作用。     

羟乙基葛根素对过氧化氢致牛脑微血管内皮细胞损伤的保护作用

目的研究牛脑微血管内皮细胞(BCMEC)过氧化损伤机制并探讨羟乙基葛根素对牛脑微血管内皮细胞损伤的保护作用。方法用MTT法和LDH活性检测测定BCMEC的损伤；倒置相差显微镜下一般形态学观察、透射电子显微镜超微结构观察及流式细胞术测定BCMEC凋亡变化。结果H₂O₂ (200 μmol·L^-1)损伤BCMEC后，细胞存活率下降，LDH释放增加，羟乙基葛根素和edaravone可减轻此损伤。H₂O₂ (100 μmol·L^-1)可诱导BCMEC凋亡，羟乙基葛根素 和edaravone对此有保护作用。结论羟乙基葛根素和edaravone对H₂O₂导致的BCMEC坏死和凋亡有保护作用，该作用与其抗氧化作用有关。     

化合物EXP-2528对Ang II诱导大鼠脑微血管内皮细胞表达E-selectin和VCAM-1的影响

本研究利用体外培养大鼠脑微血管内皮细胞(brain microvascular endothelial cells，BMEC)模型，探讨了血管紧张素(Ang)II对大鼠脑微血管内皮细胞表达E-selectin和VCAM-1的影响及其机制，并评价了新型AT₁受体拮抗剂化合物EXP-2528对其的影响。采用RT-PCR和Western blotting分别检测大鼠脑微血管内皮细胞E-选择素(E-selectin)和血管细粘黏附分子-1(vascular cell adhesion molecule-1，VCAM-1)的mRNA及蛋白的表达。结果显示1×10^-7 mol·L^-1 Ang II分别孵育4 h和18 h可显著促进BMEC E-selectin及VCAM-1的mRNA及蛋白的表达，应用氯沙坦和新型选择性AT₁受体拮抗剂化合物EXP-2528选择性阻断AT₁受体对此有明显抑制作用。同时阻断AT₁受体和AT₂受体也可明显抑制Ang II诱导的E-selectin及VCAM-1表达的增加，但是与单独阻断AT₁受体相比无明显差异。而选择性阻断AT₂受体对Ang II诱导的E-selectin及VCAM-1的表达无明显影响。以上实验结果提示，Ang II可通过激动AT₁受体上调BMEC E-selectin和VCAM-1的表达，参与脑血管疾病的发生发展。     

血管紧张素-(1-7)对血管紧张素Ⅱ致人脐静脉内皮细胞损伤的保护作用研究

目的观察血管紧张素-(1-7) [Ang-(1-7)]对血管紧张素II(Ang II)致人脐静脉内皮细胞(HUVECs)损伤的保护作用.方法体外培养的HUVECs随机分为4组对照组,AngII组,Ang-(1-7)组,AngII+Ang-(1-7)组.采用分光光度计测定培养的HUVECs乳酸脱氢酶(LDH)漏出;流式细胞仪检测细胞凋亡;硝酸还原酶法和放射免疫分析技术分别测定HUVECs上清液中一氧化氮(NO)和内皮素-1(ET-1)的含量.结果与对照组比较,Ang II(0.1 μmol·L-1)显著增加HUVECs LDH漏出(P＜0.01)、ET-1分泌(P＜0.01)和HUVECs凋亡率(P＜0.01),显著减少NO的含量(P<0.05);Ang-(1-7)呈剂量依赖性抑制了Ang II的促LDH漏出、ET-1分泌、增加细胞凋亡等作用,同时明显促进HUVECs的 NO释放;单用Ang-(1-7)对HUVECs无明显影响.结论 Ang-(1-7)可抑制Ang II所致的体外培养HUVECs损伤,对内皮细胞具有保护作用.     

