ACE活性和eNOS含量与妊高征相关性研究

目的:探讨胎盘组织一氧化氮合酶含量和血清中血管紧张素转化酶(ACE)活性改变在妊高征发生、发展中的作用。方法:选择轻、中、重度妊高征病人各10例为实验组,正常妊娠妇女30例为对照组,用马尿酸微量比色法检测血清中ACE活性,采用免疫组化ABC法分析妊高征胎盘组织中内皮型一氧化氮合酶(eNOS)含量的变化情况。结果:1妊高征组ACE活性明显高于对照组;2妊高征患者胎盘中eNOS含量显著低于正常足月孕者(P<0.05),且轻度妊高征患者胎盘eNOS含量显著高于中度及重度患者(P<0.05)。结论:血清ACE活性升高与妊高征的发生、发展密切相关。正常足月孕胎盘和妊高征患者胎盘绒毛血管内皮细胞中均存在eNOS抗原,妊高征患者胎盘中含量的减少与其发病有关。     

The effect of puerarin on serum nitric oxide concentration and myocardial eNOS expression in rats with myocardial infarction

Puerarin (1) is a major effective ingredient extracted from the traditional Chinese medicine Ge-gen (Radix Puerariae, RP). Recently, puerarin has been used to treat patients with coronary artery diseases (CAD). However, the mechanisms of puerarin on CAD are still not very clear. In this study, we investigated the role of puerarin on serum nitric oxide (NO) concentration, myocardial endothelial nitric oxide synthase (eNOS) gene expression, the protein expression of eNOS and inducible nitric oxide synthase (iNOS), as well as the level of protein kinase B (Akt/PKB) phosphorylation in rats with myocardial infarction. We found that puerarin (120 mg/kg/day, i.p.) could increase serum nitrite concentration in rat with myocardial ischemia (MI). It also induced the gene expression or activation of eNOS, protein expression of eNOS, and the Akt/PKB phosphorylation. From these results, we suggested that puerarin could increase serum nitric oxide level of rat with myocardial infarction, which should be one of the mechanisms of the therapeutic effect of puerarin on CAD. The increased expression of eNOS and the Akt/PKB pathway may be the underlying mechanism by which puerarin stimulates NO production.     

The effect of puerarin on serum nitric oxide concentration and myocardial eNOS expression in rats with myocardial infarction

Puerarin (1) is a major effective ingredient extracted from the traditional Chinese medicine Ge-gen (Radix Puerariae, RP). Recently, puerarin has been used to treat patients with coronary artery diseases (CAD). However, the mechanisms of puerarin on CAD are still not very clear. In this study, we investigated the role of puerarin on serum nitric oxide (NO) concentration, myocardial endothelial nitric oxide synthase (eNOS) gene expression, the protein expression of eNOS and inducible nitric oxide synthase (iNOS), as well as the level of protein kinase B (Akt/PKB) phosphorylation in rats with myocardial infarction. We found that puerarin (120 mg/kg/day, i.p.) could increase serum nitrite concentration in rat with myocardial ischemia (MI). It also induced the gene expression or activation of eNOS, protein expression of eNOS, and the Akt/PKB phosphorylation. From these results, we suggested that puerarin could increase serum nitric oxide level of rat with myocardial infarction, which should be one of the mechanisms of the therapeutic effect of puerarin on CAD. The increased expression of eNOS and the Akt/PKB pathway may be the underlying mechanism by which puerarin stimulates NO production.     

