天麻酚类成分对脑缺血模型大鼠海马一氧化氮和一氧化氮合酶的影响

目的探讨天麻酚类成分对脑缺血大鼠海马NO和一氧化氮合酶(NOS)的影响。方法采用双侧颈总动脉永久性结扎法,造成大鼠脑缺血模型。造模6周后,SD大鼠40只随机分为5组,假手术组、模型组、尼莫地平组、天麻酚类成分高剂量组(高剂量组)和天麻酚类成分低剂量组(低剂量组),每组8只。给药3周后,比色法检测海马NO含量和NOS活性,免疫印记法检测大鼠海马NOS 3种亚型(nNOS,iNOS,eNOS)的表达。结果与假手术组比较,模型组大鼠海马NO含量、NOS活性及nNOS和iNOS表达明显升高,eNOS表达明显降低;与模型组比较,尼莫地平组和高剂量组大鼠海马NO含量、NOS活性及nNOS和iNOS表达明显降低,eNOS表达明显升高;低剂量组大鼠NOS活性和iNOS表达明显降低,差异有统计学意义(P<0.05,P<0.01)。结论天麻酚类成分对脑缺血大鼠海马NO损伤有保护作用。     

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。     

异丙肾上腺素诱导的急性心肌损伤大鼠一氧化氮系统的变化

目的建立异丙肾上腺素(ISO)诱导的急性心肌损伤大鼠模型,观察急性心肌损伤大鼠NO系统的变化。方法将SD大鼠随机分为两组,对照组和模型组。模型组连续3d皮下注射ISO(150mg·kg-1·d-1)。通过血清肌酸激酶(CK)和乳酸脱氢酶(LDH)的活性和Ⅱ导联心电图来判定心肌损伤与否。用荧光定量RT-PCR来分析三种一氧化氮(eNOS、nNOS、iNOS)以及肿瘤坏死因子-α(TNF-α)的mRNA转录水平。结果模型组血清CK、LDH的活性显著增加(P<0.001),ST段明显上抬。与正常组相比,模型组eNOS和nNOS的转录水平显著降低(P<0.001);而iNOS和TNF-α的转录水平显著升高(P<0.001)。结论ISO诱导的心肌损伤大鼠NO系统发生的主要变化为三种NOS转录水平的改变。     

全氟化碳对心肌缺血再灌注损伤后大鼠NO、NOS的影响

目的探讨全氟化碳(PFC)对心肌缺血再灌注损伤(IRI)后大鼠一氧化氮(NO)和一氧化氮合酶(NOS)的影响。方法将75只雄性Wistar大鼠随机分为5组,假手术组、缺血再灌注(RI)组、PFC低剂量组、PFC中剂量组、PEC高剂量组各15只。结扎大鼠冠脉左前降支,使心肌缺血30 min、再灌注120 min,制成心肌IRI模型。应用硝酸还原酶法检测心肌组织中的NO水平,化学比色法检测总NOS(tNOS)、内皮型NOS(eNOS)、诱导型NOS(iN-OS)活性。结果与假手术组比较,各组心肌组织中的NO水平及tNOS、eNOS活性降低(P均<0.05);与RI组比较,PFC中、高剂量组各指标升高(P均<0.05)。各组iNOS活性比较无统计学差异(P>0.05)。结论 PFC可减少心肌IRI后大鼠心肌组织中的NO水平,提高其eNOS活性,改善心肌IRI。     

溃疡性结肠炎和一氧化氮合酶的表达

溃疡性结肠炎(UC)是常见的肠道炎症性疾病，发病率有逐年升高的趋势。文献报道，UC患者结肠内一氧化氮(NO)明显升高。NO合成有赖于一氧化氮合酶(NOS)的作用，NOS按其来源分为3种类型：神经型(nNOS)、内皮型(eNOS)和诱生型(iNOS)。前两种合称为结构型NOS(cNOS)。cNOS是钙离子和钙调蛋白依赖性酶，持续释放少     

