Newborn brain oxygenation and cellular injury

新生儿脑氧合和细胞损伤

• 批准号: 6611375
• 负责人: Anna Pastuszko
• 金额: $ 32.1万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-17 至 2006-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6611375
• 关键词: apnea; brain circulation; brain injury; brain metabolism; corpus striatum; cytotoxicity; dopamine; gene expression; high performance liquid chromatography; hydroxyl radical; hypoxia; immunocytochemistry; microdialysis; newborn animals; nucleic acid amplification techniques; oxygen tension; phosphorescence; respiratory distress syndrome of newborn; swine; terminal nick end labeling

DESCRIPTION (provided by applicant): Repetitive apnea is commonly associated with the perinatal period. Apneic episodes longer than 15 s and accompanied by hypoxia or bradycardia have been reported to occur in all infants with gestational ages less than 34 weeks. Apneic episodes requiring ventilatory support or pharmacologic intervention occur in at feast 50% of surviving infants weighing less than 1500 g at birth. The cumulative effect of brief but repetitive apnea may have clinical significance for later neurological function. The physiological mechanisms of apneic spells, however, are still poorly understood, due in part to the lack of reliable measurements of oxygenation of the brain. In these studies, the oxygen dependent quenching of phosphorescence, a noninvasive optical method for measuring oxygen developed in our laboratory, will be used to measure the oxygen in the microvasculature of the brain tissue. This method will allow continuous evaluation of the status of tissue oxygenation during apnea and post-apneic recovery. Thus, it will be possible, for the first time, to comprehensively analyze the changes in oxygen pressure that occur in the brain during apnea and recovery. Our experimental model will be newborn piglets. The different levels of inspired oxygen used during apnea models and post-apnetic recovery will represent clinically relevant conditions. The oxygen measurements will be coupled with measurements of the status of brain metabolism and the extent of brain injury. The mechanism(s) of cellular dysfunction and/or injury induced by the apnea will be examined at both the cellular and molecular levels. Changes in extracellular levels of dopamine and hydroxyl radicals, measured by in vivo microdialysis, will be used as markers of tissue hypoxia and a cellular dysfunction. The role of dopamine and hydroxyl radicals in brain injury will be also determined. The amplified antisense RNA (aRNA) technique will be used to screen multiple genes that may be altered in expression level during apnea and recovery. The genes which were chosen are directly or indirectly associated with dopamine. The morphological, immunohistochemical, temporal patterns and the severity of damage will be determined using standard histologic staining with Fluoro-Jade, and antibodies against APP/APLP and GFAP. These studies will result in a better understanding of the mechanisms causing the brain injury in response to repetitive apnea and provide an approach to evaluating the efficacy of procedural alterations designed to minimize this injury.

描述（由申请人提供）：重复呼吸暂停通常与围产期相关。据报道，呼吸暂停发作超过15 s，伴随着缺氧或心动过缓的伴随着所有胎龄小于34周的婴儿。需要通气支持或药理干预的呼吸暂停发作发生在盛宴中，有50％的尚存婴儿的体重小于1500 g。简短但重复的呼吸暂停的累积效应对于后来的神经功能可能具有临床意义。然而，呼吸暂停咒语的生理机制仍然很少了解，部分原因是缺乏可靠的大脑氧合测量。在这些研究中，磷光的氧气依赖性淬灭，一种用于测量我们实验室中开发的氧气的非侵入性光学方法，将用于测量脑组织微脉管系统中的氧气。该方法将允许在呼吸暂停和彼尔尼克后恢复期间连续评估组织氧合的状态。因此，首次有可能全面分析呼吸暂停和恢复过程中大脑中发生的氧气变化。我们的实验模型将是新生小猪。在呼吸暂停模型和通气后恢复过程中使用的不同水平的氧气将代表临床上相关的条件。氧测量将与脑代谢状况和脑损伤程度的测量结果结合使用。呼吸暂停引起的细胞功能障碍和/或损伤的机制将在细胞和分子水平上检查。通过体内微透析测量的多巴胺和羟基自由基的细胞外水平的变化将用作组织缺氧和细胞功能障碍的标志。还将确定多巴胺和羟基自由基在脑损伤中的作用。放大的反义RNA（ARNA）技术将用于筛选多个基因，这些基因在呼吸暂停和恢复过程中可能会改变表达水平。选择的基因直接或间接与多巴胺相关。形态学，免疫组织化学，时间模式和损害的严重程度将使用标准的组织学染色，用氟jade和针对APP/APLP和GFAP的抗体进行。这些研究将更好地理解导致重复呼吸暂停的脑损伤的机制，并提供一种方法来评估旨在最大程度地减少这种损伤的程序改变的功效。