L-精氨酸增加心肌急性缺血大鼠心脏eNOS基因表达

目的　观察大鼠心梗时心脏内皮型一氧化氮合酶 (eNOS)基因表达的变化和L 精氨酸 (L Arg)对大鼠eNOS基因表达的影响。方法　 4 8只健康成年SD大鼠随机分为对照组 (假手术组 )、缺血组两组。分别取 1h、2h、2 4h三个不同时间点。采用开胸结扎冠状动脉左前降支的方法建立心肌缺血模型 ,用逆转录聚合酶链式反应 (RT PCR)检测大鼠心梗后不同时间及L 精氨酸 (30mg/ (kg·次 )× 3)给药后缺血心肌eNOSmRNA表达。结果　①冠脉结扎后 2h组 ,缺血组大鼠心肌eNOSmRNA表达下降 (P <0 0 5 ) ,其下降持续至结扎后 2 4h ;梗死后 2 4h组eNOSmRNA表达与结扎后 2h组相比无显著性差异 ,P >0 0 5 ;②与生理盐水组相比 ,30mg/ (kg·次 )× 3的L Arg静脉注射可增加冠脉结扎后大鼠心肌eNOSmRNA表达 (P <0 0 5 )。结论　①心梗早期大鼠缺血心肌eNOS基因表达减少 ;②L 精氨酸静脉注射增加心梗大鼠缺血心肌eNOSmRNA表达。     

急性缺血与L-精氨酸干预对大鼠心肌组织一氧化氮合酶基因表达的影响

目的观察急性心肌缺血状态下大鼠心脏内皮型和诱生型两种一氧化氮合酶表达和左旋精氨酸（L-Arg）对大鼠心脏组织内生型一氧化氮合酶（eNOS）基因表达的影响。方法60只健康成年SD大鼠随机分为假手术组、缺血组两组。分别取1、2、8、24h四个不同时间点。采用开胸结扎冠状动脉左前降支的方法建立心肌缺血模型,用逆转录聚合酶链式反应（RT-PCR）检测大鼠心梗后不同时间点及L-Arg（30mg&#183;kg-1&#183;次^-1&#215;3）给药后缺血心肌eNOSmRNA表达;免疫组织化学方法检测冠脉结扎后8h缺血心肌诱生型一氧化氮合酶（iNOS）蛋白。结果①冠脉结扎后2h缺血组大鼠缺血心肌组织eNOSmRNA表达下降（P〈0.05）,并持续至结扎后24h;梗死后24h组eNOS mRNA表达与结扎后2h组相比无显著性差异（P〉0.05）。②与生理盐水组相比,L-Arg静脉注射可增加冠脉结扎后大鼠缺血心肌组织细胞eNOS mRNA表达（P〈0.05）。③冠脉结扎后8h,梗死及周围区存活心肌组织细胞出现大量iNOS蛋白表达,而假手术组未见iNOS蛋白表达。结论①正常心肌组织有eNOS基因表达,无iNOS蛋白表达;心肌急性缺血刺激早期诱导大鼠缺血心肌细胞iNOS蛋白大量表达。②在心梗早期缺血心肌组织细胞eNOS基因表达减少。③L-Arg静脉用药可增加急性心肌梗死大鼠缺血心肌组织细胞eNOS mRNA表达。     

一氧化氮合酶mRNA在压力超负荷心肌肥厚中的作用

目的:研究一氧化氮合酶(NOS)mRNA在心肌肥厚发生发展中的作用以及卡托普利防治心肌肥厚的机制。方法:采用腹主动脉狭窄术建立压力超负荷心肌肥厚动物模型,应用RT-PCR方法于术后1、2、4周,分别检测对照组、心肌肥厚组和卡托普利组大鼠左心室心肌组织NOS mRNA表达的变化。结果:①与对照组相比,术后1、2、4周心肌肥厚组大鼠左室重/体重(LVW/BW)指标及SBP均显著升高;左心室eNOS mRNA表达降低,iNOS mRNA表达升高,nNOS mRNA表达无明显变化。②与心肌肥厚组相比,术后1、2、4周卡托普利组大鼠LVW/BW及SBP均显著降低;左心室eNOS mRNA表达升高,iNOS mRNA表达降低,接近对照组。结论: eNOS和iNOS参与心肌肥厚的发生发展过程,但二者起不同作用。卡托普利防治心肌肥厚的作用可能与其调节NOS mRNA表达密切相关。     

