急性脑梗死后血浆NO、NOS、ET含量的动态变化及尼莫地平对其影响

目的　观察急性脑梗死 (ACI)后血浆一氧化氮 (NO)、一氧化氮合成酶 (NOS)、内皮素 (ET)含量的动态变化 ,以及尼莫地平治疗后对其影响。方法　ACI患者 110例 ,随机分成尼莫地平组 (5 0例 ) (在常规治疗基础上用尼莫地平 )和常规治疗组 (6 0例 )。在发病后不同时点动态观察血浆NO、NOS、ET含量 ,并设 5 0例脑动脉硬化患者为对照组。结果　脑梗死后血浆ET含量显著升高 ,直至恢复期 ;NO、NOS先增高后下降 ;尼莫地平组和常规组比较ET有显著差异 (P <0 .0 1) ,NO、NOS差别不显著 (P >0 .0 5 )。结论　NO、NOS、ET参与并影响了ACI后复杂的病理生理过程 ;尼莫地平部分通过对ET含量的影响发挥其对脑梗死的治疗作用     

一氧化氮在新生鼠缺氧缺血性脑损伤中的变化及高压氧的治疗机制

目的 探讨围产期缺氧缺血引起新生鼠脑损伤后脑组织一氧化氮(NO)含量的变化,以及高压氧(HBO)干预治疗的机制.方法 结扎孕鼠双侧子宫动脉复制围产期缺氧缺血性脑损伤(HIBD)的动物模型,并于生后6h、24h、72h、7d断头取脑,测定NO含量变化及一氧化氮合酶(NOS)的表达,应用TUNEL染色观察细胞凋亡的变化,设立对照组及HBO干预组.结果 HIBD后NO水平有明显上升,NOS表达增强,随缺氧时间的延长而增强,并伴有凋亡细胞显著增加.HBO治疗后可降低脑组织NOS的表达及NO的水平,明显减轻了脑细胞的凋亡.结论 在HIBD时存在NO的过量生成,NO参与HIBD的病理过程,HBO保护损伤脑组织的治疗机制可能与抑制NO生成有关.

Abstract：

Objective To examine the dynamic variation of plasma nitric oxide (NO) level in newborn rats with hypoxic isehemie brain damage (HIBD) and their relation with hyperbaric oxygen (HBO) treatment. Methods To produce HIBD animal model by ligating the uterine arteries of pregnant rats. We detected the plasma NO level and nitric oxide synthetase (NOS) expression by radioimmunoassay and immunohistochemistry before operation and 6h, 24h, 72h,7d after HIBD and treatment with HBO. The pattern of neuronal cell death after HIBD was examined using TUNEL staining. Results Plasma NO level markedly elevated at 24h after HIBD, and NOS expression reached peak at 72h. The two parameters were significantly fell in the same groups treated with HBO. HBO also minimized eminently apoptosis of cerebral cells.Conclusions HIBD may be associated with the abnormal excretion of NO, and the mechanism of HBO treatment of newborn rats with HIBD may be associated with the reduction of plasma NO.     

高压氧对蛛网膜下腔出血后脑血管痉挛的影响

目的探讨高压氧（hyperbaric oxygen,HBO）对蛛网膜下腔出血（SAH）后迟发性脑血管痉挛的影响及机制。方法采用枕大池2次注血法建立迟发性脑血管痉挛模型,将60只模型动物随机等分为SAH组和SAH＋HBO组,用显微测量法测量基底动脉管径,比色法测定血清中一氧化氮（NO）及一氧化氮合酶（NOS）含量,原子吸收分光光度计测定脑组织中的Ca^2＋含量。结果模型制作成功后96h测量基底动脉直径,结果显示：经HBO治疗后,脑血管痉挛的程度明显缓解。SAH组NO、NOS含量在术后24h及96h均降低,而经HBO治疗后则增高。SAH组Ca^2＋含量在术后24h及96h增高,经HBO治疗后则降低。结论高压氧能够缓解SAH后脑血管痉挛程度,改善受损的脑功能。     

