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.     

Renin-angiotensin and endothelial nitric oxide synthase gene polymorphisms are not associated with the risk of incident type 2 diabetes mellitus: a prospective cohort study

Objective. The renin–angiotensin system and endothelial function have both been implicated in the pathogenesis of type 2 diabetes. The aim of this study was to assess the relationship between a set of well‐characterized genetic variants of the renin–angiotensin system and the endothelial nitric oxide synthase (NOS3) gene and the incidence of type 2 diabetes. Design. Prospective cohort study. Setting. Women’s Health Study, United States. Subjects. A total of 24 309 Caucasian women free of diabetes at baseline. Main outcome measures. Six previously characterized single nucleotide polymorphisms (NOS3 rs1800779, NOS3 rs3918226, NOS3 rs1799983, ACE rs1799752, AGT rs699 and AGTR rs5186) were genotyped. Cox proportional‐hazards models were constructed to compare the incidence of type 2 diabetes according to the different genotypes. Results. During a median follow‐up of 10.2 years (interquartile range 9.6–10.6 years), 999 women developed type 2 diabetes. The age‐adjusted incidence rates across the six genotypes were very similar, and ranged from 3.7 to 4.8 cases/1000 person‐years of follow‐up. The multivariable adjusted hazard ratios (95% confidence intervals) for rs1800779, rs3918226, rs1799983, rs1799752, rs699, and rs5186 were 1.01 (0.92–1.10), 1.09 (0.93–1.27), 0.95 (0.86–1.05), 1.04 (0.95–1.14), 1.08 (0.98–1.18), 1.01 (0.91–1.11), confirming the lack of association between the genotypes and incident type 2 diabetes. Stratification by body mass index revealed essentially unchanged results. Finally, there was no association between NOS3‐haplotypes and incident type 2 diabetes. Conclusion. We did not find an association between six well‐characterized genetic polymorphisms of the renin–angiotensin system or the NOS3 gene and the occurrence of type 2 diabetes.     

肝癌组织中一氧化氮合酶及其基因表达的研究

目的研究肝癌组织中一氧化氮合酶(iNOS)及其基因表达与肝癌发生发展的关系。方法用免疫组化和原位杂交的方法对21例肝癌及癌旁组织中的诱导型一氯化氮合酶(iNOS)及其基因表达进行原位检测和观察。结果:NOS 阳性反应物质呈黄色或棕黄色,位于细胞浆中。非癌殖织(肉眼观距癌组织边缘>1.5)多呈阴性或弥漫弱阳性,但部分非癌组织中可见 iNOS 呈阳性的细胞呈点状分布;癌旁组织多呈阳性,提示 iNOS 表达与肝组织癌变有关。癌组织核心多呈阴性或弥漫弱阳性,但分化中和差的癌组织核心也分别有一例 NOS 呈强阳性;周边癌组织呈局灶阳性,侵入纤维组织中的弥敢癌细胞星强阳性,提示 NOS 的表达与肝癌组织的侵润能力有关。肝癌组织 iNOSmRNA 阳性细胞的分布与 iN-OS 蛋白的表达基本相似。结论 iNOS 蛋白及其基因表达与肝组织癌变及肝癌侵润能力有关。     

人胃癌组织中一氧化氮合酶的表达

目的探讨NOS与胃癌的关系.方法用NADPH-d组织化学法测定了正常胃组织、癌旁组织和癌组织中一氧化氮合酶(NOS)表达水平.结果正常胃组织中粘膜上皮细胞、各种有分泌功能的细胞及肌层神经纤维中均有NOS表达,测一个视野NOS阳性细胞的平均灰度,正常胃组织为112、癌旁组织为120、胃癌组织为145.各组间差异有显著意义.表明正常胃组织NOS活性最高,胃癌组织NOS活性最低.结论①正常胃组织有广泛的NOS分布,提示NO对维持正常胃功能具有重要作用;②胃粘膜细胞癌变过程中,NOS活性明显降低,提示NOS活性与胃粘膜细胞癌变有高度相关性.     

