一氧化氮合酶基因表达在新生鼠缺氧性脑损伤中的作用

新生儿缺氧性脑损伤可导致永久性神经功能损害。我们测定新生鼠缺氧性脑损伤模型服组织内诱生型一氧化氮合酶（ｉｎＯＳ）ｍＲＮＡ表达变化,以阐明它在发病中的作用。取新生ＳＤ鼠随机分组制作模型并行病理鉴定;采用ＲＴ－ＰＣＲ测定脑缺氧时脑组织细胞内ｉＮＯＳｍＲＡＮ表达的变化,深度度扫描获取数值。实验显示,缺氧２小时后损伤脑组织的ｉＮＯＳｍＲＮＡ表达显著升高（Ｐ〈０．００１）。结果表明,新生鼠缺氧后神经系统诱生     

一氧化氮及诱导型一氧化氮合酶与早产儿脑室周围白质软化

脑室周围白质软化是早产儿脑白质损伤中最主要的类型之一,脑缺氧缺血和宫内感染被认为是其发病的两大因素。脑缺氧缺血和宫内感染均可使患儿体内的细胞因子水平增高并激活,启动脑组织中诱导型一氧化氮合酶的大量表达,从而产生过量的一氧化氮发挥神经毒性作用,其中心环节在于一氧化氮对少突胶质细胞前体细胞的损伤作用。     

新生大鼠脑白质损伤时神经胶质细胞凋亡与iNOS的表达

目的：诱导型一氧化氮合酶(iNOS) 是缺氧缺血（HI）后引起一氧化氮过量产生的主要限速酶,该研究通过观察HI后神经胶质细胞凋亡及iNOS表达的变化,探讨新生大鼠脑白质损伤(WMD)的发病机制。方法：将112只2日龄未成熟大鼠随机分为WMD组和假手术 (对照) 组,建立新生大鼠WMD模型,分别于HI后1 h、3 h、6 h、12 h、1 d、3 d及7 d处死,采用免疫组织化学法检测脑组织iNOS的表达,TUNEL法测定胶质细胞凋亡。结果：与对照组比较,WMD组iNOS于HI后1 h表达开始上升,1 d达到高峰;神经胶质细胞凋亡于HI后1 h显著增多,在HI后1 d达到高峰。结论：WMD新生大鼠中iNOS的表达显著增高可能导致神经胶质细胞的凋亡,参与HI后WMD的病理生理过程。     

脉络宁抗新生鼠缺氧缺血性脑损伤作用及其机制探讨

目的 研究新生SD鼠缺氧缺血后大脑皮质谷氨酸和天冬氨酸的变化，观察脑神经元型一氧化氮合酶（nNOS）和c-fos蛋白的表达，探讨脉络宁对缺氧缺血性脑损伤（HIBO）的保护作用。方法 结扎新生7日龄SD大鼠右侧颈总动脉1h（缺血1h），吸入8％氧和92％氮2h（缺氧2h），建立HIBD模型。用色谱分析仪测定大脑皮质内谷氨酸和天冬氨酸含量，用免疫组化方法动态评价缺氧缺血和脉络宁治疗不同时相c-fos蛋白和nNOS的表达。结果 缺氧缺血后大脑皮质兴奋性氨基酸（ZAA）水平升高，经脉络宁处理后则明显降低。c-fos蛋白表达的高峰期呈现在缺氧缺血6h后，与缺氧缺血组相比，脉络宁处理后c-fos蛋白表达的脑神经元数目增多；与假手术组相比，缺氧缺血可上调nNOS的表达水平，脉络宁处理后则减少了nNOS的表达。结论 脉络宁通过改善神经元功能减少EAA的释放，调节nNOS的免疫活性，对神经元起保护作用。脉络宁可增强和延长神经元内c-fos蛋白的表达，减轻HIBD，推测c-fos参与了缺氧缺血后大脑皮质和海马神经元损伤后的修复、存活与再生。     

缺血再灌注大鼠肾脏诱导型一氧化氮合酶表达的意义

目的观察缺血及缺血再灌注(IR)大鼠肾脏诱导型一氧化氮合酶(iNOS)表达变化的规律。方法制作大鼠肾脏缺血及IR模型,不同时间摘取肾脏,免疫组织化学法检测iNOS表达变化。HE染色观察肾脏损伤程度。结果缺血时及IR后iNOS表达均明显增强(P<0.05),且随时间呈一定的变化规律,呈先升高后下降趋势,24 h达峰值,72 h时降至2 h水平。结论肾脏缺血早期iNOS即起损伤作用,并于再灌注后加重损伤。     