Homocysteine impaired endothelial function through compromised vascular endothelial growth factor/Akt/endothelial nitric oxide synthase signalling

1. Hyperhomocysteinaemia (HHcy) is associated with endothelial dysfunction and has been recognized as a risk factor of cardiovascular disease. The present study aimed to investigate the effect of homocysteine (Hcy) on endothelial function in vivo and in vitro, and the underlying signalling pathways. 2. The HHcy animal model was established by intragastric administration with l ‐methionine in rats. Plasma Hcy and nitric oxide (NO) concentration were measured by fluorescence immunoassay or nitrate reductase method, respectively. Vasorelaxation in response to acetylcholine and sodium nitroprusside were carried out on aortic rings. Human umbilical vein endothelial cells (HUVEC) were treated with indicated concentrations of Hcy in the in vitro experiments. Intracellular NO level and NO concentration in culture medium were assayed. The alterations of possible signalling proteins were detected by western blot analysis. 3. l ‐methionine administration induced a significant increase in plasma Hcy and decrease in plasma NO. Endothelium‐dependent relaxation of aortic rings in response to acetylcholine was impaired in l ‐methionine‐administrated rats. The in vitro study showed that Hcy reduced both intracellular and culture medium NO levels. Furthermore, Hcy decreased phosphorylation of endothelial nitric oxide synthase (eNOS) at serine‐1177 and phosphorylation of Akt at serine‐473. Hcy‐induced dephosphorylation of eNOS at Ser‐1177 was partially reversed by insulin (Akt activator) and GF109203X (PKC inhibitor). Furthermore, Hcy reduced vascular endothelial growth factor (VEGF) expression in a dose‐dependent manner. 4. In conclusion, Hcy impaired endothelial function through compromised VEGF/Akt/endothelial nitric oxide synthase signalling. These findings will be beneficial for further understanding the role of Hcy in cardiovascular disease.     

芍药苷对缺氧损伤内皮细胞产生NO、eNOS和细胞粘附分子的影响

目的:观察芍药苷对缺氧损伤的人脐静脉内皮细胞(HUVEC)产生一氧化氮(NO)、内皮型一氧化氮合酶(eNOS)和细胞粘附分子(ICAM-1、VCAM-1)的影响。方法:体外培养HUVEC,传至3代后,以不同浓度的芍药苷分别作用于HUVEC,同时进行缺氧处理。以硝酸还原酶法测定培养液上清中的NO,免疫细胞化学法检测内皮细胞eNOS的表达,细胞ELISA法测定细胞表面ICAM-1和VCAM-1的含量。结果:HUVEC在缺氧48h后产生NO的量显著减少(P<0.001),eNOS表达下调,而ICAM-1、VCAM-1表达上调;芍药苷可以剂量依赖性的增加内皮细胞NO生成量,上调eNOS的表达,下调ICAM-1、VCAM-1表达。结论:芍药苷可能通过增加HUVEC eNOS的表达增加NO的释放、抑制ICAM-1及VCAM-1的表达等途径对内皮细胞起保护作用。     

Reversal of SIN-1-induced eNOS dysfunction by the spin trap,DMPO, in bovine aortic endothelial cells via eNOS phosphorylation

Background and Purpose

Nitric oxide (NO) derived from eNOS is mostly responsible for the maintenance of vascular homeostasis and its decreased bioavailability is characteristic of reactive oxygen species (ROS)-induced endothelial dysfunction (ED). Because 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), a commonly used spin trap, can control intracellular nitroso-redox balance by scavenging ROS and donating NO, it was employed as a cardioprotective agent against ED but the mechanism of its protection is still not clear. This study elucidated the mechanism of protection by DMPO against SIN-1-induced oxidative injury to bovine aortic endothelial cells (BAEC).

Experimental Approach

BAEC were treated with SIN-1, as a source of peroxynitrite anion (ONOO⁻), and then incubated with DMPO. Cytotoxicity following SIN-1 alone and cytoprotection by adding DMPO was assessed by MTT assay. Levels of ROS and NO generation from HEK293 cells transfected with wild-type and mutant eNOS cDNAs, tetrahydrobiopterin bioavailability, eNOS activity, eNOS and Akt kinase phosphorylation were measured.