内皮型一氧化氮合酶基因多态性与急性心肌梗死的相关性探讨

目的　探讨内皮型一氧化氮合酶 (eNOS)基因多态性与急性心肌梗死 (AMI)的相关性。方法　依据eNOS基因外显子 7G894T位点设计引物 ,通过巢式聚合酶链反应 (PCR)扩增目的片段 ,限制性内切酶消化目的片段 ,琼脂糖凝胶电泳 ,紫外透射分析仪检测 ,计数 10 7例AMI病人及 81例健康者基因型及突变基因频率 ,通过χ2 检验有无统计学意义。结果　eNOS基因外显子 7的 894位点有 3种基因型 :GG、GT、TT。AMI组 10 7例中2 5例发生G894T突变 ,纯合子TT 9例 ,杂合子GT 16例。对照组 81例中 13例发生G894T突变 ,均为杂合子。两组等位基因纯合子突变具有非常显著统计学意义 ,x2 =5 4 2 9,P <0 0 5 ,两组等位基因总突变率 (纯合子 +杂合子 )无明显统计学意义 ,x2 =1 5 2 9,P >0 0 5。结论　eNOS基因 894位点TT型突变与AMI发病密切相关 ,是AMI发病的危险因子     

Expression of inducible nitric oxide synthase in human gastric cancer

INTRODUCTIONInduciblenitricoxidesynthase(iNOS)isanenzymethatcatalyzestheformationofnitric0xide(N0)fromL-arginine.iNOSexpressionandactivityresultsintheproduction0fhighlevelsofNO[1].ThegenerationofphysiologicallevelsofNOisimp0rtantformucosalfunctionanditalsoexertsacytoprotectiveeffectonthegastr0intestinalmucosa.However,increasediNOSexpressionhasbeenobservedinpatientswithchronicinflammatorydiseasesofthegastr0intestinaltract,suchasulcerativec0litis[2'3],andgastritis['Jandithasbeenspecul…     

内皮型一氧化氮合酶基因多态性与冠心病的关系

内皮型一氧化氮合酶(eNOS)基因被列为冠心病(CHD)的一个候选易感基因。本文对与冠心病关系较为密切的三种eNOS基因多态性:4b/a、T786C和G894T的研究进展作一综述,对进一步认识冠心病的发病机制具有重要意义。     

Subcellular distribution of nitric oxide synthase isoforms in the rat duodenum

AIM:To study the cell-type specific subcellular distribution of the three isoforms of nitric oxide synthase(NOS) in the rat duodenum.METHODS:Postembedding immunoelectronmicroscopy was performed,in which primary antibodies for neuronal NOS(nNOS),endothelial NOS(eNOS),and inducible NOS(iNOS),were visualized with protein A-gold-conjugated secondary antibodies.Stained ultrathin sections were examined and photographed with a Philips CM10 electron microscope equipped with a MEGAVIEW II camera.The specificity of t...     

内皮型一氧化氮合酶基因多态性与冠心病的研究进展

冠状动脉粥样硬化性心脏病（cronary atherosclerotic heart disease,CHD）简称冠心病,是指冠状动脉发生粥样硬化引起管腔狭窄或闭塞,导致心肌缺血缺氧或坏死引起的心脏病.吸烟、肥胖、高血压及代谢综合征等均已成为广为人知的几个冠心病重要危险因素.但也有患者没有这些危险因素存在,并且在一些个体中,常有明显的冠心病家族史,说明冠心病是环境与遗传危险因素动态相互作用所致的.目前已有诸多冠心病基因多态性研究,包括内皮型一氧化氮合酶（endothelial nitric oxide synthase,eNOS）.在近年的荟萃分析中显示,某些遗传变异可能为特定群体冠心病发病的危险因素之一.     