高钠饮食对内皮源性血管活性物质水平的影响

目的观察高钠饮食下大鼠血浆和心肌组织中内皮素-1(ET-1)、一氧化氮(NO)、内皮型一氧化氮合酶(eNOS)及eNOS mRNA等浓度,探讨高钠饮食下大鼠血管内皮系统的分子生物学机制。方法 SD大鼠84只随机分为2组:高钠饮食组(n=42),饮用含0.9%氯化钠盐水;对照饮食组(n=42),饮去离子水。适应性喂养2周,实验喂养8周。分别检测血浆及心肌组织ET-1、NO、eNOS浓度及心肌eNOSmRNA表达。结果高钠饮食组血钠及ET-1水平显著性高于对照组(P0.05),eNOS及NO显著性低于对照组(P0.05);高钠饮食组心肌组织NO、eNOS及eNOSmRNA显著性低于对照组(P0.05),心肌组织ET-1水平显著性高于对照组(P0.05)。结论此研究进一步说明高钠饮食通过影响血管内皮系统功能可引起动脉粥样硬化性血管病变及靶器官损害。     

骨髓干细胞心肌内移植增加诱生型一氧化氮合酶的表达

目的:通过研究骨髓干细胞心肌内移植是否影响心脏血管内皮舒张功能相关的一氧化氮合酶(NOS)基因的表达,探讨骨髓干细胞心肌内移植对血管舒张功能的影响机制。 方法:对Lewis大鼠进行冠状动脉前降支结扎和骨髓干细胞梗死区域心肌内移植,术后梗死区域心脏取材。分为急性心肌梗死组、骨髓干细胞心肌内移植组各15只,及正常组3只。用逆转录多聚酶链反应(RT-PCR)方法检测诱生型一氧化氮合酶(iNOS)和内皮源性一氧化氮合酶(eNOS)的表达。 结果:急性心肌梗死组心肌组织中iNOS的表达在1天时明显增高,3天后迅速减低;骨髓干细胞心肌内移植组,心肌组织中iNOS的表达进一步增高,可维持1个月(P<0.01)。急性心肌梗死组以及骨髓干细胞心肌内移植组,心肌组织eNOS的表达没有增加(P>0.05)。 结论:骨髓干细胞心肌内移植增加心肌组织iNOS的表达,延长其表达时间,但不影响心肌组织eNOS的表达。     

内皮型一氧化氮合酶基因导入对高血压大鼠细胞凋亡的影响

目的研究内皮型一氧化氮合酶(eNOS)基因导入对高血压大鼠心脏、肾脏细胞凋亡的影响。方法将实验大鼠分为自发性高血压大鼠(SHR)组、AAV-LacZ组和AAV-eNOS组,每组8只,另设8只正常血压(WKY)大鼠为WKY组。AAV-eNOS组经尾静脉注射AAV-eNOS 200μl(含eNOS基因拷贝1×1012),AAV-LacZ组注射AAV-LacZ 200μl,WKY及SHR组大鼠分别经尾静脉给予等量0.1 mol/L PBS。应用原位末端标记(TUNEL)法检测各组大鼠心、肾组织中的细胞凋亡,免疫组织化学方法检测eNOS的表达。结果①SHR组大鼠心肌组织及肾脏组织染色阳性信号明显增多,与WKY组比较具有显著性差异(P<0.05),AAV-eNOS组凋亡阳性信号明显低于SHR组,差异显著(P<0.05)。②SHR组及AAV-LacZ组大鼠心肌组织eNOS表达低于WKY组,差异具有显著性(P<0.05);与SHR组大鼠比较,AAV-eNOS组eNOS表达明显增加,差异具有显著性(P<0.05)。各组大鼠肾脏eNOS蛋白表达未见明显差异。结论 eNOS基因导入可明显抑制心肌及肾脏组织细胞的凋亡,保护靶器官。     

