血管紧张素Ⅱ及其受体在慢性间歇低氧诱发大鼠高血压发病过程中的动态变化

目的　观察慢性间歇低氧诱发大鼠高血压发病过程中血管紧张素Ⅱ (ATⅡ )及其受体的动态变化 ,并探讨其在慢性间歇低氧诱发高血压发病机制中的作用。方法　 72只雄性Wistar大鼠随机均分为间歇低氧组 (IH组 )、实验对照组 (SC组 )和空白对照组 (UC组 ) ;IH组大鼠循环给予氮气和压缩空气 (每一循环 6 0s,使舱内最低氧浓度达 4 %～ 6 % ,然后恢复至 2 1% ,8h/d) ,SC组大鼠循环给予压缩空气 ,UC组大鼠不予任何处理。观察第 7、2 1、4 2天时各组大鼠血压、血浆肾素活性 (RA)和ATⅡ水平以及不同组织ATⅡ 1型受体 (AT1R)mRNA的表达。结果　第 4 2天时IH组大鼠平均动脉压(MAP)为 (10 2 2± 6 2 )mmHg(1mmHg =0 133kPa) ,显著高于SC组 [(95 7± 3 6 )mmHg]、UC组 [(97 2±3 6 )mmHg ,P均 <0 0 5 ]和实验前水平 [(94 1± 4 3)mmHg ,P <0 0 1];IH组大鼠血浆RA从第 7天[(3 86± 1 2 5 )ng·ml-1·h-1]开始显著高于SC[(2 73± 0 98)ng·ml-1·h-1]、UC组 [(2 5 5± 0 87)ng·ml-1·h-1,P均 <0 0 5 ],血浆ATⅡ从第 2 1天 [(2 14± 4 1)ng/L]开始显著高于SC[(12 4± 2 1)ng/L]、UC组 [(12 1± 18)ng/L ,P均 <0 0 1];并且血浆RA和ATⅡ水平与MAP均呈正相关 (r =0 5 2 9,P =0 0 0 8和r=0 4 75 ,P =0 0 19     

L-精氨酸对低氧性肺动脉高压大鼠肺动脉平滑肌细胞凋亡的影响

目的 探讨L-精氨酸(L-Arg)对低氧性肺动脉高压大鼠不同节段肺动脉平滑肌细胞凋亡的影响。方法 将Wistar大鼠(n=19)随机分为对照组(n=7)、低氧组(n=6)及低氧 L-Arg组(n=6)。经右心导管法测定各组大鼠肺动脉压力和右室(RV)/左室 室间隔(LV S)比值,以分光光度法间接测定血浆一氧化氮(NO)含量,通过TUNEL法检测各组大鼠不同节段的肺动脉平滑肌细胞凋亡数目,并计算肺动脉平滑肌细胞凋亡数目与肺动脉平滑肌细胞数目比值。结果 低氧组大鼠肺动脉平均压(PAMP)显著高于对照组[(2.71±0.29)kPa vs(2.05±0.14)kPa,P<0.01],低氧 L-Arg组大鼠的PAMP显著低于低氧组[(2.23±0.18)kPa vs(2.71±0.29)kPa,P<0.05];低氧组大鼠RV/(LV S)比值显著高于对照组[(0.42±0.03)kPa vs(0.30±0.05)kPa,P<0.01],低氧 L-Arg组大鼠RV/(LV S)比值显著低于低氧组[(0.36±0.02)kPa vs(0.42±0.03)kPa,P<0.01];低氧组大鼠血浆NO含量明显低于对照组[(3.54±0.47)μmol/L vs(4.79±0.17)μmol/L,P<0.05],低氧 L-Arg组大鼠血浆NO含量显著高于低氧组[(5.21±0.26)μmol/L vs(3.54±0.47)μmol/L,P<0.01];低氧组大鼠与终末细支气管伴行的肺动脉和与呼吸细支气管伴行的肺动脉平滑肌细胞凋亡数目与平滑肌细胞数目比值明显低于对照组[(0.051±0.016     