NO及NOS在低氧大鼠肺组织和主动脉中的差异性及其意义

目的观察低氧性肺动脉高压大鼠肺组织匀浆、主动脉匀浆及出肺血和入肺血中一氧化氮（NO）的含量、一氧化氮合酶（NOS）的活性。方法将24只雄性SD大鼠随机分成4组,即常氧2周组、常氧3周组、低氧2周组、低氧3周组。采用间断负压低氧法制备大鼠低氧性肺动脉高压模型;右心室导管法测定最高肺动脉压（PAP）;左颈总动脉插管测量左颈总动脉压代表动脉血压（Psa）;计算右心室肥厚指数[RV/（LV+S）];采用硝酸还原酶法测定各组大鼠出、入肺血及肺组织和主动脉匀浆中的NO含量;用化学比色法测定各组大鼠肺组织和主动脉匀浆中NOS的活性;应用免疫组化染色法观察各组大鼠肺组织及主动脉eNOS在蛋白质水平表达的变化。结果低氧组大鼠的PAP[（43.4±4.4）mmHg,（51.8±4.2）mmHg,1mmHg=0.133kPa],RV/（LV+S）（32.3±1.0,37.0±1.6）均高于其正常对照组[（20.8±2.4）mmHg,（21.8±3.9）mmHg;21.3±1.0,20.3±1.2,P<0.01)],且随缺氧时间延长而增高（P<0.01）,而Psa与常氧对照组比无差别。低氧组大鼠的出、入肺血及肺组织匀浆中的NO含量、NOS活性及肺组织eNOS的表达量均较其常氧对照组显著降低（P<0.01）,出肺血与入肺血的NO含量无差别;主动脉匀浆中NO含量和NOS的活性及大鼠主动脉的eNOS染色在各组间未见明显差异。结论低氧时,大鼠肺组织中NO的含量及NOS的活性均较常氧时降低,而主动脉中二者的表达在低氧和常氧时却没有差异,这种差异性可能是低氧时引起肺动脉高压却很少导致高血压的机制之一。     

Nitric oxide synthase gene polymorphisms and nephropathy in Asians with Type 2 diabetes

OBJECTIVE: Recent studies on Caucasians have reported an association between diabetic microvascular complications and polymorphisms in the inducible nitric oxide synthase (iNOS) gene. In view of the differences in the pattern of diabetic complications in Asians, we studied these iNOS polymorphisms in Asians with Type 2 diabetes who do and those who do not have nephropathy. METHODS: Two hundred fifty-eight Asians who have had Type 2 diabetes for at least 10 years, with overt nephropathy or with normoalbuminuria, were genotyped for the (AAAT)(n) and (CCTTT)(n) polymorphisms in the promoter region of the iNOS gene. A subanalysis was made of the findings from the three ethnic groups (Chinese, Malays, and Indians). RESULTS: The (AAAT)(3) polymorphism, which is the most common allele in Caucasians, was completely absent in our entire cohort of 258 Asian diabetics. The (AAAT)(4) polymorphism was the commonest, with a frequency of 0.984 as compared with 0.2 in Caucasians. We also found previously unreported alleles: (AAAT)(5) in 6 patients and (AAAT)(6) in 1 patient. There was no statistically significant association with nephropathy, in view of the highly skewed distribution of the alleles. However, the higher repeats (AAAT)(5) and (AAAT)(6) were found in the patients with a very rapid onset of severe nephropathy. The (CCTTT)(n) polymorphism also showed significant differences in allele distribution between the Asian and the Caucasian and African populations (P=.001). However, there was also no significant association with nephropathy and no significant difference in the ethnic distribution of alleles. CONCLUSIONS: We have identified significant differences in the (AAAT)(n) and (CCTTT)(n) polymorphisms in Asian diabetics. We have shown that there are significant differences in the overall allele distribution between the Asian and the Caucasian and African populations. However, our study did not demonstrate an association between iNOS gene polymorphisms and diabetic nephropathy.     

