STRESS PRECONDITIONING AND ALVEOLAR EPITHELIAL INJURY

描述：(逐字摘自申请者摘要)创伤和出血 休克是人类急性肺损伤的主要原因之一。20%至 25%的严重创伤患者会出现急性肺损伤， 创伤是继败血症之后导致急性肺损伤的第二大常见原因。 内源性促进肺泡上皮液转运的研究 儿茶酚胺是防止术后肺泡泛滥的主要机制 失血性休克。然而，在严重出血后，这种保护机制 通过发展对肺泡的氧化应激而被消除 上皮组织。这种肺屏障的氧化应激是由释放的 大量的一氧化氮(NO)和自由基氧物种 直接改变膜蛋白的功能，参与 肺泡上皮和肺组织中β-肾上腺素能受体-cAMP信号通路 通过将中性粒细胞隔离在肺中放大氧化应激 在肺泡上皮中。 热休克或应激反应是一种高度保守的细胞防御。 以应激蛋白表达增加为特征的机制 允许细胞承受随后的致命侮辱，这是一种现象 称为“耐热性”或“预适应”。应激预适应 热已被证明可以保护肺免受缺血再灌注损伤， 尽管人们对保护机制知之甚少。我们的预赛 数据表明，无论是用热还是用水诱导耐热性 非热刺激恢复肺泡上皮液正常转运 大鼠严重出血。因此，我们建议检验这一假设 丹参对肺泡上皮细胞氧化应激的保护作用 热应激预适应是通过：(A)减少 抑制血管紧张素转换酶基因表达引起的肺炎性反应 直接抑制离子的促炎介质(NO、过氧亚硝酸盐) 跨肺泡上皮运输(目标1)；(B0) 减少严重出血后中性粒细胞在肺内的滞留 中性粒细胞从骨髓中释放，并通过增加 中性粒细胞凋亡，以及通过减少黏附的表达 肺内皮细胞表面分子和空隙释放 趋化因子CINC-1和/或MIP-2。(目标2)。在本提案的目标3中，我们将 探索应激预适应(使用临床相关策略，如 作为格尔达霉素或热休克蛋白32表达的直接诱导剂)，防止 失血后肺泡上皮细胞的氧化应激反应。

DESCRIPTION: (Verbatim from the applicant's abstract) Trauma and hemorrhagic shock are one of the major causes of acute lung injury in humans. Twenty to twenty-five percent of patients with severe trauma develop acute lung injury, and trauma is the second most common cause of acute lung injury after sepsis. Upregulation of alveolar epithelial fluid transport by endogenous catecholamines is a major mechanism that prevents alveolar flooding after hemorrhagic shock. However, after severe hemorrhage, this protective mechanism is abolished by the development of an oxidative stress to the alveolar epithelium. The oxidative stress to this lung barrier is caused by the release of a large quamtity of nitric oxide (NO) and radical oxygen species that directly alter the function of membrane proteins involved in the beta-adrenergic receptor-cAMP signaling pathway in the alveolar epithelium and by the sequestration of neutrophils in the lung that amplify oxidative stress in the alveolar epithelium. The heat shock or stress response is a highly conserved cellular defense mechanism characterized by the increased expression of stress proteins that "allows the cells to withstand a subsequent lethal insult, a phenomenon referred as "thermotolerance" or "preconditioning." Stress preconditioning with heat has been shown to protect against ischemia-reperfusion injury to the lung, although the mechanisms of protection are poorly understood. Our preliminary data indicated that induction of thermotolerance either with heat or non-thermal stimulus restored normal alveolar epithelial fluid transport after severe hemorrhage in rats. Therefore, we propose to test the hypothesis that the protection against oxidative stress to the alveolar epithelium provided by stress preconditioning with heat is mediated by: (a) a decrease of the inflammatory response in the lung by inhibition of expression of proinflammatory mediators (NO, peroxynitrite) that directly inhibit ion transport across the alveolar epithelium (aim 1); (b0 a decrease in the neutrophil sequestration in lung after severe hemorrhage by decreasing the release of neutrophils from the bone marrow and by increasing the rate of neutrophil apoptosis, as well as by decreasing the expression of adhesion molecules on the surface of the lung endothelium and the airspace release of chemokines CINC-1 and/or MIP-2. (aim 2). In aim 3 of this proposal we will explore how stress preconditioning ( using clinically relavant strategies, such as geldanamycin or direct inducers of Hsp 32 expression), protects against oxidative stress to the alveolar epithelium after hemorrhage.