XIAP过度表达对新生小鼠缺氧缺血后脑组织硝基酪氨酸和4-羟基壬烯醛表达的影响

目的探讨X-染色体连锁的凋亡抑制剂(XIAP)过度表达对正常凋亡相关蛋白的影响,以及XIAP对未成熟脑在缺氧缺血(HI)后硝基酪氨酸和4-羟基壬烯醛(4-HNE)形成的影响。方法新生9日龄转基因XIAP过度表达及同期野生型C57BL/6小鼠在HI(结扎左颈总动脉加10%氧气吸入55min)后3、24、72h处死,取脑组织进行硝基酪氨酸和4-HNE免疫组化染色;部分未进行HI的动物取脑组织进行匀浆用于Western蛋白印迹。结果West鄄ern蛋白印迹显示雌性转基因动物XIAP蛋白表达量高于雄性,XIAP过度表达组和野生组脑组织中细胞色素C、凋亡诱导因子、半胱天冬酶-9、半胱天冬酶-3、诱导型一氧化氮合酶、神经元型一氧化氮合酶含量差异均无显著性。免疫组化显示HI后24hXIAP过度表达组大脑皮层和海马CA1区硝基酪氨酸和4-HNE阳性细胞数明显低于野生组(P均<0.01)。结论XIAP过度表达对正常情况下凋亡相关蛋白表达无影响,其对缺氧缺血性脑损伤的保护作用可能与减轻氧化应激损伤有关。     

新生大鼠缺氧缺血性脑损伤iNOS mRNA表达变化

目的　 研究新生大鼠缺氧缺血性脑损伤 (HIBD)时诱导型一氧化氮合酶 (iNOS)mRNA的表达变化。 方法 　制备新生大鼠左脑HIBD的模型。用反转录聚合酶链反应 (RT PCR)检测HIBD后 6h、2 4h、48h、5d不同时点脑皮层iNOSmRNA的表达情况。经凝胶成像及分析系统扫描RT PCR产物 ,用内参半定量分析iNOSmRNA的动态变化。同时观察光镜下神经元坏死变化。 结果 　 7日龄Wistar大鼠对照组没有iNOSmRNA表达 ,HIBD 6h开始表达 ,HIBD 2 4～ 48h为表达高峰 (与HIBD 6h相比有显著性差异 ,P <0 0 1) ,此后逐渐下降 ,HIBD 5d仍可检测出 (与HIBD 6h相比有显著性差异 ,P <0 0 1)。观察光镜下神经元坏死在HIBD后 2 4～ 48h最显著。 结论 　新生大鼠HIBD可诱导iNOS基因表达 ,其可能参与HIBD后的神经毒性损伤     

药物干预幼大鼠缺氧缺血性脑损伤与p53蛋白表达的研究

目的通过检测缺氧缺血性脑损伤(HIBD)幼大鼠脑组织中p53蛋白的表达和一氧化氮(NO)、一氧化氮合酶(NOS)、超氧化物歧化酶(SOD)含量,探讨HIBD的发病机制;了解神经节苷酯(GM1)和胞二磷胆碱干预对HIBD的影响。方法80只Wistar幼大鼠随机分四组;对照组、缺氧缺血组、GM1组、胞二磷胆碱组。17日龄制作HIBD模型,24 h后处死检测脑组织中p53蛋白的表达和NO、NOS、SOD含量及组织形态学的变化。结果缺氧缺血组NO、NOS含量高于其他三组(P<0.05);缺氧缺血组与胞二磷胆碱组SOD含量低于对照组和GM1组(P<0.05);缺氧缺血组p53蛋白表达高于其他三组(P<0.01),GM1和胞二磷胆碱组p53蛋白表达高于对照组(P<0.01);组织形态学改变显示,缺氧缺血组变性、坏死严重,GM1组与胞二磷胆碱组次之,对照组正常。结论NO和自由基引起的组织损伤可能诱导p53蛋白表达导致HIBD。GM1和胞二磷胆碱能改善脑组织NO、NOS、SOD含量和p53的表达,提示GM1和胞二磷胆碱对HIBD有一定的保护作用。     

