大鼠肝缺血／再灌注后肝组织一氧化氮和不同亚型一氧化氮合酶的变化

目的探讨一氧化氮（NO）和一氧化氮合成酶（NOS）在肝缺血／再灌注（I／R）过程中的变化和作用。方法健康雄性SD大鼠24只，随机分为3组（每组8只）：①正常对照组，术中只分离肝周围韧带，不做肝门阻断及再灌注。②I/R组，进行45min的部分肝门阻断及60min的再灌注。③L-精氨酸（L—Arg）组，缺血前20min经阴茎背静脉注射L—Arg（300mg／kg），余同②组。实验结束后，取下腔静脉血2ml，并迅速切取缺血肝组织。检测血清丙氨酸转氨酶（ALT）、门冬氨酸转氨酶（AST）、乳酸脱氢酶（LDH）；测定肝组织中超氧化物歧化酶（SOD）、丙二醛（MDA）、黄嘌呤氧化酶（XOD）、一氧化氮（NO）和一氧化氯合成酶（NOS）等指标；观察光镜和电镜下肝组织学变化。结果与正常对照组相比，I／R组iNOS升高，NO降低；L-Arg组NO、eNOS均高于I／R组。2、3组比1组大鼠的肝组织病理损害重、肝功能差，L—Arg组病理损害较I／R组明显减轻、肝功能改善。结论NO对大鼠肝I／R损伤具有保护作用．不同亚型NOS的变化参与其中。     

内皮型一氧化氮合成酶基因Glu298Asp多态性与糖尿病肾脏病的关系

目的探讨内皮型一氧化氮合成酶（eNOS）基因Glu298Asp多态性与糖尿病肾脏病（DIcD）的关系。方法采用聚合酶链反应（PCR）后限制性内切酶消化技术,对在我院就诊的326例中国汉族2型糖尿病（T2DM）患者和215名健康体检者进行Glu298Asp基因型分析。根据尿白蛋白排泄率（UAER）水平将T2DM患者分为3组：UAER正常组（DM组）102例,微量白蛋白尿组（MAU组）81例,临床肾病组（DKD组）143例。选择同时期本院健康体检者215名为对照组。用多因素Logistic回归分析法判定DKD的独立危险因素。结果DKD组与对照组Glu298Asp基因型频率分布存在显著性差异（GG72．72％、GT26．57％、TT0．70％比GG83．41％、GT16．10％、TT0．49％,P=0．019）,而DM组和MAU组则与对照组无差异（P〉0．05）。Logistic回归分析显示,年龄、平均动脉压、GT基因型是DKD发生的独立危险因素。结论eNOS Glu298Asp基因与中国汉族T2DM患者DKD具有相关性。     

Expression of nitric oxide and inducible nitric oxide synthase in acute renal allograft rejection in the rat

BACKGROUND: Recent studies have shown that nitric oxide (NO) synthases, particularly inducible nitric oxide synthase (i-NOS), are induced in acute rejection episodes following heart, liver, pancreas and kidney allotransplantation. Furthermore, tissue and cellular injury has been demonstrated to be mediated by peroxynitrite (ONOO-), a metabolite of NO as well as a potent oxidant. However, a detailed relationship between NO, i-NOS and graft injury in transplantation remains elusive. METHODS: The present study used the following models of renal transplantation in rats: allografts (n = 5, Brown-Norway to Lewis [LEW] rats), isografts (n = 5, LEW to LEW) and allografts treated with aminoguanidine (AG), an i-NOS inhibitor (n = 5). Blood urea nitrogen (BUN), serum creatinine (SCr) and urinary and serum nitrosocompounds (NOx) were measured on days 2, 4 and 7 post-transplant. Western blot analysis of i-NOS protein expression and measurement of i-NOS activity were carried out in grafts harvested on Day 7, along with immunohistochemical and histopathological examinations. RESULTS: In the allograft group, both BUN and SCr levels increased markedly on Day 7, in parallel with a sharp increase in NOx. A band stained by anti-i-NOS antibody was detected at approximately 130 kDa, along with high levels of i-NOS activity and diffusely distributed i-NOS-positive cells (macrophages). Histologically, an acute rejection episode was confirmed (Grade 3 according to Banff classifications). In the AG group, reduced renal function and graft injury were significantly less severe than in the allograft group. CONCLUSIONS: In rat renal allograft acute rejection, markedly increased levels of serum NOx were observed, along with enhanced tissue i-NOS activity, together resulting in graft injury. AG administration suppressed the increase of serum NOx levels, with concomitant mitigation of tissue injury and renal function impairment.     