依那普利对2型糖尿病大鼠血浆Ang II水平及血管、肾脏AT1受体表达的影响

目的研究依那普利对2型糖尿病大鼠血浆Ang II和AT₁受体表达的影响。方法用放射免疫法测定血浆Ang II水平，免疫组化法观察血管和肾脏AT₁受体表达。结果糖尿病大鼠血浆Ang II明显高于对照组，应用依那普利后大鼠血浆Ang II明显降低。免疫组化染色发现糖尿病大鼠血管内皮细胞、平滑肌细胞和肾脏AT₁受体表达明显增加，依那普利治疗组大鼠血管内皮细胞、平滑肌细胞和肾脏AT₁受体表达与正常组接近。结论糖尿病大鼠血浆Ang II升高，血管和肾脏AT₁受体表达增加，依那普利可降低糖尿病大鼠血浆Ang II水平，下调血管和肾脏AT₁受体表达。     

血管紧张素Ⅱ和缬沙坦对血管内皮细胞AT1/AT2及eNOS表达的调节作用

目的：研究缬沙坦在血管内皮细胞中对血管紧张素Ⅱ(AngⅡ)受体Ⅰ型(AT1)和Ⅱ型(AT2)、一氧化氮合酶(eNOS)的表达和一氧化氮(NO)生成的影响。方法：使用人脐静脉内皮细胞系ECV-304(HUVECs)，分为对照组、AngⅡ组、缬沙坦组和AngⅡ加缬沙坦组，作用不同时间，检测AT1／AT2的mRNA和蛋白表达、eNOS的蛋白表达和NO的生成。结果：在HUVECs细胞中未检测到AT2的蛋白表达，AngⅡ、缬沙坦均显著抑制细胞中AT1的mRNA和蛋白表达，且缬沙坦呈明显的剂量依赖效应，AngⅡ作用36h显著抑制NO的生成而合用缬沙坦可明显逆转该效应。结论：在HUVECs中缬沙坦可通过自身的结合下调AT1，并能逆转AngⅡ长时间作用对NO生成的抑制作用，提示缬沙坦可改善血管内皮细胞的功能。     

Effect of adrenotensin on cell proliferation is mediated by angiotensin II in cultured rat mesangial cells

Aim： Both adrenomedullin （ADM） and adrenotensin （ADT） are derived from the same propeptide precursor, and both act as circulating hormones and local paracrine mediators with multiple biological activities. Compared with ADM, little is known about how ADT achieves its functions. In the present study, we investigated the effect of ADT on cell proliferation and transforming growth factor-β（TGF-β） secretion in cultured renal mesangial cells （MCs） and determined whether angiotensin II （Ang II） was involved in mediating this process. Methods： Cell proliferation was measured by bromodeoxyuridine （BrdU） incorporation assay, Ang II levels were assayed using an enzyme immunoassay, and real time PCR was used to measure Ang II type 1 （AT1） receptor, Ang II type 2 （AT2） receptor, angiotensinogen （AGT）, renin, angiotensin converting enzyme （ACE） and TGF-β1 mRNA levels. TGF-β1 and collagen type IV protein levels in cell media were measured using enzyme-linked immunoassays. Results： ADT treatment induced cell proliferation in a concentration-dependent manner; it also increased the levels of TGF-β1 mRNA and protein as well as collagen type IV excretion by cultured MCs. ADT treatment increased renin and AGT mRNAs as well as Ang II protein, but did not affect the ACE mRNA level. ADT up-regulated angiotensin AT1 receptor mRNA, but not that of the AT2 receptor. The angiotensin AT1 receptor antagonist Iosartan blocked the effects of ADT-induced cell proliferation, TGF-β1 and collagen type IV synthesis and secretion. Conclusion： ADT has a stimulating role in cell proliferation in cultured MCs. Increases in the levels of Ang II and the AT1 receptor after ADT treatment mediate the stimulating effects of ADT on cell proliferation and extracellular matrix synthesis and secretion.     