藻蓝蛋白在脑缺血再灌注损伤过程中的抗氧化作用

目的研究脑缺血再灌注神经细胞一氧化氮合酶(NOS)的表达以及藻蓝蛋白的抗氧化作用机制。方法随机将52只Wistar大鼠分为假手术组(4只)、对照组(24只)和治疗组(24只);后两组再分为脑缺血1 h再灌注6、12 h,13、、7及14天组,每组4只。应用线栓法制作大鼠大脑中动脉阻塞再灌注(MCAO/R)模型[1],藻蓝蛋白进行干预,采用免疫组织化学方法分别观察神经元型NOS(nNOS)、内皮型NOS(eNOS)、诱导型NOS(iNOS)的表达以及藻蓝蛋白的干预作用。结果假手术组脑组织中nNOSi、NOS和eNOS有微弱表达,脑缺血再灌注后6 h,皮质区和纹状体区nNOSi、NOS和eNOS逐渐表达增强,于24 h达高峰,之后逐渐减弱,至7~14 d仍高于假手术组。治疗组NOS变化趋势与对照组相似,与对照组同一时间点比较,nNOS和iNOS表达明显低,eNOS表达明显增强。结论脑缺血再灌注损伤后,藻蓝蛋白可能通过降低脑组织中nNOS和iNOS表达,上调eNOS的表达,而发挥其抗氧化作用。     

肝硬化大鼠内脏血管一氧化氮合酶基因表达及活性的动静脉差异

目的观察肝硬化内脏血管一氧化氮合酶(NOS)表达及活性的动静脉差异在门静脉高压形成机制中的意义.方法以四氯化碳皮下注射制备大鼠门静脉高压模型,应用免疫组织化学、化学发光以及RT-PCR分别检测大鼠门静脉(PV)和肠系膜动脉(MA)组织NOS的分布、活性及基因表达.结果肝硬化组大鼠PV和MA血管各层均有iNOS分布,而eNOS则局限于内皮层.肝硬化大鼠内脏血管NOS活性[pmol.min-1.mg-1.蛋白(PV 23.82±2.48,MA 43.46±4.93)]及mRNA表达均较对照组(PV 16.48±1.54,MA 16 95±2.34)显著升高(P＜0.05与0.01);同时肝硬化大鼠MA的总NOS活性和eNOS活性及eNOS mRNA表达均显著高于PV(P＜0.01).结论内脏血管eNOS亚型活性及表达增加可能在肝硬化时NO产生增多中起主要作用,而NOS活性及表达在MA与PV之间的动静脉差异,可能是NO参与门脉高压形成的重要机制之一.     

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。     

糖尿病大鼠阴茎组织NOS各亚型表达及细胞凋亡的研究

用免疫组化及逆转录PCR研究糖尿病大鼠阴茎组织NOS各亚型的表达水平，并用TUNEL法观察细胞凋亡情况。发现糖尿病大鼠阴茎组织nNOS、eNOS表达减少而iNOS表达增加，细胞凋亡指数升高，这可能是糖尿病性勃起功能障碍的发病机制。     

不同HO-1表达水平对糖尿病模型大鼠血管舒张功能及NOS的影响

目的 探讨改变血红素加氧酶-1(HO-1)表达水平对糖尿病(DM)大鼠血管舒张功能的影响及与一氧化氮合酶(NOS)/一氧化氮(NO)的关系.方法 以链脲佐菌素(STZ)诱导DM大鼠模型.SD大鼠分成4组:对照组、DM组、正铁血红素(HO-1诱导剂)组、锌原卟啉(HO-1抑制剂)组.应用离体血管张力检测技术观察胸主动脉舒张功能变化;RT-PCR法及比色法分别检测血管组织和血清中诱生型NOS(iNOS)及内皮型NOS(eNOS)的表达和NO含量.结果 与DM组相比,正铁血红素组血管环对乙酰胆碱舒张百分率有所提高,而锌原卟啉组血管舒张反应继续下降.应用正铁血红素可在提高DM大鼠血管和血清eNOS表达的同时降低iNOS/NO表达;而锌原卟啉组血清中iNOS活性及其在血管组织表达均增高.结论 提高HO-1的表达水平有益于改善DM大鼠血管舒张反应失调,这种保护作用与抑制iNOS/NO的生成、上调eNOS表达水平有关.     