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。     

间歇缺氧小鼠血清一氧化氮水平变化趋势的研究

目的 观察慢性间歇缺氧（chronic intermittent hypoxia ,CIH）小鼠一氧化氮（nitric oxide ,NO）水平的变化趋势。方法 将12只11周龄雄性小鼠随机等分为两组,CIH组于间歇缺氧饲养,对照（UC）组于常氧饲养,分别于第2、6、9周抽血,采用ELISA法检测小鼠NO水平。结果 ①CIH组与UC组比较：第2、6周CIH组小鼠NO水平均明显低于UC组[分别为（1.3±0.59）umol/L比（3.34±0.92）umol/L,（3.9±0.83）umol/L比（7.11±1.68）umol/L],差异有统计学意义（t=3.67,P<0.05;t=3.34,P<0.05）;第9周CIH组小鼠NO水平低于UC组[分别为（1.76±0.72）umol/L比（2.45±0.77）umol/L],但差异无统计学意义（t=1.31,P>0.05）。②CIH组间比较：第6周NO水平明显高于第2周,差异有统计学意义（P<0.01）;第9周NO水平明显低于第6周,差异有统计学意义（P<0.01）。③UC组比较：第6周NO水平明显高于第2周,差异有统计学意义（P<0.01）;第9周NO水平明显低于第6周,差异有统计学意义（P<0.01）。结论 ①间歇缺氧过程中NO水平明显均低于对照组,至血管内皮保护功能下降;②间歇缺氧第2周出现NO水平降低,早期即可导致血管内皮保护功能下降;③两组第6周小鼠血清NO水平均明显高于第2周,第9周小鼠血清NO水平均明显低于第6周,可能衰老及炎症反应［诱导性一氧化氮合酶（iNOS）］参与调控血管内皮的保护作用;④CIH组第6周NO水平代偿性升高,第9周失代偿下降,建议 OSA治疗时机选择最好在间歇缺氧6周前。     

硅对大鼠血清一氧化氮合酶及一氧化氮的影响

目的　观察硅 ( Na2 Si O3)对血清中一氧化氮合酶 ( NOS)及一氧化氮 ( NO)浓度的影响 ,探讨其抗动脉粥样硬化 ( AS)的作用。方法　高脂饮食饲养 SD大白鼠造成高脂血症和早期 AS模型 ,造模时以 Na2 Si O3 溶液灌胃 ,1 0 w后比较各组血清中 NOS活性和 NO浓度以及动脉壁形态。结果　与正常对照组比较 ,早期 AS时大鼠血清 NOS活性下降 (分别为 2 9.2 3± 1 .837和 2 7.4 3± 2 .0 0 U/ml,P<0 .0 5) ,NO总浓度增加 (分别为35.71± 1 4.4 7和 1 90 .57± 76 .4 3μmol/L ,P<0 .0 1 )。灌胃 Na2 Si O3 溶液 ( 1 0 mg/k g.d )后 NOS及 NO总浓度均恢复到正常组水平。结论　 Na2 Si O3可调节动脉硬化大鼠体内 NO代谢 ,发挥抗 AS作用     

盐酸贝尼地平对大鼠硝酸甘油耐受性的影响及机制

目的观察盐酸贝尼地平对硝酸甘油(NTG)耐受性的影响及其机制。方法通过描记大鼠舒张反应性曲线,测出各种NTG浓度时舒张反应百分率,检测血管组织中的丙二醛(MDA)含量、一氧化氮(NO)含量、一氧化氮合酶(NOS)活性和环磷酸鸟苷(cGMP)含量。结果通过对照NTG+盐酸贝尼地平组和NTG组发现,盐酸贝尼地平可以显著减少MDA含量[(7.83±1.41)比(14.37±0.88)μmol/g蛋白,P<0.05];增加NO的含量[(78.88±1.75)比(70.30±1.74)mmol/g蛋白,P<0.05];增加cGMP含量[(200±19)比(169±13)pmol/g蛋白,P<0.05];未增加NOS的活性[(310±20)比(290±30)U/g蛋白,P>0.05]。结论盐酸贝尼地平可以通过抗氧化作用,减少氧自由基的产生,使NTG源NO灭活减少和组织中NO含量增加;增加cGMP含量和活性,从而恢复NO信号传递系统完整性。     