Key Results

Post-treatment of cells with DMPO attenuated SIN-1-mediated cytotoxicity and ROS generation, restoration of NO levels via increased in eNOS activity and phospho-eNOS levels. Treatment with DMPO alone significantly increased NO levels and induced phosphorylation of eNOS Ser¹¹⁷⁹ via Akt kinase. Transfection studies with wild-type and mutant human eNOS confirmed the dual role of eNOS as a producer of superoxide anion (O₂⁻) with SIN-1 treatment, and a producer of NO in the presence of DMPO.

Conclusion and Implications

Post-treatment with DMPO of oxidatively challenged cells reversed eNOS dysfunction and could have pharmacological implications in the treatment of cardiovascular diseases.     

丹皮酚对高脂血清损伤的人内皮细胞的保护作用(英文)

目的观察丹皮酚对高脂血清损伤的人脐静脉内皮细胞(HUVECs)的保护作用,并探讨其作用机制。方法 20%高脂血清作用于HUVECs细胞24 h制备高脂血清损伤模型。丹皮酚组细胞加入20%高脂血清24 h后再分别加入丹皮酚124,247和495μmol.L-1。采用倒置显微镜观察HUVECs形态学变化;MTT法检测细胞存活率;用硝酸还原酶法检测一氧化氮(NO)含量;用RT-PCR法检测内皮型一氧化氮合酶(eNOS)mRNA的表达。结果与正常对照组相比,模型组中大部分细胞出现片状分离和脱落,然而丹皮酚干预后细胞形态趋于正常。丹皮酚能够显著提高细胞存活率(P<0.01)。经丹皮酚124,247和495μmol.L-1干预后,细胞存活率从模型组的(53.0±10.1)%依次升高至(68.4±9.1)%,(84.5±6.7)%,(98.1±7.5)%。丹皮酚能够显著提高NO含量和eNOS mRNA水平(P<0.01)。NO含量从模型组的(54±4)μmol.L-1依次升高至79±6,115±5和(136±6)μmol.L-1;eNOS mRNA的表达水平由模型组的0.215±0.060增加至0.451±0.045,0.563±0.013,0.704±0.068。结论丹皮酚可能通过上调高脂血清损伤人脐静脉内皮细胞eNOS的表达促进NO的合成,从而发挥其对高脂血清损伤内皮细胞的保护作用。     

高糖应激对H9c2细胞凋亡作用

目的 探讨高糖应激早期对H9c2细胞存活的影响及其可能的信号转导通路.方法 高糖培养H9c2细胞24 h后,收集细胞进行细胞活力和凋亡的测定,用Western blot方法 测定蛋白激酶(Akt)的磷酸化水平和内皮细胞一氧化氮合酶(eNOS)的表达.结果 与对照(NG)组相比,高糖培养(HG)组H9c2细胞活力改善,凋亡减少,而P13K抑制剂LY294002预处理和NOS抑制剂L-NAME处理均抑制短期高糖培养对H9c2细胞的保护作用.与NG组相比,HG组早期Akt磷酸化水平升高,eNOS蛋白表达增加,结论 在高糖应激早期(24 h内),高糖通过活化P13K/Akt/eNOS信号通路,改善H9c2细胞的活力,减少其凋亡.     

Targeting sigma-1 receptor with fluvoxamine ameliorates pressure-overload-induced hypertrophy and dysfunctions

Objective: We here investigated the effect of sigma-1 receptor (Sig-1R) stimulation with fluvoxamine on myocardial hypertrophy, cardiac functional recovery and defined mechanisms underlying its cardioprotective action.

Methods: Wistar rats subjected to bilateral ovariectomy (OVX) were treated with abdominal aortic banding between the right and left renal arteries. To confirm the cardioprotective role of Sig-1R stimulation, we treated the rats with Sig-1R agonist (fluvoxamine, 0.5 and 1 mg/kg) orally once a day for 4 weeks after the onset of aortic banding.