氯美噻唑对大鼠脑出血周边组织一氧化氮含量、一氧化氮合酶活性及细胞凋亡的干预作用

目的 研究氯美噻唑对大鼠脑出血周边组织一氧化氮(NO)含量、一氧化氮合酶(NOS)活性及细胞凋亡的影响.方法 Wistar大鼠112只,随机分为脑出血组和脑出血+氯美噻唑(CMZ)组,两组各分为(出血前和出血后4h、6h、12h、24h、72h、7d)7个时间点.利用化学方法测定大鼠脑出血周边组织NO含量、NOS活性;利用原位末端标记法测定出血周边组织中神经细胞的凋亡情况.结果 大鼠脑出血周边组织NO含量、诱导型一氧化氮合酶(iNOS)、一氧化氮合酶(NOS)4h开始升高(P<0.05),24h到7d显著升高(P<0.01),大约72h左右NO、iNOS、NOS达峰值.大鼠脑出血周边组织6h出现凋亡细胞,12h上升显著(P<0.01),3d凋亡细胞达峰值,与NO、iNOS、NOS峰值对应,7d时仍存在较多凋亡细胞.氯美噻唑干预后,NO含量、iNOS和NOS活性及凋亡细胞数量与脑出血组对应时间点比较显著下降(P<0.01).结论 大鼠脑出血周边组织NO含量增高,iNOS、NOS活性增强,脑出血周边组织神经细胞存在长时间凋亡,NO、iNOS可以促进其凋亡;氯美噻唑干预后NO含量降低,iNOS、NOS活性下降,减少大鼠脑出血周边组织神经细胞凋亡.     

急性一氧化碳中毒后迟发性脑病患者血清NO与NOS水平及其临床意义

目的 探讨血清一氧化氮(nitric oxide,NO)、一氧化氮合酶(nitric oxide synthsae,NOS)的水平及其动态变化与急性一氧化碳中毒后迟发性脑病(delayed encephalopathy after acute carbon monoxide poisoning,DEACMP)患者病情变化的关系.方法 应用比色法(colorimetric method)动态测定31例DEACMP患者血清NO及NOS水平,并与30例急性一氧化碳中毒(acute carbon monoxide poisoning,ACMP)后未发生迟发脑病患者和30 例正常对照进行比较.结果 DEACMP患者急性期血清NO及NOS水平[(62.67 ± 14.39)μmol/L,(27.68 ± 6.14)U/mL]明显高于正常对照组[(50.18 ± 9.95) μmol/L,(20.88 ± 6.32)U/mL] (均P ＜ 0.05),与ACMP组急性期[(62.00 ± 16.46)μmol/L,(28.13 ± 5.23)U/mL]比较无统计学差异(均P ＞ 0.05);DEACMP患者恢复期血清NO及NOS水平[(54.66 ± 11.73)μmol/L,(21.74 ± 5.88)U/mL]明显低于急性期(均P ＜ 0.05),与ACMP组随访期[(52.79 ± 11.22)μmol/L,(20.64 ± 5.92)U/mL]比较无统计学差异(均P ＞ 0.05).结论 NO-NOS系统参与了DEACMP的发病机制,NO-NOS水平变化与病情变化基本一致.     

急性脑出血并发全身炎症反应综合征致多器官功能障碍综合征患者血清一氧化氮、一氧化氮合酶的变化

目的　探讨急性脑出血并发全身炎症反应综合征(SIRS)致多器官功能障碍综合征(MODS)的可能机制及一氧化氮(NO)、一氧化氮合酶(NOS)在急性脑出血致MODS发生发展中的作用。方法　观察急性脑出血并发SIRS及导致MODS的发生率。应用硝酸还原酶法及比色法动态监测73例急性脑出血患者血清NO及NOS的水平,并以20名健康人为对照。结果　脑出血并发SIRS的发生率为47. 95% (35 /73),其中74. 29% (26 /35)导致MODS。73例患者血清NO及NOS水平均明显高于正常对照组,且随病情的加重呈上升的趋势(均P<0. 01);重型MODS组较轻型组、死亡MODS组较存活组差异有极显著性(均P<0 01)。结论脑出血并发SIRS是导致MODS的主要机制,NO、NOS参与了脑出血并发SIRS及导致MODS的病理生理过程,并可作为一客观指标判断脑出血的病情及预后。     