脂多糖对大鼠不同组织中一氧化氮合成酶基因表达的影响

通过Northernblot和NADPH－心肌黄酶染色显示一氧化氮合成酶活性的组织化学分析方法，观察了脂多糖对大氧心脏、主动脉和肾组织中诱导型一氧化氮合成酶基因表达的影响及诱导型一氧化氮合成酶被脂多糖诱导表达的动力学。结果表明，未经脂多糖处理的大鼠诱导型一氧化氮合成酶基因在所检测的三种组织中表达活性很低，脂多糖作用于大鼠2h，心、肾和主动脉中的诱导型一氧化氮合成酶mRNA开始增加，6h达到峰值，此后，逐渐下降，24h回复到对照水平。一氧化氮合成酶组织化学染色显示，对照大鼠的组织细胞内存在较低的组成型一氧化氮合成酶活性，被脂多糖处理不同时间后，三种组织中的一氧化氮合成酶活性均显著升高，到24h仍维持在较高水平，提示诱导型一氧化氮合成酶被合成后，在组织细胞内较为稳定。     

Deletion of neuronal NOS prevents impaired vasodilation in septic mouse skeletal muscle

OBJECTIVE: Sepsis-stimulated nitric oxide (NO) production impairs arteriolar responsiveness in skeletal muscle. Using wild type (WT), eNOS(-/-), iNOS(-/-) and nNOS(-/-) mice, we aimed to determine the key nitric oxide synthase (NOS) isoenzyme(s) responsible for the arteriolar hyporesponsiveness to acetylcholine (ACh) in septic skeletal muscle. METHODS: Sepsis was induced by the cecal ligation and perforation procedure (24 h model). We measured the post-ACh increase in red blood cell velocity (V(RBC)) in a capillary fed by the stimulated arteriole as an index of vasodilation. NOS activity and protein expression in the muscle were measured by standard procedures. RESULTS: In all non-septic mice, ACh increased V(RBC) by approximately 150% from baseline. Sepsis impaired this response in WT, eNOS(-/-) and iNOS(-/-) mice, but not in nNOS(-/-) mice. Accordingly, pharmacological inhibition of nNOS with 7-nitroindazole reversed this impairment in WT mice. cNOS (eNOS+nNOS) activity was elevated in septic WT mice; Western blots indicated that this occurred through a post-translational mechanism. iNOS protein activity/expression was negligible. ACh caused dilation via endothelial-derived relaxing factor (EDRF) in WT mice and via endothelial-derived hyperpolarizing factor (EDHF) in eNOS(-/-) mice. Although exogenous NO reduced EDHF-mediated dilation in eNOS(-/-) mice, NOS inhibition did not reverse the sepsis-impaired dilation in these mice. CONCLUSIONS: In our 24-h mouse model of sepsis, NO in skeletal muscle is primarily derived from nNOS. Sepsis impairs both EDRF- and EDHF-mediated dilation in response to ACh. Both genetic deletion and inhibition of nNOS protect against this impairment when the dilation occurs via the EDRF but not EDHF pathway.     

Functional inhibition of constitutive nitric oxide synthase in a rat model of sepsis

Induction of inducible nitric oxide synthase (iNOS) expression is likely important in the pathogenesis of sepsis. However, the sepsis-mediated induction of iNOS is associated with a decrease in constitutive NO synthase (cNOS) activity (which is reversible following acute but not chronic sepsis). Whether this decreased cNOS activity is due to functional inhibition of cNOS by the high concentrations of NO produced by iNOS or to downregulation of cNOS expression is not clear. Thus, we tested the hypothesis that sepsis produces a reversible iNOS/NO-mediated inhibition of cNOS activity. Using a rat cecal ligation and perforation (CLP) model of sepsis, we examined the time course of the changes in iNOS and cNOS activities in lung and thoracic aortae. Reversibility of the sepsis-induced decrease in cNOS activity was assessed in vitro by enzyme activity determination following selective inhibition of iNOS. iNOS and endothelial cNOS protein concentrations were determined by Western blotting. In all septic tissues, cNOS activity was depressed at 6, 12, 24, and 48 hours post-CLP. Inhibition of the increased iNOS activity with aminoguanidine, in vitro, partially restored cNOS activity following acute (6-12 hours) but not chronic sepsis (24-48 hours post-CLP). Consistent with the irreversible depression of cNOS activities in tissues following chronic sepsis, endothelial NOS protein concentrations declined progressively during the time course of sepsis. We have demonstrated the restoration of cNOS activity following in vitro inhibition of iNOS, early, and the downregulation of endothelial NOS, later, in a rat CLP model of sepsis. This suggests that further study is required before iNOS-selective inhibition can be considered in human sepsis.     