Results: Interestingly, the expression of Sig-1R in the left ventricle (LV) decreased significantly 4 weeks after pressure overload (PO)-induced hypertrophy in OVX rats. The fluvoxamine administration significantly attenuated PO-induced myocardial hypertrophy with concomitant increase in the expression of Sig-1R in LV. Fluvoxamine also attenuated hypertrophy-induced impaired LV functions. The cardioprotective effect of fluvoxamine was nullified by treatment with Sig-1R antagonist (NE-100; 1 mg/kg). Fluvoxamine treatment significantly restored PO-induced impaired eNOS and Akt activity in the LV.

Conclusion: We here found, for the first time, the potential role of Sig-1R expression in the heart in attenuating PO-induced hypertrophy in OVX rats. Fluvoxamine treatment protects PO-induced cardiac injury via upregulation of Sig-1R and stimulation of Sig-1R-mediated Akt-eNOS signaling in ovariectomized rats.     

金粉蕨素拮抗氧化损伤所抑制的内皮细胞增殖的作用及其机制

目的　探讨金粉蕨素拮抗Menadione氧化损伤所抑制的内皮细胞增殖的作用及其机制。方法　以Menadione(O- 2 )损伤人脐静脉内皮细胞作为氧化损伤模型 ,采用MTT法和细胞计数法 ,观察不同浓度金粉蕨素对Menadione损伤内皮细胞生长抑制率的影响 ;利用硝酸还原酶法测定培养液中NO含量 ;以Westernblot检测细胞eNOS活性及磷酸化ERK1 / 2的表达。结果　金粉蕨素保护组与损伤组相比 ,内皮细胞的生长抑制率明显降低 ,培养液中NO含量增高 ,eNOS活性增强 ,磷酸化ERK1 / 2表达上调。结论　NO和ERK1 / 2通路可能介导了金粉蕨素拮抗Menadione氧化损伤所抑制内皮细胞增殖的保护作用     

Stimulation of Sigma-1 receptor signaling by dehydroepiandrosterone ameliorates pressure overload-induced hypertrophy and dysfunctions in ovariectomized rats

Objective: Decreased dehydroepiandrosterone (DHEA) levels are associated with endothelial dysfunction and increased cardiovascular mortality in postmenopausal women. We investigated the role of DHEA, also known as sigma-1 receptor (Sig-1R) agonist, in myocardial hypertrophy, cardiac functional recovery and defined mechanisms of cardioprotective action. Methods: Wistar rats subjected to bilateral ovariectomy (OVX) were further treated with abdominal aortic stenosis. DHEA (15 and 30 mg/kg) was administered orally once a day for 14 days starting from 2 weeks after aortic banding. Results: Time course study indicated that left ventricle (LV) weight:body weight (BW) ratio increased time-dependently from 1 to 4 weeks after pressure-overload (PO) with significant inversed regulation of Sig-1R expression. Treatment with the Sig-1R agonist, DHEA, significantly attenuated PO-induced myocardial hypertrophy with increased expression of Sig-1R in the LV. DHEA also attenuated hypertrophy-induced impaired LV end diastolic pressure, LV developed pressure and LV contractility (± dp/dt_max). DHEA treatment significantly restored PO-induced impaired eNOS and Akt activity in the LV. Conclusion: We report, for the first time to our knowledge, the potential role of Sig-1R expression in the heart to attenuate PO-induced hypertrophy in ovariectomized rats. DHEA treatment protects against PO-induced cardiac injury via upregulation of Sig-1R and stimulation of Sig-1R-mediated Akt-eNOS signaling.     