iNOS/NO对结直肠肿瘤发生发展的影响

一氧化氮（nitric oxide,NO）具有广泛的生物学活性。近年来发现一氧化氮（NO）、一氧化氮合成酶（nitric oxide synthase-2,NOS-2）与结直肠肿瘤的发生、发展密切相关,它与环氧化酶（cy-cloxygenase-2,COX-2）之间存在复杂的调控机制。对NO清除剂、NOS抑制剂和释放NO的非甾体抗炎药的研究为结直肠肿瘤的防治提供了一个思路。     

一氧化氮及一氧化氮合酶与吗啡耐受关系的新进展

疼痛治疗中长期给予吗啡易导致严重的耐受问题.多年来,针对耐受机制的研究表明NMDA/NO级联反应参与耐受的发生及发展.一氧化氮(nitric oxide,NO)主要是由一氧化氮合酶(nitric oxide synthase,NOS)催化其惟一前体--L-精氨酸生成NO和瓜氨酸.研究者们证实了大鼠鞘内吗啡耐受后脊髓内NOS尤其是nNOS的表达增高,耐受机制主要通过N-甲基-天门冬氨酸(N-methyL-D-aspartate,NMDA)受体的激活以及胞内钙离子浓度的升高来调节NOS的活性而触发NMDA/NO级联反应,继而影响耐受的发展.诸多研究给予吗啡的同时给予NOS抑制剂可以阻止耐受的发生,甚至在耐受形成后应用NOS抑制剂也可以翻转已经建立的耐受.但证实NOS各亚型在耐受中的具体作用仍不明确,需开展相关的研究进一步阐述其间的关系.     

Regulation of nitric oxide synthesis in uraemia

Nitric oxide (NO) is a cell-to-cell mediator involved in theregulation of vascular tone and in the mechanisms of host defence.Since uraemic syndrome is characterized by abnormalities inblood pressure and flow and by impairment of white cell function,we studied the regulation of nitric oxide synthase (NOS) activityby uraemic plasma. We used three different cellular types havingdifferent levels of NOS activity: tEnd. 1 murine endothelialcell line transformed by mT oncogene of polyomavirus had a highNOS activityand expressed endothelial-NOS (eNOS) and inducible-NOS(iNOS) isoforms; human endothelial cells from cord umbilicalvein (HUVEC) had low enzymatic activity and expressed only eNOS;finally, J774 murine macrophage line was characterised by iNOSinduced after treatment with cytokines. We demonstrated thatmost (79%) of end-stage uraemic plasma studied inhibited NOSactivity in tEnd.1 and in cytokine induced -J774, whereas theywere ineffective on HUVEC. Twenty percent of plasma samples(14 of 67) activated NOS activity in tEnd.1 and in J774 cells,but not in HUVEC, suggesting the presence of molecule(s) whichinfluence iNOS. The effect of plasma was not dependent on thetype of haemodialysis treatment. A great number of plasmas frompatients with moderate renal failure also inhibited NOS activityin tEnd.1, suggesting that the accumulation of molecules affectingNOS was caused by the renal failure rather than the haemodialytictreatment. However, the haemodialysis modified the effect of plasmas onNOS activity. Plasma taken after haemodialysis session showeda reduced inhibitory activity in tEnd.1 and in some cases itenhanced NOS activity. Simultaneously, molecules reducing NOSactivity accumulated in the ultrafiltrate. The plasma concentrationof N^G-N^G dimethyl-L-arginine (asymmetrical dimethylarginine,ADMA), an inhibitor of NOS, increased in end-stage uraemic patientsand was reduced by haemodialysis. However, the concentrationsreached in uraemic plasmas were lower than the ADMA ICM₅₀ ontEnd.1 NOS, indicating that this compound contributes with othermolecules to the inhibitory effect of uraemic plasma. Haemodialysisreduced also the enhanced effect exerted by some plasmas onNOS in J774. Therefore, the effect of endstage uraemic plasmaon NOS activity derive from the balance between inhibitors andactivators.     