Long-Acting Calcium Channel Blocker,Azelnidipine, Increases Endothelial Nitric Oxide Synthase in the Brain and Inhibits Sympathetic Nerve Activity

Nitric oxide (NO) in the central nervous system inhibits sympathetic nerve activity, thereby decreasing blood pressure. It is unknown, however, whether orally administered antihypertensive treatment alters NO synthase (NOS) expression, particularly in the brain, and how changes in NOS expression affects sympathetic nerve activity. Azelnidipine, a recently developed long-acting dihydropyridine calcium channel blocker, does not cause baroreflex-induced tachycardia. The aim of the present study was to determine whether antihypertensive treatment with azelnidipine alters endothelial NOS (eNOS), neuronal NOS (nNOS), or inducible NOS (iNOS) expression in the brain, and how changes in NOS affect sympathetic nerve activity. Azelnidipine (20 mg/kg/day) or hydralazine (20 mg/kg/day) was orally administered for 30 days in stroke-prone spontaneously hypertensive rats (SHRSP). Blood pressure and heart rate were measured by the tail cuff method. Urinary norepinephrine excretion was measured as a marker of sympathetic nerve activity. Western blot analysis was performed to examine eNOS, nNOS, or iNOS expression levels in the brain (cortex, cerebellum, hypothalamus, and the brain stem), heart, and aorta. The extent of blood pressure reduction was similar between the two groups. Heart rate increased in the hydralazine-treated group but did not change in the azelnidipine-treated group. Urinary norepinephrine excretion was significantly increased only in the hydralazine-treated group. Treatment with azelnidipine significantly increased eNOS expression levels in the brain, heart, and aorta, but did not alter nNOS or iNOS expression levels. Treatment with hydralazine did not change any of the NOS expression levels. These results suggest that antihypertensive treatment with azelnidipine attenuates reflex-induced sympathetic activation and enhances eNOS expression levels in the brain as well as in the heart and aorta.     

Long-acting calcium channel blocker, azelnidipine, increases endothelial nitric oxide synthase in the brain and inhibits sympathetic nerve activity

Nitric oxide (NO) in the central nervous system inhibits sympathetic nerve activity, thereby decreasing blood pressure. It is unknown, however, whether orally administered antihypertensive treatment alters NO synthase (NOS) expression, particularly in the brain, and how changes in NOS expression affects sympathetic nerve activity. Azelnidipine, a recently developed long-acting dihydropyridine calcium channel blocker, does not cause baroreflex-induced tachycardia. The aim of the present study was to determine whether antihypertensive treatment with azelnidipine alters endothelial NOS (eNOS), neuronal NOS (nNOS), or inducible NOS (iNOS) expression in the brain, and how changes in NOS affect sympathetic nerve activity. Azelnidipine (20 mg/kg/day) or hydralazine (20 mg/kg/day) was orally administered for 30 days in stroke-prone spontaneously hypertensive rats (SHRSP). Blood pressure and heart rate were measured by the tail cuff method. Urinary norepinephrine excretion was measured as a marker of sympathetic nerve activity. Western blot analysis was performed to examine eNOS, nNOS, or iNOS expression levels in the brain (cortex, cerebellum, hypothalamus, and the brain stem), heart, and aorta. The extent of blood pressure reduction was similar between the two groups. Heart rate increased in the hydralazine-treated group but did not change in the azelnidipine-treated group. Urinary norepinephrine excretion was significantly increased only in the hydralazine-treated group. Treatment with azelnidipine significantly increased eNOS expression levels in the brain, heart, and aorta, but did not alter nNOS or iNOS expression levels. Treatment with hydralazine did not change any of the NOS expression levels. These results suggest that antihypertensive treatment with azelnidipine attenuates reflex-induced sympathetic activation and enhances eNOS expression levels in the brain as well as in the heart and aorta.     

