Redox Modulation of Nitric Oxide in Olfactory Dysfunction after Fetal Hypoxia

描述（由申请人提供）：研究中枢神经系统氧化应激和其他机制的最大问题之一是缺乏反映完整动物动态和生活状态的功能模型。这个问题在围产期研究中被放大了，因为胎儿是相对难以接近的。这一提议引入了一种创新的动物模型系统，该系统将嗅觉系统作为通往大脑其他部分的窗口。这说明需要做更多的研究来调查缺氧对围产期嗅觉的影响。在脑瘫（CP）患者中，感觉障碍没有像运动障碍那样受到重视，这为研究胎儿缺氧缺血（H-I）后发育障碍患者的感觉障碍问题提供了一个模型。我们的假设是活性氧（ROS）与一氧化氮的相互作用介导胎儿H-I引起的神经元损伤。我们将使用基于胎儿H-I中锰离子摄取的功能性磁共振成像（MRI）来确定完整动物的活嗅神经元功能。一氧化氮（NO）在嗅觉中起着核心作用，被认为是通过氧化还原调节活性氮物种（RNS）的形成来实现的。这些概念将采用多学科方法在最近开发的动物模型中进行测试，该模型表现出早产子宫缺血后的CP表型，模拟急性胎盘功能不全的临床病理生理学。我们之前的研究表明，在该模型中，H-I后胎儿大脑中产生ROS和RNS，母亲服用抗氧化剂可改善胎儿脑损伤。第一个目的是表征不同胎龄胎儿嗅道对H-I的发育脆弱性。通过流式细胞术和免疫组织化学证据显示，使用锰摄取的功能性MRI将与嗅上皮和嗅球的细胞损伤、死亡和凋亡相关。第二个目的是确定ROS和RNS是否介导胎儿H-I引起的嗅觉系统损伤。我们将通过测量超氧化物和脂质过氧化和/或酪氨酸s -亚硝基化和硝化的RNS来测试发育易损是否由ROS引起。我们将通过降低ROS和控制NO水平来改善缺氧缺血性损伤来验证我们的假设。在出生后的两个年龄阶段，通过对成熟嗅神经元和嗅球进行连续功能MRI和单独免疫染色来评估嗅觉系统的功能恢复情况。我们的目标是了解氧化应激和氧化还原信号在H-I神经元损伤中的关键机制，并最终为r -01应用进行研究。该模型系统将在研究迄今为止无法接触的胎儿的疾病、可塑性和恢复的其他机制以及各种病理（如肥胖）中嗅觉的产前编程方面具有价值。本研究提出了一种创新的动物模型系统，利用嗅觉系统作为大脑其他部分的窗口，解决了围产期嗅觉等感觉缺陷研究的需要，并探讨了氧化应激在嗅觉损伤中的关键机制。该模型系统将在研究迄今为止无法接触的胎儿的疾病、可塑性和恢复的其他机制以及各种病理的产前嗅觉编程方面具有价值。

DESCRIPTION (provided by applicant): One of the biggest problems of investigating oxidative stress and other mechanisms in the central nervous system is the lack of functional models that reflect the dynamic and living status of the intact animal. This problem is magnified for perinatal studies because the fetus is relatively inaccessible. This proposal introduces an innovative animal model system that uses the olfactory system as a window to the rest of the brain. It addresses the need of doing more studies investigating the effect of hypoxia on olfaction in the perinatal period. In patients with cerebral palsy (CP), sensory disabilities have not received as much attention as motor deficits and this provides a model for studying the issue of sensory disabilities among the postnatal developmental disabilities following fetal hypoxia-ischemia (H-I). Our hypothesis is that the interaction of reactive oxygen species (ROS) with nitric oxide mediates neuronal injury caused by fetal H-I. We will determine live olfactory neuron function in the intact animal using functional magnetic resonance imaging MRI that is based on the uptake of manganese ion in fetal H-I. Nitric oxide (NO) plays a central role in olfaction and is thought to do so by redox regulation with the formation of reactive nitrogen species (RNS). These concepts will be tested using a multidisciplinary approach in a recently developed animal model manifesting a CP phenotype following preterm uterine ischemia mimicking the clinical pathophysiology of acute placental insufficiency. We have previously shown that ROS and RNS are produced in fetal brain after H-I in this model, and administration of antioxidants to the mother ameliorates fetal brain injury. The first aim characterizes the developmental vulnerability of the olfactory tract to fetal H-I at various gestational ages. Functional MRI using manganese uptake will be correlated with cell injury, death and apoptosis by flow cytometry and immunohistochemical evidence in the olfactory epithelium and olfactory bulbs. The second aim determines if ROS and RNS mediate injury to the olfactory system caused by fetal H-I. We will test whether the developmental vulnerability is due to ROS by measuring superoxide and lipid peroxidation and/or RNS by S-nitrosylation and nitration of tyrosine. We will test our hypothesis by amelioration of the hypoxic-ischemic injury by decreasing ROS and manipulating levels of NO. The functional recovery of olfactory system will be assessed by serial functional MRI and separate immunostaining of mature olfactory neurons and olfactory bulbs at two postnatal ages. Our objectives are to understand key mechanisms of oxidative stress and redox signaling in neuronal injury from H-I and to ultimately generate the studies for an R-01application. This model system will be valuable in the study of other mechanisms of disease, plasticity, and recovery in the hitherto inaccessible fetus, and prenatal programming of smell in diverse pathologies, such as in obesity. The proposal introduces an innovative animal model system that uses the olfactory system as a window to the rest of the brain, addresses the need of doing more studies investigating sensory deficits such as olfaction in the perinatal period, and investigates a key mechanism of oxidative stress in olfactory injury. This model system will be valuable in the study of other mechanisms of disease, plasticity, and recovery in the hitherto inaccessible fetus and prenatal programming of smell in diverse pathologies.