The effects of arginine and selective inducible nitric oxide synthase inhibitor on pathophysiology of sepsis in a CLP model

BACKGROUND: Sepsis is an arginine-deficient state and is associated with overproduction of nitric oxide (NO) by inducible nitric oxide synthase (iNOS). It has been indicated that low plasma levels of arginine are related to high mortality rates in sepsis. Arginine, however, is also known to be a precursor of NO. Therefore, administration of arginine in septic patients remains controversial. We examined the effects of co-administration of arginine and aminoguanidine, a selective iNOS inhibitor, on sepsis, using rat models. METHOD: Sepsis was induced in rats by cecal ligation and puncture (CLP). Effects of separate and combined administration of arginine and aminoguanidine were investigated by comparing plasma levels of arginine, expressions of heme oxygenase (HO)-1 and HO-2 in liver and lung, and nitrite + nitrate (NOx) excretion in urine, as well as neuroendocrine responses in urine in the early phase of sepsis. Seven-day survival rates were also examined. RESULTS: A combination of arginine and aminoguanidine recovered the plasma level of arginine at 6 h post-CLP, decreased expression of HO-1 in liver and lung at 24 h post-CLP, decreased urinary excretion of epinephrine, norepinephrine, dopamine, and 17-hydroxycorticosteroid in the first 24 h post-CLP, and increased 7-d survival. CONCLUSION: It is demonstrated that administration of arginine together with the selective iNOS inhibitor in the early phase of sepsis restores plasma arginine, reduces oxidative stress by probably maintaining NO derived from constitutive NOS, and attenuates neuroendocrine stress responses. This co-administration may be a beneficial treatment approach against sepsis.     

脑出血患者一氧化氮、一氧化氮合酶的变化及临床意义

目的 探讨一氧化氮(NO)、一氧化氮合酶(NOS)与脑出血的关系。方法 测定76例脑出血患者及66例健康人血浆NO、NOS含量，分析上述指标在出血后3个时期的变化以及与患者颅内血肿量、是否合并蛛网膜下腔出血和临床预后的关系。结果 与对照组相比，脑出血1～3d组NO、NOS含量明显高于4～7d组、14d组和对照组，NO、NOS变化与颅内血肿量和／或合并蛛网膜下腔出血有一定关系。结论 NO、NOS参与了脑出血病理生理过程，其变化对病情的预后有一定的意义。     

Layer-specific production of nitric oxide during cortical circuit formation in postnatal mouse brain

In the developing cerebral cortex, neuronal nitric oxide synthase (nNOS) is expressed abundantly, but temporarily. During the early postnatal stage, cortical neurons located in the multi-layered structure of the cortical plate start forming well-organized cortical circuits, but little is known about the molecular machinery for layer-specific circuit formation. To address the involvement of nitric oxide (NO), we utilized a new NO indicator (DAR-4M) and developed a protocol for the real-time imaging of NO produced in fresh cortical slices upon N-methyl-D-aspartic acid stimulation. At postnatal day 0 (P0), NO production was restricted to the deep layers (layers V and VI) of the somatosensory cortex where transient synapses are formed. At P10, the production of NO was expanded to layer IV where large numbers of thalamocortical axons form synapses. The pattern of NO production could correspond to active sites for synaptic formation. This study is the first clear demonstration of NO production in the postnatal mouse neocortex. The findings presented may reflect a function of NO in relation to the layer-specific development of neural circuits in the neocortex.     

Activity of nitric oxide synthase in mature and immature human spermatozoa

Nitric oxide (NO) is known to be involved in multiple signal transduction pathways of male germ cells, including sperm capacitation. In somatic cells, NO production was found to be part of apoptosis signalling. The aim of our study was to further clarify the role of NO in spermatozoa by investigation of NO synthase activity with regard to sperm maturity and sperm apoptosis signalling. Semen specimens from 19 healthy donors were subjected to density gradient centrifugation to separate the predominantly mature and immature sperm fraction. NO synthase activity was evaluated using diaminofluoresceine‐2‐diacetate by FACS. Apoptosis signalling was monitored by flowcytometric analyses of caspase‐3 (CP3) and integrity of the transmembrane mitochondrial potential (TMP). TUNEL assay was used to detect DNA fragmentations. Maturity of human spermatozoa was associated with increased NO synthase activity and inactivated apoptosis signalling (lower levels of disrupted TMP, active CP3 and DNA fragmentations, P < 0.05). Activation of apoptosis signalling was significantly negatively correlated to NO production, indicating a rather anti‐apoptotic effect of NO. This might underline the recently proposed role of NO in physiological sperm signal transduction, e.g. during capacitation.     