Atorvastatin causes depressor and sympatho-inhibitory effects with upregulation of nitric oxide synthases in stroke-prone spontaneously hypertensive rats

OBJECTIVE: Recent studies have suggested that statins decrease blood pressure in hypertensive animals and upregulate endothelial nitric oxide synthase (eNOS) expression. However, the effects of statins on the expression of nitric oxide synthase (NOS) in the brain and the sympathetic nervous system remain to be elucidated. The aim of this study was thus to examine the effects of atorvastatin on blood pressure, sympathetic nerve activity, and the expression of NOS in stroke-prone spontaneously hypertensive rats (SHRSP) as well as in Wistar-Kyoto (WKY) rats. METHODS: The animals received atorvastatin (50 mg/kg per day) for 30 days. Systolic blood pressure and heart rate were evaluated using the tail-cuff method. Urinary norepinephrine excretion was measured for 24 h. The expression of eNOS, neuronal NOS (nNOS), and inducible NOS (iNOS) in the brain (cortex, cerebellum, hypothalamus and brainstem), aorta and heart were determined by Western blot analysis. RESULTS: Systolic blood pressure and 24-h urinary norepinephrine excretion were significantly decreased in SHRSP, but not in WKY, after the treatment with atorvastatin. The eNOS and iNOS expression in the brain and aorta was significantly increased in atorvastatin-treated SHRSP and WKY. However, the nNOS expression in the brain was not altered in the atorvastatin-treated group. CONCLUSIONS: These results suggest that atorvastatin decreases blood pressure, at least in part via the reduction of sympathetic nervous system activity in SHRSP. They also suggest that this sympatho-inhibitory effect may be mediated by an increase in NO production, with the upregulation of eNOS expression in the brain.     

大鼠主动脉球囊拉伤后一氧化氮合酶表达的变化

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Role of neuronal nitric oxide synthase and inducible nitric oxide synthase in intestinal injury in neonatal rats

AIM: To investigate the dynamic change and role of neuronal nitric oxide synthase (nNOS) and inducible nitric oxide synthase (iNOS) in neonatal rat with intestinal injury and to define whether necrotizing enterocolitis (NEC) is associated with the levels of nitric oxide synthase (NOS) in the mucosa of the affected intestine tissue. METHODS: Wistar rats less than 24 h in age received an intraperitoneal injection with 5 mg/kg lipopolysaccharide (IPS). Ileum tissues were collected at 1, 3, 6, 12 and 24 h following LPS challenge for histological evaluation of NEC and for measurements of nNOS and iNOS. The correlation between the degree of intestinal injury and levels of NOS was determined. RESULTS: The LPS-injected pups showed a significant increase in injury scores versus the control. The expression of nNOS protein and mRNA was diminished after LPS injection. There was a negative significant correlation between the nNOS protein and the grade of median intestinal injury within 24 h. The expression of iNOS protein and mRNA was significantly increased in the peak of intestinal injury. CONCLUSION: nNOS and iNOS play different roles in LPS-induced intestinal injury. Caution should be exerted concerning potential therapeutic uses of NOS inhibitors in NEC.     

Endothelial,but not the inducible,nitric oxide synthase is detectable in normal and portal hypertensive rats

BACKGROUND: Chronic portal hypertension is accompanied by a nitric oxide (NO) dependent vasodilation. Three isoforms of NO producing synthases (NOS) are characterized: neuronal NOS (nNOS), endothelial NOS (eNOS) and inducible NOS (iNOS). Sources of increased NO levels in chronic hypertension is disputed. METHODS: To determine eNOS and iNOS expression in different organs of portal hypertensive and control rats, we divided Sprague-Dawley rats in 6 groups: (1). Partial portal vein ligated rats, (2). Bile duct ligated rats, (3). Carbon tetrachloride treated rats, (4). Sham operated rats, (5). Untreated control rats, and (6). LPS treated rats. Immunohistochemistry (IHC) and immunoblotting (IB) using antibodies against eNOS or iNOS were carried out on samples from thymus, aorta, heart, lung, oesophagus, liver, spleen, kidney, pancreas, small and large intestine. RESULTS: IHC revealed an even eNOS expression in all groups. Expression of iNOS was restricted to macrophages in organs of LPS treated and the thymus of rats. IB mirrored these results. CONCLUSION: In chronic portal hypertension, the main source for NO production depends on eNOS activity.