卡托普利上调缺血性脑卒中患者血小板一氧化氮合酶的实验和临床研究

目的　研究卡托普利对缺血性脑卒中患者血小板一氧化氮合酶 (NOS)的上调及临床应用。方法　测定急性缺血性脑卒中患者及健康体检者的血小板NOS及在体外加氧化低密度脂蛋白 (oxLDL)、卡托普利后血小板NOS的活性 ;检测患者服卡托普利前、服后 1个月及 3个月的血浆oxLDL、NOS、一氧化氮 (NO) ,血小板NOS、NO ,同时检查神经功能。结果　 (1)卒中组和对照组血小板加oxLDL后 ,NOS值均明显下降 (P <0 .0 1) ,卒中组下降更明显 ;(2 )两组血小板同时加卡托普利、oxLDL后 ,NOS值均明显升高 (P <0 .0 1) ,卒中组升高更明显 ;(3)两组血小板单纯加卡托普利后 ,其NOS值均明显升高 (P <0 .0 1) ,同样亦是卒中组升高更明显 ;(4 ) 4 0例缺血性脑卒中患者服用卡托普利后血浆oxLDL明显下降 ,血小板NOS、NO ,血浆NOS、NO明显增高 ,神经功能明显改善。结论　卡托普利有直接上调血小板NOS的作用 ,卡托普利通过提高血小板NOS活性的作用 ,可以改善内皮功能 ,防治脑卒中     

二硫化碳对大鼠海马一氧化氮合酶活力和基因表达的影响

目的:探讨二硫化碳(CS2)对大鼠海马一氧化氮合酶(NOS)活力和基因表达的影响。方法:以吸入染毒法制作不同浓度CS2中毒大鼠模型:染毒2个月后,用Morris水迷宫法检测实验大鼠的学习记忆功能;以NOS测定试剂盒测定大鼠海马NOS活力;以半定量逆转录一聚合酶链式反应(RT-PCR)法测定神经元型一氧化氮合酶(nNOS)mRNA 含量的变化。结果:Morris水迷宫测试显示染毒后大鼠平均逃逸潜伏期较对照组延长,差异有显著性;各CS2染毒组大鼠海马NOS活性降低,与对照组比较差异有显著性,随CS2浓度的增加NOS活性降低,各染毒组间比较差异有显著性差异;染毒后海马nNOS mRNA含量比对照组显著减少,与CS2浓度呈剂量依赖关系,差异有显著性意义。结论:CS2致大鼠海马NOS活力降低及nNOS mRNA含量减少可能是CS2干扰学习记忆功能的机制之一。     

髓鞘碱性蛋白对急性一氧化碳中毒大鼠最终结局的预测价值及地塞米松干预的作用

目的评估髓鞘碱性蛋白(MBP)对急性一氧化碳(CO)中毒大鼠最终结局的预测价值,并探讨不同剂量地塞米松对急性CO中毒大鼠最终结局的干预作用。方法将130只体质量180²80g、雄性Wistar大鼠随机分成3个实验组(每组n=40)和健康对照组(n=10),即CO中毒组(CO中毒组);CO中毒+10mg·Kg-1·d-1地塞米松组(DXM-10组);CO中毒+30mg·Kg-1·d-1地塞米松组(DXM-30组)和健康对照组(NC组)。观察各组大鼠在染毒后21d内的死亡例数,并在染毒后60min断尾取血检测各组大鼠血清中MBP值。结果中毒后所有大鼠呈现典型急性CO中毒表现。在观察的21d内,CO中毒组中共有15只大鼠死亡,DXM-10组11只,而DXM-30组4只,死亡率分别为37.50%、27.50%和10.00%。而NC组中无大鼠死亡。实验组中所有死亡大鼠与存活大鼠其平均MBP值相比差异有统计学意义(P<0.05)。结论 CO中毒后60min腹腔内注射10mg·Kg-1·d-1地塞米松可降低急性CO中毒大鼠的死亡率,30mg·Kg-1·d-1地塞米松可显著降低其死亡率。MBP对急性CO中毒大鼠的最终结局具有预测价值。     