重症急性胰腺炎患者血和腹水一氧化氮的动态变化

目的　研究诱生型一氧化氮合酶 (iNOS)活性在重症急性胰腺炎 (SAP)患者中的变化。方法　动态观察 30例重症急性胰腺炎患者发病后血性腹水和外周血一氧化氮 (NO)代谢产物NO2 - /NO3- 的变化。逆转录 聚合酶链反应 (RT PCR)检测外周血单个核细胞iNOSmRNA的变化。结果　SAP患者血性腹水NO2 - /NO3- 含量为 (385 .0± 92 .3) μmol/L与对照组 (41 .3± 1 9.5)μmol/L比较显著升高 (P <0 .0 0 1 )。起病后第 1、7、1 4天外周血NO2 - /NO3- 含量分别为(1 38.8±30 .2 ) μmol/L、(1 2 6 .4± 35 .4) μmol/L和 (77.8± 37.1 ) μmol/L ,随病情好转逐渐下降(P <0 .0 1 )。外周血单个核细胞iNOSmRNA表达在病情严重时显著增强。结论　iNOS活性增强产生过量NO参与重症急性胰腺炎全身病理生理的改变     

Changes in the oxidant-antioxidant balance in the kidney of rats with nephrolithiasis induced by ethylene glycol

PURPOSE: We investigated the possible mechanism of increased free radicals, the role of antioxidant enzymes and their correlation with renal tubular damage in the kidney after feeding 0.75% ethylene glycol to male Wistar rats. MATERIALS AND METHODS: Rats were divided into 7 experimental groups according to the duration of ethylene glycol feeding (1, 3, 5, 7, 9, 21 or 42 days) and into age matched control groups. Chemiluminescence levels were examined in blood samples (renal artery and vein) and in the kidney. The activities of oxidase and antioxidant enzymes were measured in kidney homogenates. The nitroblue tetrazolium perfusion method and immunohistochemical stains with ED1 and CD45 were performed. Urinary levels of alpha and mu-glutathione S-transferase (GST) were also measured and expressed in gm. urinary creatinine. RESULTS: Chemiluminescence levels of renal venous blood samples were elevated on days 1, 3 and 7 (p <0.05), and those of the kidney were elevated only on days 3 and 42 (p <0.05) compared with controls. The infiltration of CD45 positive cells in the kidney increased on day 7 and a further increase in these positive cells was noted on day 21. Fused ED1 positive cells surrounding the calcium oxalate crystals and adjacent to the nitroblue tetrazolium positive area were found on day 42. Xanthine oxidase activity showed no significant change, whereas nicotinamide adenine dinucleotide dependent oxidase activity was higher on day 5 and nicotinamide adenine dinucleotide phosphate dependent activity was elevated in all experimental groups (p <0.05). The activities of catalase and manganese superoxide dismutase were elevated in the early stage. On day 42 almost all antioxidant enzyme activities were attenuated (p <0.05) except that of catalase. The urinary levels of alpha-GST were elevated from day 7 until day 42, whereas levels of mu-GST were elevated from day 3 until day 42 except day 5. CONCLUSIONS: The possible mechanism that causes free radical elevation in the kidney may be different in the course of nephrolithiasis after ethylene glycol treatment. Initially the systemic circulation may bring the toxic substance into the kidney and cause it to produce free radicals. In the late stage gradually infiltrating leukocytes and decreased antioxidant enzyme activities may cause the kidney to remain under excessive oxidative stress.     

Paradoxical increase in nitric oxide synthase activity in hypercholesterolaemic rats with impaired renal function and decreased activity of nitric oxide.