脂联素对人脐静脉内皮细胞保护作用的实验研究

目的体外培养人脐静脉血管内皮细胞（HUVEC）,加入低密度脂蛋白（LDL）建立细胞损伤模型,观察脂联素（APN）对模型细胞结构和功能的影响。方法观察对照组、LDL损伤组、APN预处理组和APN干预组内皮细胞（EC）的形态改变,测定细胞活性,测定细胞培养上清中一氧化氮（NO）、乳酸脱氢酶（LDH）和6-酮前列腺（6-keto-PGF1）的含量变化,测定细胞中一氧化氮合酶（NOS）的含量。结果与正常细胞对照组比较,LDL损伤组的细胞形态明显改变,细胞存活率明显降低,LDH释放明显增高,NO、NOS和6-keto-PGF1合成明显降低（P〈0.01）;而APN预处理组和干预组能明显降低LDH释放,促进NO、NOS和6-keto-PGF1合成（P〈0.01）。结论 APN对EC有一定的保护作用,能拮抗LDL对EC的损伤。     

Effects of resistin on insulin signaling in endothelial cells

The objective of this study was to investigate the effects of resistin on insulin signaling in human umbilical vein endothelial cells (HUVECs). HUVECs were incubated with recombinant human resistin (0–100 ng/mL) for 24 h. Akt and endothelial nitric oxide synthase (eNOS) phosphorylation levels of endothelial cells under basal or insulin stimulated conditions were measured by Western blot. Nitric oxide (NO) production of HUVECs was also detected. The results showed that resistin could significantly inhibit Akt and eNOS phosphorylation and NO production in endothelial cells under insulin stimulated conditions (P < 0.05 vs control). But under basal conditions, treatment with resistin could result in a decrease in eNOS phosphorylation (P < 0.05 vs control) but had no effect on NO production and Akt phosphorylation levels. These findings suggested that resistin exerted an inhibitory effect on NO production by inhibiting insulin signaling and eNOS phosphorylation in endothelial cells.     

内外源性EETs对血管内皮一氧化氮合酶的表达及其在Thr-495位磷酸化的作用

目的　研究细胞色素P4 5 0表氧化酶基因转染和直接加入EETs对内皮细胞eNOS表达及其在Thr 4 95位磷酸化的影响。方法　在原代培养的牛主动脉内皮细胞中 ,分别加入生理浓度的 8,9 EET(1 0 0nmol·L-1 )、1 1 ,1 2 EET(1 0 0nmol·L-1 )、1 4 ,1 5 EET(1 0 0nmol·L-1 )孵育 4h ,或直接用重组腺相关病毒介导的花生四烯酸表氧化酶转染牛主动脉内皮细胞2wk ,以产生内源性EETs ,用Westernblot法检测总eNOS蛋白的表达及eNOSThr 4 95磷酸化的水平 ;此外 ,从大鼠尾静脉注射真核表达质粒pCB6、pCB6 2C1 1OR、pCB6 2J2和pCB6 F87V ,2wk后检测大鼠主动脉总eNOS表达及eNOSThr 4 95磷酸化的水平。结果　与空白和溶媒组比较 ,外源性EETs明显促进内皮细胞总eNOS表达 ,增加eNOSThr 4 95的磷酸化 ,而CYP4 5 0抑制剂 (1 7 ODYA)则可明显降低eNOS表达和eNOSThr 4 95的磷酸化水平 ;与相应的对照组比较 ,体内和体外转染不同的表氧化酶基因均能明显上调内皮细胞eNOS的表达 ,增加eNOSThr 4 95的磷酸化水平。结论　EETs和CYP表氧化酶不仅能明显促进血管内皮细胞总eNOS蛋白的表达 ,而且还通过其翻译后修饰来增加其Thr 4 95位蛋白磷酸化水平     

红霉素对人脐静脉内皮细胞一氧化氮及钙离子水平的影响

目的　探讨红霉素对人脐静脉内皮细胞一氧化氮通路及钙离子的影响。方法　应用一氧化氮及一氧化氮合酶试剂盒测定内皮细胞NO的含量及NOS的活性 ,采用Fura 2负载荧光技术检测胞内游离钙水平。结果　红霉素能明显增加内皮细胞NO的产生和胞内游离钙水平 ,并能明显增强NOS的活性 ,具有浓度和时间效应。结论　红霉素对人脐静脉内皮细胞一氧化氮通路的影响可能通过胞内游离钙而起作用。     