一氧化氮合酶活性与抑郁症的相关性

目的通过对抑郁症患者一氧化氮合酶（NOS）活性进行检测，从而研究和探讨一氧化氮合酶、一氧化氮（NO）与抑郁症之间的关系。方法采用分光光度法检测抑郁症患者治疗前后的一氧化氮合酶NOS及其亚型（结构型cNOS、诱导型iNOS）的活性，并与正常对照组比较。结果抑郁症组的NOS、cNOS活性显著低于正常对照组；治疗组的NOS、cNOS活性高于抑郁症（无显著性），但治疗后缓解组的NOS、cNOS活性均显著高于治疗前。各组iNOS的活性无显著差异。结论抑郁症病人的NOS活性下降，而且主要是结构型cNOS活性下降，经治疗缓解后有所提高。因此，NOS和NO很有可能在抑郁症的发病过程中起着重要作用。     

The effect of hyperbaric oxygen on regional brain and spinal cord levels of nitric oxide metabolites in rat

Hyperbaric oxygen (HBO(2)) therapy is reported to be beneficial in transient brain ischemia. The present study was conducted to determine the influence of HBO(2) on metabolites of nitric oxide (NO) in brain and spinal cord of rats. Rats were exposed to room air (RA), normobaric air (NBA), normobaric oxygen (NBO(2)), hyperbaric air (HBA) or HBO(2), the last two conditions at 2.5ATA (atmosphere absolute) for 60 min. The results demonstrate that, compared to the NBA control, oxygen alone generally reduced tissue levels of NO(x)(-) (nitrite plus nitrate). On the other hand, 2.5ATA alone tended to have a slight, if any, effect on tissue levels of NO(x)(-). The combination of oxygen and pressure (i.e., HBO(2)) generally led to an increase in tissue levels of NO(x)(-). Based on these findings, it is concluded that HBO(2) appears to markedly increase NO function most notably in the corpus striatum, brainstem, cerebellum and spinal cord.     

Neuronal nitric oxide synthase expression in cerebellar mutant mice

Nitric oxide (NO) is a diffusible, multifunctional signaling molecule found in many areas of the brain. NO signaling is involved in a wide array of neurophysiological functions including synaptogenesis, modulation of neurotransmitter release, synaptic plasticity, central nervous system blood flow and cell death. NO synthase (NOS) activity regulates the production of NO and the cerebellum expresses high levels of nitric oxide synthase (NOS) in granule, stellate and basket cells. Cerebellar mutant mice provide excellent opportunities to study changes of NO/NOS concentrations and activities to gain a greater understanding of the roles of NO and NOS in cerebellar function. Here, we have reviewed the current understanding of the functional roles of NO and NOS in the cerebellum and present NO/NOS activities that have been described in various cerebellar mutant mice and NOS knockout mice. NO appears to exert neuroprotective effects at low to moderate concentrations, whereas NO becomes neurotoxic as the concentration increases. Excessive NO production can cause oxidative stress to neurons, ultimately impairing neuronal function and result in neuronal cell death. Based on their genetics and cerebellar histopathology, some of cerebellar mutant mice display similarities with human neurological conditions and may prove to be valuable models to study several human neurological disorders, such as autism and schizophrenia.     

海人酸致痫动物模型脑内一氧化氮,一氧化氮合酶的变化

目的探讨一氧化氮（ＮＯ）、一氧化氮合酶（ＮＯＳ）在癫痫发生中的作用及ＮＯＳ抑制剂的作用。方法采用海人酸致痫大鼠模型并应用ＮＯＳ抑制剂Ｌ－硝基精氨酸甲酯（Ｌ－ＮＡＭＥ）,分别在致痫后３０分钟、６０分钟取海马组织,匀浆后测定ＮＯ及ＮＯＳ水平。结果致痫３０分钟后海马ＮＯ含量显著升高,至６０分钟恢复正常;ＮＯＳ活性水平增高＞５０％;Ｌ－ＮＡＭＥ明显抑制大鼠的痫性发作,应用ＮＯＳ抑制剂组大鼠海马ＮＯ、ＮＯＳ含量明显下降。结论癫痫发作后脑内ＮＯ、ＮＯＳ活性增强,ＮＯＳ抑制剂通过抑制酶活性使ＮＯ生成降低,并完全抑制痫性发作。ＮＯＳ活性受抑制＞４８％即可产生明显效果。提示ＮＯ可能有内源性致痫作用。     