BACKGROUND: We have shown that acute exposure of oxidized low-density lipoprotein (OX-LDL) induces vasoconstriction in renal vessels and reduces glomerular filtration rate (GFR) in an isolated perfused rat kidney model by decreasing the activity of nitric oxide (NO). L-arginine has a protective role against OX-LDl-induced vasoconstriction. Micropuncture studies have demonstrated that short-term diet-induced hypercholesterolaemia is associated with decreased GFR and renal blood flow and increased glomerular capillary pressure. This may be mediated by decreased activity of NO. METHODS: Rats were made hypercholesterolaemic by supplementing the standard chow with 4% cholesterol and 1% sodium cholate. A group of rats on hypercholesterolaemic diet also received L-arginine in the drinking water. After 4 and 6 weeks, blood samples and 24-h urine samples were collected for the measurement of biochemical parameters. After 6 weeks, all rats were subjected to isolated perfusion of kidneys at a constant pressure of 100 mmHg. During isolated perfusion, the unused contralateral kidney was taken for morphological studies and for assessing the activity of nitric oxide synthase enzyme by beta-NADPH diaphorase histochemistry. RESULTS: Rats fed a high-cholesterol diet had LDL levels 3-6 times greater than the rats fed standard chow. Rats that received L-arginine in the drinking water had serum L-arginine levels 5-6 times greater than control rats. At 6 weeks, creatinine clearance was significantly lower in the rats on the high-cholesterol diet compared to the rats on standard chow and rats on high-cholesterol diet plus L-arginine. Twenty-four-hour urinary total nitrate and nitrite excretion in the hypercholesterolaemic rats was 1.5-2 times greater than that of control rats. Twenty-four-hour urinary cGMP excretion was significantly lower in the rats on a high-cholesterol diet, but in the rats on high-cholesterol diet and L-arginine, 24-h urinary cGMP excretion was not significantly different from that of control rats. During isolated perfusion of kidneys, renal perfusate flow was found to be significantly reduced in the kidneys taken from the rats on a high-fat diet compared to controls. L-arginine supplementation in the drinking water almost completely reversed the effect of a high-fat diet. Inulin clearance was also significantly reduced in kidneys on a high-fat diet in contrast to controls but not in kidneys on high fat-diet and L-arginine. Basal cGMP excretion in urine was significantly lower in the kidneys taken from the rats on a high-fat diet compared to controls. L-arginine supplementation restored the basal cGMP excretion in these kidneys. NO synthase (NOS) enzyme activity as assessed by NADPH diaphorase activity showed that kidney sections taken from the rats on a high-fat diet showed more intense staining, indicating increased activity compared to the kidney sections taken from the rats on a normal diet. CONCLUSION: Though activity of NO is diminished in hypercholesterolaemic rats with impaired renal function, there is a paradoxical increase in NO production and NOS activity. L-arginine reverses the effects of a high-fat diet.     

诱导型一氧化氮合成酶对同系大鼠移植肠运动功能的作用

目的 观察诱导型一氧化氮合成酶(iNOS)对同系原位全小肠移植术后早期移植肠运动功能的影响.方法 分为对照组、移植组、L-NIL治疗组,每组12只大鼠.对照组行十二指肠造瘘术,另两组均行同系原位全小肠移植及十二指肠造瘘术,术后分别给予生理盐水、L-N6-(1-亚氨乙基)-赖氨酸(L-NIL).于术后2 d,各组取6只获取肠段行病理组织学检查,观察炎性损伤程度,并采用RT-PCR和免疫组织化学方法检测iNOS mRNA及蛋白表达水平.各组另6只行小肠传输实验,观测小肠传输功能.结果 移植组呈明显炎性损伤改变,iNOS mRNA及蛋白表达水平(1.278±0.142)%,(56.33±5.16)%较对照组(0.066±0.016)%,(9.17±3.17%)上调(P＜0.01),较对照组小肠传输延迟(P＜0.01).L-NIL治疗组炎性损伤程度较移植组减轻,iNOS mRNA及蛋白表达水平(0.588±0.096)%,(26.17±4.14)%较移植组下调(P＜0.01),且小肠传输延迟有改善(P＜0.01).结论 iNOS在术后早期移植肠炎症损伤及其引发的肠运动功能障碍中可能起重要作用.     

Renal effects of inhaled nitric oxide in humans

We measured renal sodium and water excretion in five healthymale volunteers who inhaled nitric oxide. Urine volumes, urinarysodium and creatinine, and plasma sodium and creatinine weremeasured before, during and after a 2-h period inhaling nitricoxide (40 vpm in air). A control experiment, excluding the nitricoxide, was done on a separate day. Nitric oxide increased urinaryvolume (mean increase 85%, SEM 22%) and prevented a decreasein fractional excretion of sodium (32% SEM 8%) seen in the controlexperiments, without a detectable change in creatinine clearance.The results suggest the inhaled nitric oxide may alter tubularsalt and water resorbtion in humans. The mechanism for thisremains unclear. Br J Anaesth 2001; 86: 267–9     

Induced nitric oxide impairs relaxation but not contraction in endotoxin-exposed rat pulmonary arteries