一氧化氮、一氧化氮合酶与脑缺氧缺血

许多实验证明一氧化氮 (ＮＯ)与脑缺氧缺血 (ＨＩ)的病理生理反应有关。现将ＮＯ在缺血现象中的神经毒性和神经保护作用、ＮＯ和兴奋性氨基酸 (ＥＡＡ)、胰岛素样生长因子(ＩＧＦ 1)的关系综述如下。一、ＮＯ在脑中的生物合成　ＮＯ是中枢神经系统的生理信使[1] ,由一氧化氮合酶 (ＮＯＳ)作用于Ｌ Ａｒｇ、分子氧产生 ,参与转导途径 ,在生理状态下致细胞内ｃＧＭＰ升高。ＮＯ可能调节脑血流 (ＣＢＦ)和记忆。脑ＮＯＳ至少有三型[1] :神经元表达神经元型ＮＯＳ(ｎＮＯＳ) ,神经胶质 (星形细胞 ,小神经胶质和少突神经胶质 )表达诱导型ＮＯＳ(…     

一氧化氮合酶在脑缺氧缺血中的双重作用

一氧化氮合酶（ＮＯＳ）在脑缺氧缺血（ＨＩ）中的双重作用已日益受到重视，本文分别阐述了三种不同亚型的ＮＯＳ在脑ＨＩ中的神经保护作用和神经毒性作用，并展望了ＮＯＳ抑制剂在ＨＩ脑损伤中的应用前景。     

促红细胞生成素对缺氧缺血新生鼠脑匀浆一氧化氮及血浆内皮素的影响

目的探讨体外注射重组人促红细胞生成素(rhEPO)对新生鼠缺氧缺血后脑组织一氧化氮(NO)和NO合成酶(NOS)及血浆内皮素(ET)水平的影响,阐明其对缺氧缺血(HI)新生动物神经保护作用的机制。方法将7日龄SD大鼠制备缺氧缺血脑损伤(HIBD)模型及rhEPO治疗模型,将假手术组作对照。测定各组新生鼠HI后6 h脑组织匀浆NO和NOS含量以及血浆ET水平。结果HIBD组在HI后6 h脑组织NO、NOS及血浆ET均升高(P<0.05),rhEPO组脑组织NO、NOS显著降低水平(P<0.05),而血浆ET含量无明显改变。结论外源性rhEPO可通过减少NO的过量生成而对HIBD后的脑组织起到保护作用。     

Protective effect of aminoguanidine on hypoxic-ischemic brain damage and temporal profile of brain nitric oxide in neonatal rat

Nitric oxide (NO) produced by inducible NO synthase contributes to ischemic brain damage. However, the role of inducible NO synthase-derived NO on neonatal hypoxic-ischemic encephalopathy has not been clarified. We demonstrate here that aminoguanidine, a relatively selective inhibitor of inducible NO synthase, ameliorated neonatal hypoxic-ischemic brain damage and that temporal profiles of NO correlated with the neuroprotective effect of aminoguanidine. Seven-day-old Wister rat pups were subjected to left carotid artery occlusion followed by 2.5 h of hypoxic exposure (8% oxygen). Infarct volumes (cortical and striatal) were assessed 72 h after the onset of hypoxia-ischemia by planimetric analysis of coronal brain slices stained with hematoxylin-eosin. Aminoguanidine (300 mg/kg i.p.), administered once before the onset of hypoxia-ischemia and then three times daily, significantly ameliorated infarct volume (89% reduction in the cerebral cortex and 90% in the striatum; p<0.001). NO metabolites were measured by means of chemiluminescence using an NO analyzer. In controls, there was a significant biphasic increase in NO metabolites in the ligated side at 1 h (during hypoxia) and at 72 h after the onset of hypoxia (p<0.05). Aminoguanidine did not suppress the first peak but significantly reduced the second one (p<0.05), and markedly reduced infarct size in a neonatal ischemic rat model. Suppression of NO production after reperfusion is a likely mechanism of this neuroprotection.     

促肾上腺皮质激素释放因子与缺氧缺血性脑损伤

促肾上腺皮质激素释放因子(CRF)是一种与应激密切相关的神经内分泌肽,研究证明,应激可导致人和动物血液CRF水平升高,且高水平的CRF促使下丘脑神经元钙离子内流.新生儿出生时发生缺氧缺血性应激,血液CRF水平能否作为脑损伤严重程度的一个评价指标越来越受到新生儿科医生的关注.本文就近年来有关CRF及其受体、CRF分泌、生理作用及调节、缺氧缺血应激与CRF的关系作一综述,为新生儿缺氧缺血性脑损伤严重程度的评价提供理论依据.     

