Newborn brain oxygenation and cellular injury

新生儿脑氧合和细胞损伤

• 批准号: 6513861
• 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/6513861
• 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）：重复性呼吸暂停通常与围产期有关。据报道，所有胎龄小于 34 周的婴儿都会出现呼吸暂停发作时间超过 15 秒并伴有缺氧或心动过缓的情况。出生时体重低于 1500 克的存活婴儿中，至少 50% 会发生需要通气支持或药物干预的呼吸暂停发作。短暂但重复性呼吸暂停的累积效应可能对以后的神经功能具有临床意义。然而，呼吸暂停的生理机制仍然知之甚少，部分原因是缺乏对大脑氧合的可靠测量。在这些研究中，磷光的氧依赖性猝灭是我们实验室开发的一种用于测量氧气的无创光学方法，将用于测量脑组织微脉管系统中的氧气。该方法将允许连续评估呼吸暂停期间和呼吸暂停后恢复期间的组织氧合状态。因此，将首次能够全面分析呼吸暂停和恢复期间大脑中发生的氧压变化。我们的实验模型将是新生仔猪。呼吸暂停模型和呼吸暂停后恢复期间使用的不同吸入氧水平将代表临床相关条件。氧气测量将与脑代谢状态和脑损伤程度的测量相结合。将在细胞和分子水平上检查呼吸暂停引起的细胞功能障碍和/或损伤的机制。通过体内微透析测量的细胞外多巴胺和羟自由基水平的变化将被用作组织缺氧和细胞功能障碍的标志。多巴胺和羟基自由基在脑损伤中的作用也将被确定。扩增的反义RNA（aRNA）技术将用于筛选在呼吸暂停和恢复期间表达水平可能发生改变的多个基因。所选择的基因与多巴胺直接或间接相关。将使用 Fluoro-Jade 的标准组织学染色以及针对 APP/APLP 和 GFAP 的抗体来确定形态学、免疫组织化学、时间模式和损伤的严重程度。这些研究将有助于更好地理解重复性呼吸暂停导致脑损伤的机制，并提供一种方法来评估旨在最大限度地减少这种损伤的程序改变的效果。