Inducible nitric oxide synthase expression in chronic viral hepatitis and its relation with histological severity of disease

summary . The role of nitric oxide in the pathogenesis of chronic viral hepatitis is not known. Elevated nitric oxide production is assumed to be responsible for the pathological changes in many inflammatory conditions, mainly via peroxynitrite, a potential oxidant that is produced by the reduction of superoxide anion with nitric oxide. The intensity and the distribution of the immunohistochemical staining of intrahepatic inducible nitric oxide synthase were studied in the biopsy specimens obtained from 63 patients with viral hepatitis and 13 patients with elevated transaminase levels of various aetiologies. Hepatic inducible nitric oxide synthase staining was significantly more intense in the viral hepatitis group ( P  = 0.000). Inducible nitric oxide synthase staining levels correlated well with the severity of the viral hepatitis using the Knodell's liver histological activity index ( r  = 0.393, P  = 0.002) Among the viral hepatitis group, the pathological distribution of the inducible nitric oxide synthase staining favoured the periportal hepatocytes (zone 1) whereas less staining was observed in parenchymal hepatocytes zone of 2 and 3 and bile duct epithelium. As nitric oxide mediated nitration of hepatocellular proteins is elevated in inflamed hepatic tissues and is correlated with the severity of the disease, we suggest that inducible nitric oxide synthase can possibly have a critical role in the pathogenesis of chronic viral hepatitis.     

Blood pressure response to hypoxia: role of nitric oxide synthase

BACKGROUND: Chronic exposure to hypobaric hypoxia has been shown to increase arterial pressure in genetically normal rats. The associated increase in blood pressure is unrelated to the hypoxia-induced erythrocytosis and persists indefinitely after restoration of normoxia. It is accompanied by a marked reduction in urinary excretion of nitric oxide metabolites (NOx) and is ameliorated by L-arginine supplementation. In view of the latter observations, we hypothesized that hypoxia-induced hypertension may be associated with downregulation of NO synthase (NOS). METHODS: Male Sprague Dawley rats were randomized to the hypoxic and control groups. Rats assigned to the hypoxic group were placed in chambers with air pressure maintained at 390 mm Hg. Animals assigned to the control group were kept in the chamber at 760 mm Hg air pressure. Animals were kept in their respective conditions for up to 21 days. Group of animals were tested at days 2, 3, 7, and 21. RESULTS: The hypoxic group exhibited a steady increase in arterial pressure beginning at day 3. This was accompanied by a transient increase followed by a significant decline in kidney NOS-I, NOS-II, and NOS-III abundance. A similar biphasic change was observed with NOS-II and NOS-III in the cardiac and vascular tissues. The changes in NOS abundance in the given tissues were associated with parallel changes in nitrotyrosine abundance, which reflects local NO production. The latter finding provides functional evidence for the changes observed in NOS abundance. CONCLUSIONS: Chronic hypoxia-induced hypertension in rats is associated with marked downregulation of NOS isotypes, which can, in part, account for the previously reported L-arginine-responsive hypertension in this model.     

An additive effect of endothelial nitric oxide synthase gene polymorphisms contributes to the severity of atherosclerosis in patients on dialysis

BACKGROUND: Reduced synthesis of nitric oxide (NO) is considered a major proatherogenic mechanism in patients with end-stage renal disease (ESRD), but genetic factors impinging on this mechanism have been little studied in this population. METHODS: We tested the relationship between carotid intima-media thickness (IMT) and three endothelial NO synthase (eNOS) polymorphisms (G894T, T-786C, and 27-bp repeat in intron 4) in an ethnically and geographically homogeneous group of 147 patients with ESRD. RESULTS: The IMT was significantly thicker (P = .01) in patients with the TT genotype (G894T polymorphism) than in patients with TG or GG genotypes, and a similar association was observed for the T-786C polymorphism (P = .02). These relationships remained statistically significant (P = .02 and .01), also in multivariate models including traditional and emerging risk factors for atherosclerosis. Moreover, there was a direct association between the number of risk alleles and IMT (no risk allele: 0.97 +/- 0.22 mm, 1 risk allele: 1.03 +/- 0.20 mm, 2 risk alleles: 1.07 +/- 0.22 mm, > or =3 risk alleles: 1.23 +/- 0.36 mm, P < .001) that remained statistically significant in a multiple regression model. CONCLUSIONS: In patients on dialysis the risk alleles of G894T and T-786C polymorphisms of the eNOS gene are associated with carotid atherosclerosis. The additive effect of the two polymorphisms may contribute to the severity of atherosclerosis independently of other risk factors and of endogenous substances that influence the NO synthesis in this population.     