Pharmacotherapeutical reduction of post-hypoxic-ischemic brain injury in the newborn

Perinatal hypoxia-ischemia (PHI) is a major cause of morbidity and mortality. A substantial part of PHI-related brain damage occurs upon reperfusion and reoxygenation by the excess production of excitatory amino acids, free (pro)radicals and the release of cytokines, triggering programmed cell death. In this respect, several neuroprotective agents have been investigated in neonatal animal models, providing evidence for their usefulness in PHI. Several agents have been shown to be neuroprotective in neonatal animal hypoxia-ischemia models, but only a few agents have been used in clinical studies on term newborns. Although some general information will be provided with respect to focal hypoxia-ischemia and neuroprotective agents, this paper focuses on the investigated neuroprotective agents for global PHI and reperfusion brain injury in the newborn, categorized by their mode of action. Future experimental and clinical trials with promising neuroprotective agents need to be performed, including long-term follow-up to monitor long-term consequences. Moreover, well-designed combinations of neuroprotective agents with or without other neuroprotective strategies such as brain hypothermia should be given consideration for producing the most promising results in reducing post-hypoxic-ischemic reperfusion injury of the newborn brain.     

Neuroprotective effect of nipradilol, an NO donor, on hypoxic-ischemic brain injury of neonatal rats

Hypoxia-ischemia is a common cause of neonatal brain injuries. Nitric oxide (NO) is upregulated in the brain after hypoxia-ischemia and generally believed to exert a paradoxical effect on neurons, neurodestruction and neuroprotection, but it has not been demonstrated that NO is actually neuroprotective in neonatal hypoxic-ischemic encephalopathy. We evaluated the effect of intracerebroventricular administration of nipradilol (3,4-dihydro-8-(2-hydroxy-3-isopropylamino)-propoxy-3-nitroxy-2H-1-benzopyran), a potent NO donor, at various concentrations (0.1 muM to 1 mM in 5 mul PBS/brain) to neonatal rats with hypoxic-ischemic treatment. The extent of the infarct area in the brain was significantly reduced by injection of the 1 muM nipradilol solution. However, denitro-nipradilol (3,4-dihydro-8-(2-hydroxy-3-isopropylamino)-propoxy-3-hydroxy-2H-1-benzopyran), that does not release NO, did not show the neuroprotective effect, suggesting that NO released from nipradilol exerts a neuroprotective effect on neonatal neurons.     

内毒素血症对新生鼠脑一氧化氮合酶表达的影响

目的　在脑的正常发育及一些病理条件下 ,一氧化氮合酶 (NOS)发挥一定作用 ,但不同亚型的NOS作用不同。该研究观察正常新生鼠脑以及内毒素血症时新生鼠脑 3种一氧化氮合酶 (NOS)亚型蛋白的表达 ,并探讨脂多糖 (LPS)和地塞米松 (DXM)对其表达的影响。方法　生后健康 7日龄Wistar大鼠 6 8只 ,随机分为对照组、内毒素血症组 (腹腔内注射E .coliLPS 5mg kg)及DXM组 (LPS 5mg kg +DXM 10mg kg) ,分别于用药后2 ,4 ,6 ,2 4h取脑进行NOS免疫组织化学染色。结果　正常对照组新生大鼠脑神经元型NOS(nNOS)明显表达 ,内皮型NOS(eNOS)微弱表达 ,诱导型NOS(iNOS)无表达。LPS腹腔注射后 4hnNOS表达开始增加 ;eNOS及iNOS表达于 6h开始增加 ,3者表达均于 2 4h时达高峰 ;3种NOS表达阳性细胞主要分布于脑皮质、海马、下丘脑、脑室旁核团、纹状体神经细胞。除此之外 ,nNOS在梨状皮质有较强表达 ,eNOS及iNOS在血管内皮细胞呈微弱表达。3种NOS亚型蛋白表达在DXM注射后 2～ 6h受到明显抑制 ,并持续至用药后 2 4h。结论　正常新生鼠脑表达nNOS及eNOS ,无iNOS表达 ;LPS诱导 3种NOS亚型的表达 ,其表达的部位及受诱导表达的程度亦不同 ,提示NOS在中枢神经系统的正常发育及LPS诱导的内毒素血症脑损伤发病中发挥一定作用 ,DXM具有神     