替罗非班对大鼠心肌缺血再灌注后无复流及一氧化氮合酶活性和一氧化氮含量的影响

目的研究替罗非班对大鼠心肌缺血再灌注后无复流及一氧化氮合酶(NOS)活性、一氧化氮(NO)含量的影响,探讨替罗非班改善心肌缺血再灌注后无复流的作用机制。方法雄性Wistar大鼠,随机分为假手术组、对照组和替罗非班组。建立急性心肌缺血再灌注无复流模型,用硫黄素S活体染色,观察大鼠心肌无复流范围;伊文斯蓝、氯化三苯基四氮唑(TTC)染色评估大鼠心肌缺血及梗死范围;紫外分光光度计测定缺血再灌注120min时缺血区心肌内皮型一氧化氮合酶(eNOS)、诱导型一氧化氮合酶(iNOS)、总一氧化氮合酶(tNOS)活性及NO含量。结果缺血再灌注后120min,替罗非班组大鼠与对照组大鼠心肌缺血范围相似[(43.13±5.69)%比(39.98±3.75)%,P>0.05],但无复流范围及梗死范围明显小于对照组[(34.36±6.04)%比(52.09±6.89)%,P<0.01;(80.41±8.48)%比(90.13±5.72)%,P<0.05);对照组大鼠心肌的eNOS活性低于假手术组,iNOS、tNOS活性及NO含量高于假手术组(P<0.01);替罗非班组大鼠心肌的iNOS活性及NO含量高于假手术组(P<0.05,P<0.01),eNOS、tNOS活性与假手术组差异无统计学意义。与对照组比较,替罗非班组大鼠心肌的eNOS活性高于对照组(P<0.05),iNOS活性及NO含量低于对照组(P<0.05,P<0.01),tNOS活性较对照组有降低的趋势,但差异无统计学意义。结论大鼠心肌缺血90min再灌注120min可发生无复流现象;替罗非班可缩小无复流及梗死范围,其机制可能与保护内皮功能有关。     

一氧化氮合酶在去卵巢大鼠心肌缺血再灌注损伤中的调控作用

目的 研究一氧化氮合酶(NOS)在去卵巢大鼠心肌缺血再灌注(IR)损伤中的调控作用。方法 选取雌性SD大鼠132只,为探究去卵巢对心肌IR损伤的影响,48只大鼠随机分为假手术组、IR组、去卵巢组、联合组,每组12只;为探究内皮型NOS(eNOS)和诱导型NOS(iNOS)在去卵巢加重心肌IR损伤中的作用,84只大鼠IR造模前进行去卵巢、尾静脉注射过表达eNOS或敲低iNOS的腺相关病毒,分为阴性假手术组、阴性IR组、阴性联合组、eNOS+IR组、eNOS联合组、iNOS小干扰RNA(si-iNOS)+IR组、si-iNOS联合组,每组12只。检测每组心肌梗死面积、血清乳酸脱氢酶(LDH)、肌酸激酶同工酶(CK-MB)、LVEF、左心室短轴缩短率(LVFS)及心肌eNOS和iNOS的表达。结果 与IR组比较,联合组心肌iNOS表达、心肌梗死面积、血清LDH和CK-MB水平增高,心肌eNOS表达、LVEF和LVFS水平降低(P<0.05)。与阴性联合组比较,eNOS联合组和si-iNOS联合组心肌梗死面积、血清LDH和CK-MB水平降低[(23.51±3.22)%、(26.21±2....     

比索洛尔对自发性高血压大鼠心室肥厚、心肌纤维化和相关因子的影响

目的 探讨比索洛尔对自发性高血压大鼠(SHR)心肌纤维化、心室肥厚和相关因子的影响.方法 24只SHR随机分为比索洛尔组和对照组,血压正常的Wistar-Kyoto大鼠12只作为正常对照组(WKY组).比索洛尔组将比索洛尔按2mg/kg溶于1mL蒸馏水中灌胃,每日1次,其余两组给予等体积的蒸馏水灌胃,12周后测定左心室重量指数(LVWI)以及心肌羟脯氨酸(HC)浓度,RT-PCR技术检测心肌组织基质金属蛋白酶-2(MMP-2)和血管内皮生长因子(VEGF)mRNA的表达水平.结果 比索洛尔组收缩压明显降低,与治疗前比较差异有统计学意义(P<0.05),HC、LVMI、MMP-2和VEGF表达水平低于对照组(P<0.05).MMP-2和VEGF的表达水平呈正相关((r=0.803,P<0.05).结论 比索洛尔可以抑制自发性高血压大鼠心室肥厚,有效抑制大鼠心肌纤维化的形成,其机制与抑制MMP-2表达水平从而抑制 VEGF的表达有关.     