Inducible nitric oxide synthase is responsible for nitric oxide release from murine pituicytes

This study investigated whether pituicytes were able to produce and release nitric oxide (NO), and which type of nitric oxide synthase (NOS) would be responsible for this phenomenon. Lipopolysaccharide (LPS) 1 micro g/ml was used as inflammatory mediator. Because pituicytes are known to secrete interleukin (IL)-6 upon stimulation with LPS, this parameter was also investigated. Cultured pituicytes, from 4-week-old male mice, were stimulated with LPS for 6 h or 24 h. At 24 h, there was a significant increase in accumulated nitrite indicating NO formation. In contrast, IL-6 release was already significantly higher 6 h after stimulation and further increased at 24 h. The correlation between accumulated nitrite and secreted IL-6 was 0.84 after 24 h of incubation with LPS. The expression of inducible NOS (iNOS) mRNA in the pituicytes was significantly higher than the control level after 6 h and 24 h of exposure to LPS, with levels at 6 h being significantly higher than those at 24 h. There was no detected expression of endothelial NOS or neuronal NOS mRNA. Cultured pituicytes were also subjected to immunocytochemistry for iNOS protein at 6, 12, and 24 h after stimulation with LPS. Most cells were positive for iNOS, but there were no observable differences with the time points that we used. Collectively, these results show that pituicytes are able to produce NO, and that the inducible form of NOS is responsible for this production. Furthermore, there is a weak correlation between NO and IL-6 released from pituicytes after 24 h of stimulation with LPS.     

Increased nitric oxide levels and nitric oxide synthase isoform expression in the cerebellum of the taiep rat during its severe demyelination stage

We have previously reported progressive reactive astrocytes in the cerebellum of taiep rats, one of the most regions affected by demyelination, and activation of cerebellar glial cells in vitro. Based on the hypothesis that activated glial cells produce high levels of reactive nitrogen intermediates, we assessed the production of nitric oxide (NO) and the expression of the three NO synthases (NOS) in the cerebellum of 6-month-old taiep rats. A significant 40% increase of NO levels was measured in taiep rats when compared with controls. The protein and mRNA levels of the three NOS isoforms were also significantly increased. In contrast to controls, immunostaining assays against nNOS or iNOS showed an increased number of immunoreactive glial cells in the granular layer (nNOS) and Purkinje layer (iNOS) of cerebellum of taiep rats. Microglia-macrophages and both CD4- and CD8-immunoreactive cells were observed in cerebellar white matter of taiep rats only, thus suggesting other possible cell sources of those NOSs. Differences in the cellular location for eNOS immunoreactivity were not observed. The enhanced levels of NO, NOS proteins, mRNAs, and NOS immunoreactivities in glial cells and microglia strongly suggest glial activation together with the professional immune cells can aggravate the demyelination of aged taiep rats.     

Glucose deprivation decreases nitric oxide production via NADPH depletion in immunostimulated rat primary astrocytes

We have previously reported that the production of nitric oxide (NO) in immunostimulated astrocytes was markedly decreased under glucose-deprived conditions. The present study was undertaken to find the contributing factor(s) for the decreased NO production in glucose-deprived immunostimulated astrocytes. NO production in rat primary astrocytes was stimulated for 24-48 h by cotreatment with lipopolysaccharides (1 microg/ml) and interferon-gamma (100 U/ml). Decreased NO production in immunostimulated astrocytes by glucose deprivation was mimicked by the glycolytic inhibitor 2-deoxyglucose and reversed by addition of pyruvate and lactate. Glucose deprivation did not alter the expression of inducible nitric oxide synthase (iNOS) in immunostimulated astrocytes. Addition of beta-NADPH, but not tetrahydrobiopterine, both of which are essential cofactors for NOS function, completely restored the NO production that was decreased in glucose-deprived immunostimulated astrocytes. Glucose deprivation and immunostimulation synergistically reduced intracellular NADPH level in astrocytes. The results indicate that glucose deprivation decreases NO production in immunostimulated astrocytes by depleting intracellular NADPH, a cofactor of iNOS.     