BACKGROUND: Many patients with severe acute lung injury do not respond to nitric oxide (NO) inhalational therapy with alleviation of pulmonary arterial hypertension and hypoxemia, so this treatment remains controversial. MATERIALS AND METHODS.: We investigated in endotoxin-exposed Wistar rat pulmonary arteries whether endogenous NO alters contractile and relaxing responses, by electrochemical NO and isometric force measurements. RESULTS: Receptor-independent contraction was similar in control and endotoxin-exposed arteries, while thromboxane analogue (TxA)-dependent contraction was less in the latter. Neither non-selective NO synthase (NOS) inhibition by N(G)-nitro-l-arginine (l-NA) or selective inducible-NOS2 inhibition by aminoguanidine (AG) improved TxA-induced contraction in endotoxin-exposed arteries. Acetylcholine-induced relaxation was impaired in endotoxin-exposed pulmonary arteries, despite a comparable acetylcholine-induced NO release in control arteries. Additionally, NO solution-induced relaxation of endotoxin-exposed arteries was impaired, but could be improved by l-NA or AG. Application of a phosphodiesterase-insensitive cyclic guanosine monophosphate analogue induced similar relaxation in both control and endotoxin-exposed arteries. CONCLUSIONS: Endotoxin-associated NOS2-derived NO is thus associated with impaired NO-mediated relaxation, but does not underlie reduced receptor-mediated pulmonary contractile responses. An increased phosphodiesterase activity may underlie the former, so this route can be explored to replace or improve the effect of inhalational NO therapy in severe sepsis-induced acute lung injury in patients.     

Heterogeneity of the effects of combined nitric oxide synthase inhibition on organ perfusion in ovine sepsis

Introduction

Previous studies demonstrated beneficial effects of early neuronal nitric oxide synthase (nNOS) and subsequent inducible NOS (iNOS) inhibition on the development of multiple organ dysfunctions in septic sheep. However, the effects of NOS inhibition on regional blood flow remained undetermined. The current study was conducted to assess the effects of combined NOS inhibition on blood flow to various organs in an ovine sepsis model.

Methods

Eighteen adult, female sheep were randomly allocated to the following groups: (1) sham-injured, non-treated group, (2) injured (smoke inhalation and instillation of Pseudomonas aeruginosa into the lungs), non-treated group (control), and (3) injured, treated group (specific nNOS inhibition from 1 h to 12 h and iNOS inhibition from 12 h to 24 h post-injury). Fluorescent microspheres were injected at baseline and various time points post-injury. At the end of the 24-h experimental period, tissue from various organs was harvested.

Results

Blood flow to the ileum was significantly increased in the control group from 12 h to 24 h versus sham (P < 0.05). This increase was attenuated in the treatment group (P < 0.05). In contrast, blood flow to the pancreas was significantly increased in the treatment group after 12 h and 24 h versus both sham and control (P < 0.05). Blood flow to the spleen was significantly lower after 24 h in the control group versus sham and treatment (P < 0.05 both).

Conclusions

Combined NOS inhibition significantly influenced the pathologically altered organ perfusion during ovine sepsis. However, this treatment strategy showed heterogeneous effects on organ perfusion, perhaps dependent on the sepsis-related degree of NO production and ensuing changes in regional flow.     

诱导型一氧化氮合成酶在迟发性血管痉挛中的作用

目的　以大鼠迟发性脑血管痉挛模型为基础研究诱导型一氧化氮合成酶 (iNOS)在迟发性血管痉挛发展中的作用。方法　 3 2只雄性SD大鼠随机分为实验组和对照组 ,实验组枕大池二次注血诱导迟发性脑血管痉挛 ,对照组枕大池注射生理盐水。第 8天行脑血管造影 ,枕大池抽取脑脊液测一氧化氮 (NO)浓度。逆转录 聚合酶链反应 (RT PCR )法和免疫组织化学法测定并评价iNOSmRNA和蛋白质在基底动脉、大脑中动脉和皮质中的表达。结果　颅内动脉血管减影提示对照组颈内动脉颅内段、大脑中动脉 (MCA)明显变细 ,大脑中动脉中段直径 (MD)与镫骨动脉中段直径 (SD)之比衡量大脑中动脉的管径显示实验组MCA管径较对照组MCA管径减少 3 0 %。对照组脑脊液中NO浓度为 (11.70± 2 .62 ) μmol/L ,实验组脑脊液中NO的浓度为(5 5 .67± 12 .84)μmol/L。iNOSmRNA和蛋白质表达于基底动脉、大脑中动脉和皮质 ,其中基底动脉表达最强。 结论　iNOS作为迟发性脑血管痉挛发展中的关键因素参与血管壁的迟发性损伤。