L-精氨酸对糖尿病大鼠心肌损伤的影响

目的研究L-精氨酸(L-Arg)对糖尿病(DM)大鼠心肌的保护作用。方法 28只大鼠腹腔注射链脲佐菌素(60 mg/kg)制备DM模型,随机均分为DM组、L-Arg〔300 mg/(kg.d)〕治疗组。另设立正常对照(NC)组(n=12)。用药12周末处死大鼠,用透射电镜观察3组大鼠心肌细胞的形态学改变,采用RT-PCR检测心肌组织内皮型一氧化氮合酶(eNOS)、诱导型一氧化氮合酶(iNOS)、内皮素-1(ET-1)mRNA的表达水平,并测定心肌组织内eNOSi、NOS、Na+-K+-ATP酶、Ca2+-ATP酶活性以及一氧化氮(NO)、ET-1的含量。结果电镜下可见DM组大鼠心肌细胞肌原纤维含量明显减少,肌浆网扩张,线粒体肿胀变性。DM组大鼠eNOS mRNA表达、Na+-K+-ATP酶、Ca2+-ATP酶活性及NO含量明显低于NC组,而ET-1 mRNA表达及ET-1含量明显高于NC组。L-Arg组大鼠心肌病变明显减轻,eNOS mRNA表达、Na+-K+-ATP酶、Ca2+-ATP酶活性及NO含量明显高于DM组,ET-1mRNA表达及ET-1含量明显低于DM组。结论 L-Arg对DM大鼠心肌具有保护作用,其机制可能与L-Arg增加心肌组织NO含量、降低ET-1含量,改善心肌血供有关。     

Exhaled nitric oxide

Nitric oxide is a molecule that under normal conditions is synthesised from L-arginine, thanks to the action of the so called NOS-c (nitric oxide synthethase constituents) in different cells, in very small amounts. They behave like a neurotransmitter, modulating different vascular functions of the flat muscle in the aerial vias. However, the synthesis of NO can also come about by means of the action of the so called NOS-i (nitric oxide synthethase inducers) whose expression is induced by endotoxins and different pro-inflammatory cytokines. Their activity gives rise to enlargements of an abrupt nature, that are associated to inflammatory conditions. In asthma it has been proven that there is an increase in the ENO figures, which are above the normal amount that the general population have; causing an inflammatory condition of the air way; a basic characteristic of the pathogenesis of asthma, that conditions the obstruction and the hyper-reactivity of the air ways that conclude in defining asthma according to the current concept. Until now, the valuation of the inflammation of the aerial vias is done by serum determinations of other inflammatory markers that are subject to other influences and some of them are not very reliable, apart from being expensive; or by determinations of these markers in induced sputum, or bronchoalveolar ablution. The difficulty of obtain this type of samples in young children means that it is not viable to use this system to assess the inflammation for daily practice. The determination of the ENO in the expired air is carried out by the chemoluminiscence measurement of the synthesis of O2N produced after the NO reacts with the ozone. This is a photochemical reaction and emitys infrared light in proportion to the concentration of the NO in the exhaled air. In the presentation, we will try to analyse the role that the ENO plays on the inflammatory pathology of the respiratory tree; which techniques we can use to measure it; for which reasons the measurement can be altered and finally how it behaves in respiratory allergy. In general the literature on this theme, which is very extensive, shows some defects: there is a disparity in the methods used to collect exhaled air, the pathological situations which determine the ENO are different (for example: patients being treated with inhaled corticoids and people who have never been treated with corticoids) the groups of patients are small and all this together makes it difficult to understand the value of the determination of the ENO in daily practise. But this does not mean that we feel isn't useful, on the contrary: it confirms the need to study the behaviour of the ENO levels in asthma, both in basal situations as well as in relation to the treatment of this illness.     

Inhaled nitric oxide

Inhaled NO offers a novel therapy for the treatment of pulmonary hypertensive diseases and the symptomatic relief of hypoxemia. The use of iNO reduces the necessity for ECMO in newborns and infants with acute hypoxemic respiratory failure. Proper indications, contraindications, dosing criteria, and implications of the toxic actions of NO must be delineated fully. Randomized clinical trials of patients with carefully defined, specific acute disease states that are characterized by pulmonary hypertension or hypoxemia have not been completed.     