银杏黄酮苷对氧化损伤内皮细胞产生NO、eNOS和ICAM-1的影响

目的观察银杏黄酮苷对氧化损伤的人脐静脉内皮细胞（HUVEC）产生NO、内皮型一氧化氮合酶（eNOS）和人可溶性细胞间黏附分子（ICAM-1）的影响。方法体外培养HUVEC,传至3代后,以不同浓度的银杏黄酮苷分别作用于HUVEC,然后进行氧化损伤处理。以硝酸还原酶法测定培养液上清中的NO水平,免疫细胞化学法检测内皮细胞eNOS的表达,ELISA法测定细胞培养液中ICAM-1的含量。结果HUVEC在氧化损伤（H2O2100μmol/L,2h）后产生NO的量显著减少（P〈0.01）,eNOS表达下调,ICAM-1表达上调;银杏黄酮苷可以剂量依赖性的增加内皮细胞NO生成量,上调eNOS的表达,下调ICAM-1表达。结论银杏黄酮苷可能通过增加HUVEC eNOS的表达增加N0的释放、抑制ICAM-1的表达等机制对内皮细胞起保护作用。     

普伐他汀对人内皮祖细胞一氧化氮合成的影响

目的观察普伐他汀对人内皮祖细胞（EPCs）一氧化氮（NO）合成的影响。方法密度梯度离心法获取外周血单个核细胞,培养7d后,收集贴壁细胞并分别加入普伐他汀,10μmol/L及100μmol/L干预48h,免疫组化、荧光显微镜和流式细胞仪鉴定EPC,用RT-PCR方法测定对细胞内皮型一氧化氮合酶（eNOS）mRNA表达的影响,并用硝酸还原酶法测定培养液中一氧化氮（NO）的水平。结果普伐他汀组的人内皮祖细胞eNOS mRNA的表达、NO的合成明显增加。结论普伐他汀可增加人内皮祖细胞eNOS mRNA的表达和NO的合成     

Endothelium-dependent and -independent relaxation and VASP serines 157/239 phosphorylation by cyclic nucleotide-elevating vasodilators in rat aorta

Endothelium-dependent vasodilation is thought to be mediated primarily by the NO/cGMP signaling pathway whereas cAMP-elevating vasodilators are considered to act independent of the endothelial cell layer. However, recent functional data suggest that cAMP-elevating vasodilators such as beta-receptor agonists, adenosine or forskolin may also be endothelium-dependent. Here we used functional and biochemical assays to analyze endothelium-dependent, cGMP- and cAMP-mediated signaling in rat aorta. Acetylcholine and sodium nitroprusside (SNP) induced a concentration-dependent relaxation of phenylephrine-precontracted aorta. This response was reflected by the phosphorylation of the vasodilator-stimulated phosphoprotein (VASP), a validated substrate of cGMP- and cAMP-dependent protein kinases (cGK, cAK), on Ser(157) and Ser(239). As expected, the effects of acetylcholine were endothelium-dependent. However, relaxation induced by the beta-receptor agonist isoproterenol was also almost completely impaired after endothelial denudation. At the biochemical level, acetylcholine- and isoproterenol-evoked cGK and cAK activation, respectively, as measured by VASP Ser(239) and Ser(157) phosphorylation, was strongly diminished. Furthermore, the effects of isoproterenol were repressed by eNOS inhibition when endothelium was present. We also observed that the relaxing and biochemical effects of forskolin were at least partially endothelium-dependent. We conclude that cAMP-elevating vasodilators, i.e. isoproterenol and to a lesser extent also forskolin, induce vasodilation and concomitant cyclic nucleotide protein kinase activation in the vessel wall in an endothelium-dependent way.