ISCHEMIA-REPERFUSION INJURY IN ISOLATED LUNGS

这个项目的长期目标是确定机制 通过缺血和再灌注损伤离体肺和 这些机制是否与缺血再灌注有关 完整动物的肺损伤。我们假设，与其他人不同 器官--肺被产生的有毒氧代谢产物损伤 在缺血期间，当氧分压高和葡萄糖 耗尽了。内皮是损伤的主要目标， 因此，导致血管通透性增加和水肿 在再灌流时形成。为了检验这一假设，实验 将在分离的绵羊肺中进行，以量化影响 缺血持续时间和氧分压，确认O2- 损伤的依赖性与有毒O2的产生有关 代谢产物，并确定这些代谢物的来源。 绵羊肺内皮细胞培养的平行实验 肺缺血再灌流体外模型中的细胞 评估血管内皮细胞作为损伤的靶点和来源。 从狗身上分离出的肺和肺内皮细胞 研究证实缺血再灌注对肺的损伤较小 在这个物种中是严重的，并确定了 不同。支气管循环的反应和作用将 在活体和在绵羊的离体肺中进行评估 在解剖学上适合这一目的。血流动力学，液体 平衡、抗氧化剂活性和能量状态将在 肺是孤立的。生存能力、生化功能和屏障 功能将在内皮细胞中进行测量。此外，免费的 将通过以下方法测量两种制剂中的自由基浓度 电子顺磁共振波谱直接评估 这些物质的作用和识别。电子显微镜 将对肺内皮细胞和单层进行评估 执行以建立结构-功能相关性。 上述研究建议的治疗干预措施将是 在短暂性左肺缺血后在完整动物身上进行急性测试 左肺自体移植后。初步 实验结果证实了该方法的可行性和实用性。 接近了。这一结果可能会对 尊重肺缺血-再灌流的人体条件 认为起致病作用的，如心肺 搭桥术、肺血栓内膜剥脱术及术后溶栓 肺栓塞和肺移植。

The long term goal of this project is to determine the mechanisms by which ischemia and reperfusion injure the isolated lung and whether these mechanisms are relevant to ischemia-reperfusion lung injury in intact animals. We hypothesize that unlike other organs the lung is injureed by toxic oxygen metabolites generated during ischemia, when oxygen tension is high and glucose depleted. The endothelium is a primary target of injury, which, therefore, results in increased vascular permeability and edema formation upon reperfusion. To test this hypothesis, experiments will be performed in isolated sheep lungs to quantitate the effects of ischemic duration and oxygen tension, confirm that the O2- dependence of the injury is related to production of toxic O2 metabolites, and determine the source of these metabolites. Parallel experiments using cultured sheep pulmonary endothelial cells in an in vitro model of lung ischemia-reperfusion will evaluate endothelium both as a target and as a source of injury. Isolated lungs and pulmonary endothelial cells from dogs will be studied to confirm that ischemia-reperfusion lung injury is less severe in this species and to determine the mechanisms of the difference. The response and role of the bronchial circulation will be evaluated in vivo and in isolated lungs from sheep, a species anatomically suited to this purpose. Hemodynamics, fluid balance, antioxidant activity and energy state will be measured in isolated lungs. Viability, biochemical function, and barrier function will be measured in endothelial cells. In addition, free radical concentrations will be measured in both preparations by eletron paramagnetic resonance spectroscopy to assess directly the role and identify of these substances. Electron microscopic evaluation of endothelium in lung and monolayer will be performed to establish structure-function correlations. Therapeutic interventions suggested by the above studies will be tested in intact animals acutely after transient left lung ischemia and chroncially after left lung autotransplantation. Preliminary experiments confirm the feasibility and usefulness of these approaches. The results could have significant implications with respect to human conditions in which lung ischemia-reperfusion is thought to play a pathogenetic role, such as cardiopulmonary bypass, pulmonary thromboendarectomy and thrombolysis after pulmonary embolism, and lung transplantation.