一氧化氮在肝硬化大鼠睾丸功能障碍发生中的作用

目的探讨一氧化氮(NO)在肝硬化睾丸功能障碍发生中的作用. 方法采用胆管结扎(BDL)复制肝硬化模型,应用硝酸酶还原法测定大鼠血清和睾丸组织匀浆的NO浓度,应用放射免疫分析法测定血清睾酮浓度,同时检测大鼠附睾精子密度和精子活率. 结果肝硬化(HC)组大鼠血清和睾丸组织匀浆NO水平分别为(4.165±1.162)μmol/L和(1.305±0.087)μmol/g,假手术(SO)组大鼠血清和睾丸组织匀浆NO水平分别为(0.535±0.237)μmol/L和(0.720±0.063)μmol/g,HC组显著高于SO组.HC组血清睾酮水平[(0.049±0.020)μg/L]、附睾精子活率(16.46%±4.84%)及精子密度[(86.89±33.17)×106个/ml]均显著低于SO组[分别为(2.680±0.403)μg/L、62.45%±9.21%和(299.43±53.85)×106个/ml],而持续给予小剂量NOS抑制剂L-NAME(HC-NAME组)(0.5mg@kg-1@d-1)达一周,HC-NAME组大鼠血清及睾丸组织NO水平分别为(1.975±0.406)μmol/L和(0.950±0.057)μmol/g,较HC组显著降低.同时HC-NAME组血清睾酮水平、附睾精子活率和精子密度较HC组均显著增高,分别为(0.993±0.179)μg/L、33.85%±4.93%和(188.94±38.34)×106个/ml. 结论 NO在肝硬化大鼠睾丸功能障碍发生中起重要作用,小剂量应用NOS抑制剂L-NAME,肝硬化大鼠NOS持续抑制引起的睾丸功能障碍得到不同程度改善,表明在治疗肝硬化睾丸功能障碍患者时体内给予NOS抑制剂的可能性.     

间歇低氧对人脐静脉内皮细胞中内皮素的影响

目的通过建立间歇低氧细胞模型,测定不同低氧模式下人脐静脉内皮细胞中内皮素(endothelin,ET)含量的变化,以进一步探讨ET在细胞水平对间歇低氧在阻塞性睡眠呼吸暂停综合征合并高血压患者中的作用.方法采用人脐静脉内皮细胞可传代细胞株ECV304细胞系,暴露于不同低氧条件,暴露完成后采用双抗夹心酶联免疫吸附法(ELISA法)测定培养基中ET浓度.结果间歇低氧组ET浓度[(12.86±6.68)pg/mL]与间歇正常氧组[(3.29±0.88)pg/mL]及空白对照组[(4.67±1.22)pg/mL]间差异有统计学意义(F=13.687,P<0.05).其中,间歇低氧组高于间歇正常氧组(P<0.05)及空白对照组(P<0.05),而间歇正常氧组及空白对照组间差异无统计学意义(P>0.05).相同累加低氧时间及程度的间歇低氧组ET浓度显著高于持续低氧组[(7.07±1.00)pg/mL](P<0.05).结论间歇低氧可引起ET水平升高,提示ET在间歇低氧合并高血压中可能起重要作用.     

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。     

慢性间歇低氧老龄大鼠脑血管内皮功能的研究

目的 探讨慢性间歇低氧(CIH)对老龄鼠脑血管及内皮素-1(ET-1)、一氧化氮(NO)、血管内皮生长因子(VEGF)表达的影响.方法 应用间歇低氧处理方式建立CIH老龄大鼠实验模型,实验3、6、9周后,检测血浆ET-1、NO和VEGF的含量;观察脑血管病理变化与脑组织中小动脉血管壁厚度与外径之比(WT%)与VEGF蛋白的表达.结果 CIH组血ET-1、VEGF表达均增加,NO表达减弱,从第3周ET-1含量较空白对照(UC)组增高(t=2.47,P<0.05),VEGF含量较空白对照(UC)组升高(t=2.38,P<0.05),NO含量较UC组降低(t=2.39,P<0.05).VEGF水平与间歇低氧时间呈正相关,第9周[(171.1±13.5)pg/ml]表达最强,与第3周[(129.3±12.3)pg/ml]比较升高明显(t=2.38,P<0.05),较UC组[(109.8±8.6)pg/ml]增高(t=3.46,P<0.01).光镜下UC组脑血管未见明显的病理变化,CIH组可见脑细胞水肿和血管增生.CIH组大鼠脑小动脉WT%改变从第3周即强于UC组(t=2.34,P<0.05),脑组织VEGF的表达在CIH组各时间段均显著高于UC组(t=2.37,P<0.05),随着CIH作用时间的累积,脑组织VEGF和脑小动脉WT%改变均有加重的趋势,第9周明显高于第3周(t=2.32和t=2.35,均P<0.05).结论 CIH可诱导老龄大鼠ET-1、VEGF表达增强,NO水平下降,导致脑细胞肿胀,小动脉管壁增厚,管腔狭窄,提示纠正VEGF、ET-1/NO的表达紊乱应成为OSAS综合防治的一个重要方面.     

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.     

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.