一氧化氮和一氧化氮合酶与肿瘤放疗敏感性的关系

一氧化氮(nitricoxide,NO)的生物学作用具有复杂性和多样性,在基础条件下诱导型一氧化氮合酶(induciblenitricoxidesynthase,iNOS)活性很低,当机体遭受微生物内外毒素、炎症介质等刺激时iNOS可诱导合成大量的NO.肿瘤生物学上一般认为高水平的NO对肿瘤细胞具有直接的细胞毒作用,而较低水平的NO具有生长刺激作用.多种试验显示NO的供体能增加肿瘤的放疗敏感性.研究认为,NO的生物学作用可能是通过p53依赖途径介导的.调节NO杀灭肿瘤或促进肿瘤生长,p53起到关键性的作用.已有多种药品作为放射敏化剂,NO供体药物在体内给药可能导致系统低血压,增加肿瘤血液灌注和氧合作用,具有潜在的促进肿瘤生长的作用,限制了其临床使用.直接将iNOS基因转染入肿瘤细胞内,肿瘤内的乏氧环境,可降低iNOS的活性而影响NO的产量.携带iNOS基因的腺病毒(adenoviralvectorcarryingtheiNOScDNA,AdiNOS)转染靶细胞导致iNOS过表达,产生大量NO,有望成为一种增加肿瘤放疗敏感性有效可行的方法.     

梅毒患者血清一氧化氮和一氧化氮合酶水平测定

目的　检测梅毒螺旋体感染者血清中一氧化氮 (NO)和一氧化氮合酶 (NOS)的水平。方法　用分光光度法测定血清中NO水平和NOS活性 ,血清中NO3 和NO2 总量代表体内NO水平 ,NOS催化L 精氨酸和氧的反应生成NO的多少代表血清NOS活性。结果　梅毒患者NO浓度为 115± 36 3nmol/L ,NOS活性为 35 8± 7 3U/ml,二者均远远高于正常对照组。结论　梅毒螺旋体的感染引起患者体内NO水平和NOS活性升高 ,NO在梅毒感染中可能发挥重要的作用。     

cGMP-mediated negative-feedback regulation of endothelial nitric oxide synthase expression by nitric oxide

Earlier studies have demonstrated that nitric oxide (NO) exerts a fast-acting inhibitory influence on endothelial NO synthase (eNOS) enzymatic activity in isolated vascular tissue preparations. The present study was designed to examine the possible effect of NO on eNOS protein expression in cultured endothelial cells and intact animals. Human coronary endothelial cells were incubated with S-nitroso-N-acetyl-penicillamine (SNAP, an NO donor), oxyhemoglobin (HGB, an NO trapping agent), SNAP plus HGB, or inactive vehicle (control). In other experiments, cells were treated with 3-isobutyl-1-methylxanthine (a phosphodiesterase inhibitor), 1H-[1,2, 4]oxadiazolo-[4,3-2]quinoxalin-1-one (ODQ, a guanylate cyclase inhibitor), SNAP plus ODQ, 8-bromo-cGMP (8-Br-cGMP, a cell-permeable cGMP compound), 8-Br-cGMP plus HGB, or inactive vehicle in order to discern the effect of cGMP. The incubations were conducted for 24 hours, and total nitrate plus nitrite production and eNOS protein abundance (Western analysis) were measured. To determine the effect of NO on eNOS expression in vivo, rats were treated with either the NO donor isosorbide dinitrate or placebo by gastric gavage for 48 hours, and aortic eNOS protein expression was examined. The NO donor SNAP markedly depressed, whereas the NO scavenger HGB significantly raised, eNOS protein expression. The downregulatory action of SNAP was completely abrogated by HGB. Phosphodiesterase inhibitor and 8-Br-cGMP downregulated, whereas the guanylate cyclase inhibitor ODQ upregulated eNOS protein expression. The downregulatory action of SNAP was completely overcome by the guanylate cyclase inhibitor ODQ, and the upregulatory action of the NO scavenger HGB was abrogated by 8-Br-cGMP. Administration of NO donor resulted in a marked downregulation of aortic eNOS protein expression in intact animals, thus confirming the in vitro findings. NO serves as a negative-feedback regulator of eNOS expression via a cGMP-mediated process.     

Novel features of nitric oxide,endothelial nitric oxide synthase,and atherosclerosis

There is a complex pathophysiologic scenario involving nitric oxide (NO), endothelial nitric oxide synthase (_eNOS), and the development of atherosclerosis and unstable atheroma. Endothelial damage induced by atherosclerosis leads to the reduction in bioactivity of _eNOS with subsequent impaired release of NO. An important mechanism is local enhanced degradation of NO by increased generation of reactive oxygen species and other free radicals, with subsequent cascade of oxidationsensitive mechanisms in the arterial wall. Novel molecular approaches have resulted in the development of new strains of mice lacking _eNOS. These experimental models will help to understand how to implement NO-based therapies against atherosclerosis. L-arginine, the precursor of NO, has demonstrated beneficial effects in atherosclerosis and disturbed shear stress. The target or goal for new drugs should be the complete restoration of NOmediated signaling pathways in atherosclerotic arteries.