Protective effects of diltiazem against vascular endothelial cell injury induced by angiotensin‐II and hypoxia

To provide pharmacological data for future clinical studies, this study investigated the protective effects of diltiazem on vascular endothelial cell (VEC) injury induced by angiotensin‐II (AngII), hypoxia, and a combination of both treatments. The concentration of intracellular free calcium and the mitochondrial membrane potential in VEC were assessed as indicators of cell injury. An in vivo hypoxic animal model was used to test the protective effect of diltiazem on vascular endothelial tissues. Our study showed that AngII and hypoxia decreased the mitochondrial membrane potential in VEC, which was significantly inhibited by diltiazem. Diltiazem protected against VEC injury induced by the increased concentration of intracellular free calcium, which was associated with AngII and hypoxia. Diltiazem reduced the apoptosis of rat VEC under a sustained hypoxic condition. In addition, it reduced AngII and endothelin I levels in rat vascular endothelial tissues. Our study confirmed that AngII and hypoxia induced VEC injury by regulating the levels of mitochondrial membrane potential and intracellular free calcium. Diltiazem, a calcium channel blocker, protected VEC from AngII‐ and hypoxia‐induced injury.     

甘肃黄芪黄酮对AngⅡ致内皮细胞凋亡的保护作用

目的探讨甘肃黄芪黄酮化合物芒柄花素与毛蕊异黄酮-7-O-β-D-吡喃葡萄糖对血管紧张素Ⅱ(AngⅡ)诱导人脐静脉内皮细胞(HUVECs)凋亡的影响。方法将不同浓度上述两种黄酮单体(0.01、0.1、1.0、10mg.L-1)分别与AngⅡ(10-6mol.L-1)和HUVECs作用24h后,MTT比色法检测细胞存活率,Hoechst33258荧光染色法观察细胞核形态变化,流式细胞仪及激光共聚焦仪检测细胞凋亡,并观察凋亡基因Fas表达的变化。结果甘肃黄芪黄酮化合物芒柄花素与毛蕊异黄酮-7-O-β-D-吡喃葡萄糖呈剂量依赖性地抑制AngⅡ引起的细胞存活率下降(P<0.05),AngⅡ(10-6mol.L-1)孵育24h后,内皮细胞凋亡率明显多于对照组(P<0.01);芒柄花素(1.0mg.L-1)与毛蕊异黄酮-7-O-β-D-吡喃葡萄糖(1.0mg.L-1)可抑制AngⅡ(10-6mol.L-1)诱导的内皮细胞凋亡(P<0.01),并减少Fas的表达(P<0.05);以上实验芒柄花素与毛蕊异黄酮-7-O-β-D-吡喃葡萄糖两化合物间比较无差异(P>0.05)。结论甘肃黄芪黄酮化合物可减轻AngⅡ诱导的HUVECs凋亡,其机制之一可能与其降低Fas的表达有关。     

Inhibition of the renin-angiotensin system and cardio-renal protection: focus on losartan and angiotensin receptor blockade

Angiotensin II plays a central role in the pathogenesis and progression of proteinuric nephropathies and related cardiovascular complications. Losartan is a selective non-peptide angiotensin Type 1-receptor blocker (ARB) with unique uricosuric effect, not shared by other ARBs. Losartan has demonstrated renoprotective effects in animals and humans with diabetic and non-diabetic renal diseases similar to those of angiotensin-converting enzyme inhibitors, with a lower incidence of dry cough and angioneurotic oedema. A reduced incidence of cerebrovascular events and diabetes has been reported in hypertensive patients with left ventricular hypertrophy on losartan therapy compared with patients treated with atenolol. Whether ARBs have superior cardioprotective effects, compared with other blood pressure medications, is still unknown. Combined angiotensin-converting enzyme inhibitor and ARB therapy improves renal outcomes in non-diabetic nephropathies more than single drug renin-angiotensin system inhibition. Whether this also applies to diabetic nephropathy and related cardiovascular outcomes is still unknown.     

Effects of the angiotensin II receptor blocker losartan on the monocyte expression of biglycan in hypertensive patients