早产儿脑损伤生物标志物的研究进展

随着围产及新生儿监护技术的不断发展,早产儿的生存率不断提高,与此同时早产儿脑损伤的发生率也在逐渐上升,常遗留不同程度的认知障碍与运动障碍。脑损伤生物标志物检测是诊断脑损伤的重要手段,根据损伤细胞的性质不同可分为神经胶质细胞损伤标志物、神经元损伤标志物及其他生物标志物等几大类,而其中较为成熟并广泛应用于临床的有S100B蛋白、髓鞘碱性蛋白、神经元特异性烯醇化酶等生物标志物。最新研究发现胶质纤维酸性蛋白、神经丝轻链蛋白、α-Ⅱ血影蛋白裂解产物、趋化因子、褪黑素及尿液代谢组学等指标可提示早产儿潜在脑损伤,检测这些生物标志物有助于早产儿脑损伤的早期诊断及早期治疗,对改善其神经发育预后至关重要。该文就早产儿脑损伤生物标志物的最新研究进展作一综述,以期为早产儿脑损伤的早期诊断及早期治疗提供有效依据。     

Hypoxic-ischemic brain damage in perinatal age group

Cerebral hypoxia-ischemia in the perinatal period continues to be a major contributor to chronic neurologic impairment in children worldwide. Extensive research conducted in the past several years has led to a better understanding of the mechanisms involved in hypoxic-ischemic brain injury. Based on this understanding, the major potential therapeutic approaches being studied include antagonists of excitatory amino acids, calcium channel antagonists, free-radical scavengers, nitric oxide synthase inhibitors, anti-inflammatory agents, trophic factors, and hypothermia. Several agents are in clinical trial phases in adults. However, safety concerns and close relationship between pathomechanisms of hypoxic-ischemic cerebral injury and normal developmental processes have contributed to the slow pace in the neonatal trials. Large multicenter trials including an adequate number of infants will be needed to evaluate efficacy of therapeutic interventions in this particular age group. A large number of risk factors that predispose to hypoxic ischemic injury have been identified, It is important to control these factors and prevent brain damage in the first place. This is especially true for developing countries where resources for treatment with newer agents (when they become available) are likely to be limited. Recent information regarding mechanisms of injury and potential therapeutic measures related to perinatal age are presented in this paper.     

人脐带间充质干细胞移植对新生大鼠缺氧缺血性脑损伤的保护作用

目的 探讨人脐带间充质干细胞（hUC-MSCs）对新生大鼠缺氧缺血性脑损伤（HIBD）的保护作用及可能机制。方法 10 日龄 Sprague-Dawley 大鼠随机分为假手术组、HIBD 组和 MSCs 组,建立新生大鼠HIBD 模型,建模后 24 h MSCs 组侧脑室注入 hUC-MSCs。移植后 24、48 h 应用 TUNEL 及 Western blot 分别检测细胞凋亡及 Caspase-3 的表达;移植后 1、2、3 周应用 Longa 评分评价大鼠的神经行为,免疫荧光观察 hUC-MSCs 的存活、分化情况。结果 移植后 24、48 h,MSCs 组大鼠的细胞凋亡及 Caspase-3 的表达较 HIBD 组减少（PPPP结论 hUC-MSCs 移植治疗新生大鼠 HIBD 时,早期可抑制 Caspase-3的表达,减少细胞凋亡;后期存活的 hUC-MSCs 可分化为神经样细胞,并促进内源性神经样细胞的分化,发挥脑保护作用。     

The influence of growth retardation on perinatal hypoxic-ischemic brain damage

The effect of growth retardation on the extent of brain damage produced by hypoxia-ischemia was assessed in immature rats. Newborn rats were raised in litters of 6 or 14 pups from day 2 to 7. On postnatal day 7, those immature rats raised in litters of 14 weighed 18% less than animals raised in litters of 6 (P less than 0.001). They then were subjected to cerebral hypoxia-ischemia by unilateral common carotid artery ligation followed by 3 h of exposure to 8% oxygen-92% nitrogen at 37 degrees C. Upon return to their dams, all litters were culled to 6 pups. At 30 days of age, the animals underwent perfusion-fixation of their brains under pentobarbital anesthesia. Brain damage was assessed by measuring the length and width of each cerebral hemisphere. The extent of brain damage varied from no difference in the size of the two cerebral hemispheres to marked shrinkage of the hemisphere ipsilateral to the common carotid artery occlusion. The range of brain damage between the well-nourished and poorly nourished animals was comparable. Rank order of the extent of damage demonstrated significantly greater tissue injury in those animals well nourished prior to hypoxia-ischemia (Mann-Whitney U-test; P = 0.003). The results indicate that nutritional deprivation in the immature rat is associated with a decreased rather than increased susceptibility to brain damage arising from hypoxia-ischemia. The findings of the investigation have relevance to the human infant suffering from intrauterine growth retardation (IUGR).