Developmental effects of in vivo and in vitro inhibition of nitric oxide synthase in neurons

The diffusible chemical messenger nitric oxide (NO) is involved in neuronal plasticity and it is, therefore, supposed to play a role in brain development. A shortage of NO during the critical period of brain maturation may theoretically have long-lasting consequences on the organization of the adult brain. We have performed in neonatal rats a chronic inhibition of the enzyme responsible for NO production, nitric oxide synthase (NOS), from postnatal day 3 to postnatal day 23, through administration of the competitive antagonist N-nitro-L-arginine methylester (L-NAME). The calcium-dependent catalytic activity resulted almost completely inhibited throughout the period of treatment and it took more than 4 days after its suspension to get a full recovery. The expression of the neuronal isoform of the enzyme (nNOS), revealed by immunoblotting, was unchanged during the treatment and after it. The histochemical reaction for NADPH diaphorase was reduced at the end of the treatment and recovered in concomitance with the recovery of the catalytic NOS activity. No gross structural alterations were detected in brain morphology. The levels of three neurotransmitter-related and one astrocytic marker were unchanged in the cerebellum, hippocampus and cortex of 60-day-old rats which had been neonatally treated. A similar lack of significant effects on neurochemical brain maturation was also noticed in a parallel series of experiments, in which a short pulse of NOS inhibition was performed at a critical prenatal time of brain development, from gestational day 14 to gestational day 19. In vitro, chronic exposure of cerebellar granule cells to L-NAME (500 microM) resulted in slight decrease of surviving neurons after 8 days in culture and in better resistance to the challenge of stressful culture conditions. The present results suggest that the basic plan of brain organization can be achieved despite an almost complete NOS inhibition during the maturation period. In vitro, NOS inhibition may bring to more pronounced consequences on neuronal viability and function.     

一氧化氮和一氧化氮合酶在鼠脑内形成吗啡依赖的作用研究

目的：研究一氧化氮（NO）和一氧化氮合酶（NOS）在吗啡依赖形成中的作用。方法;对吗啡依赖和戒断大鼠脑内NO含量和NOS活力进行测定。结果：未发现吗啡依赖和戒断大鼠脑内NO含量和NOS活力有改变。结论：对NO／NOS与吗啡依赖的关系还有待进一步研究。     

Agmatine inhibits matrix metalloproteinase-9 via endothelial nitric oxide synthase in cerebral endothelial cells

OBJECTIVES: Matrix metalloproteinases (MMPs) are up-regulated by ischemic injury and degrade the basement membrane of brain vessels to promote cell death and tissue injury. We previously showed that agmatine has a neuroprotective effect on neurons against ischemic injury. In the present study, we investigated the effect of agmatine on the expression of MMPs and nitric oxide (NO) production in cerebral endothelial cells (CECs) after oxygen-glucose deprivation (OGD)-reperfusion injury and its potential association with endothelial nitric oxide synthase (eNOS). METHODS: Primary cultured endothelial cells from murine brain and bEnd.3 cells were subjected to OGD-reperfusion injury. Protein and mRNA levels of both MMP-2 and MMP-9 were determined by immunocytochemical analysis, Western blot and RT-PCR. Protein levels of eNOS were evaluated by Western blot in the CECs. The production of NO was measured using the Griess reagent. RESULTS: Agmatine attenuated the expression of MMP-2 and MMP-9 induced by ischemic injury at the protein and mRNA level, while agmatine increased the expression of eNOS directly. NO production was decreased in CECs after similar insult and was increased by agmatine treatment. In the presence of a nitric oxide synthase (NOS) inhibitor, N(omega)-nitro-L-arginine methyl ester (L-NAME), the expression levels of MMP-2 were decreased, but the expression of MMP-9 was not decreased by agmatine administration. However, NO production was suppressed by a non-specific NOS inhibitor in the agmatine treatment group. CONCLUSION: Our study supports that the down-regulation of MMP-9 by agmatine runs parallel to the up-regulation of eNOS and the maintenance of functional NO release.