1. Recently, we demonstrated that biglycan (BGN) is increased in circulating monocyte cells from hypertensive patients and that angiotensin (Ang) II is able to increase BGN expression. The present study was designed to investigate the effects of treatment with the angiotensin AT₁ receptor antagonist losartan on monocyte BGN mRNA and protein expression in essential hypertension. 2. One hundred and twenty‐six newly diagnosed hypertensive patients without additional risk factors for atherosclerosis and cardiovascular disease were treated with 100 mg losartan once daily for 6 months. Biglycan mRNA and protein expression was determined in monocytes isolated from peripheral blood before (T₀) and after (T₁) therapy. Plasma levels of interleukin (IL)‐6, tumour necrosis factor (TNF)‐α and high sensitivity C‐reactive protein (hs‐CRP) were also determined. In addition, BGN mRNA and protein expression was determined after the ex vivo addition of 1 μmol/L AngII to monocytes isolated from 20 randomly selected hypertensive patients. 3. Biglycan mRNA and protein expression, blood pressure and plasma levels of fibrinogen, IL‐6, TNF‐α and CRP were significantly lower at T₁ than at T₀. Variations in BGN expression were associated with inflammatory markers, but not directly with blood pressure. In AngII‐stimulated monocytes, BGN mRNA and protein expression was significantly lower at T₁ that at T₀. Moreover, mean BGN mRNA expression in AngII‐stimulated monocytes isolated from losartan‐treated patients was similar to baseline expression in unstimulated monocytes from untreated patients. 4. The results of the present study show that losartan can reduce BGN expression in monocytes from hypertensive patients, without any linear association with blood pressure, suggesting that the effects of AngII on BGN expression in monocytes may be modulated, in part, by an AT₁ receptor blocker.     

氯沙坦对血管紧张素Ⅱ诱导的心肌细胞核酸、蛋白质及c-fos基因表达抑制作用的研究

目的　观察氯沙坦（ｌｏｓａｒｔａｎ,ＬＴ）对血管紧张素Ⅱ诱导的心肌细胞核酸、蛋白质及ｃ ｆｏｓ基因表达的抑制作用。方法　应用培养乳鼠心肌细胞,观察血管紧张素Ⅱ亚型受体拮抗剂 ＬＴ对血管紧张素Ⅱ（ＡｎｇⅡ）诱导的心肌细胞肥大的抑制作用。结果　ＬＴ２×１０－６ｍｏｌ·Ｌ－１能明显抑制ＡｎｇⅡ对心肌细胞核酸及蛋白质合成的促进作用及ｃ ｆｏｓｍＲＮＡ表达。结论　心肌细胞膜表面的ＡＴ受体亚型介导了ＡｎｇⅡ促心肌细胞肥大作用。ｃ ｆｏｓ基因激活是ＡｎｇⅡ诱导心肌细胞肥大的重要机制之一。ＬＴ从受体水平阻断了ＡｎｇⅡ的作用,此类药物应是更具选择性的肾素 血管紧张素系统拮抗剂。     

Regulation of angiotensin-(1-7) and angiotensin II type 1 receptor by telmisartan and losartan in adriamycin-induced rat heart failure

Aim:

To investigate the possible effects of telmisartan and losartan on cardiac function in adriamycin (ADR)-induced heart failure in rats, and to explore the changes in plasma level of angiotensin-(1–7)[Ang-(1–7)] and myocardial expression of angiotensin II type 1/2 receptors (AT1R / AT2R) and Mas receptor caused by the two drugs.

Methods:

Male Sprague-Dawley rats were randomly divided into 4 groups: the control group, ADR-treated heart failure group (ADR-HF), telmisartan plus ADR-treated group (Tel+ADR) and losartan plus ADR-treated group (Los+ADR). ADR was administrated (2.5 mg/kg, ip, 6 times in 2 weeks). The rats in the Tel+ADR and Los+ADR groups were treated orally with telmisartan (10 mg/kg daily po) and losartan (30 mg/kg daily), respectively, for 6 weeks. The plasma level of Ang-(1–7) was determined using ELISA. The mRNA and protein expression of myocardial Mas receptor, AT₁R and AT₂R were measured using RT-PCR and Western blotting, respectively.

Results:

ADR significantly reduced the plasma level of Ang-(1–7) and the expression of myocardial Mas receptor and myocardial AT₂R, while significantly increased the expression of myocardial AT1R. Treatment with telmisartan and losartan effectively increased the plasma level of Ang-(1–7) and suppressed myocardial AT1R expression, but did not influence the expression of Mas receptor and AT₂R.

Conclusion:

The protective effects of telmisartan and losartan in ADR-induced heart failure may be partially due to regulation of circulating Ang-(1–7) and myocardial AT1R expression.