内皮型一氧化氮合酶基因4b/a和T786C多态性与颈动脉粥样硬化的关联分析

目的:在汉族老年群体中探讨内皮型一氧化氮合酶(eNOS)基因4b/a和T786C多态性与颈动脉粥样硬化(CAS)的关联性。方法:选择接受颈动脉超声检查的汉族老年患者521例,根据超声检查结果分为CAS组266例和对照组255例。分别用PCR和PCR-RFLP方法分析4b/a和T786C多态性的基因型,同时对所有对象检验血脂等危险因素。结果:两个多态性处于连锁不平衡(LD)。两个多态性的基因型和等位基因分布在CAS组和对照组间均差异无统计学意义(均P>0.05)。在调整性别和年龄等多个CAS常见危险因素的前后,两个多态性各基因型与CAS的关联均差异无统计学意义(均P>0.05)。单体型分析发现,对常见危险因素进行调整后,单体型4a-T与CAS的关联差异有统计学意义(OR=2.86,95%CI=1.11～7.40,P=0.030)。结论:在所研究的汉族老年人群中未发现eNOS基因4b/a或T786C多态性单独与CAS相关联,但二者构成的单体型4a-T可能是汉族老年群体发生CAS的独立易感遗传标记。     

应激对大鼠结肠神经系统nNOS表达的影响

目的:探讨应激对大鼠结肠神经系统nNOS表达的影响. 方法:SD大鼠30只随机分为对照组,应激组和L-NAME 组,采用水浸-束缚应激(WRS)动物模型,用免疫组织化学ABC法检测nNOS在大鼠结肠黏膜下神经丛和肌间神经丛的表达,应用计算机图像分析系统对其表达进行定量分析．结果:与对照组比较,应激组黏膜下神经丛和肌间神经丛的nNOS阳性神经元的灰度值明显减少(P=0．02或P =0．005),阳性神经元细胞数的平均密度增加(P=0．04 或P=0．01),表达增强,且在黏膜上皮细胞、固有层淋巴细胞也有nNOS表达．L-NAME组黏膜下神经丛和肌间神经丛的nNOS阳性神经元的灰度值较应激组增加 (P=0．04),平均密度下降(P=0．04或P=0．03),表达减弱,而与对照组比较均无明显差异(P>0．05)．结论:应激可引起大鼠结肠神经系统nNOS表达增强, 提示一氧化氮(NO)在应激所致的结肠功能失调中可能起重要作用．     

复方灯盏花滴丸对海马神经元一氧化氮和一氧化氮合酶的影响

目的研究复方灯盏花滴丸(FDD)对谷氨酸致大鼠原代海马神经元的NO和一氧化氮合酶的影响。方法取SD大鼠32只,每8只分别用生理盐水、尼莫地平、FDD高、低剂量灌胃,85h后,取每只大鼠股动脉血,制成5%的含药血清。另取新生24h SD乳鼠大脑原代培养海马神经元并鉴定后,随机分为对照组、尼莫地平组、FDD高、低剂量组和模型组,前4组分别加入上述配制对应的药物血清,模型组不加含药血清。以谷氨酸制成损伤模型。采用MTT法测定细胞存活率,酶法检测细胞释放NO量,细胞内总一氧化氮合酶(tNOS)和诱导型一氧化氮合酶(iNOS)活性。结果与对照组比较,模型组细胞存活率下降,NO、tNOS和iNOS活性增加(P0.01),与模型组比较,FDD高、低剂量组均能明显增加细胞存活率、减少NO释放、降低tNOS活性和iNOS活性(P0.05,P0.01)。结论 FDD对谷氨酸致原代培养大鼠海马神经元损伤有保护作用,其作用机制可能与降低一氧化氮合酶的活性、尤其iNOS活性及减少NO释放有关。