ISCHEMIA-REPERFUSION INJURY IN ISOLATED LUNGS

本项目的长期目标是确定 缺血和再灌注损伤离体肺， 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 肺被有毒的氧代谢产物所伤害 在局部缺血期间，当氧分压高并且葡萄糖 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 再灌注后形成。 为了验证这一假设，实验 将在分离的绵羊肺中进行，以定量影响 缺血持续时间和氧分压，证实O2- 损伤的依赖性与有毒O2的产生有关 代谢物，并确定这些代谢物的来源。 培养绵羊肺内皮细胞的平行实验 体外肺缺血-再灌注模型中的细胞将 评估内皮作为靶和损伤源。 将从犬中分离肺和肺内皮细胞， 研究证实缺血再灌注肺损伤较少 严重的在这个物种，并确定的机制， 差 支气管循环的反应和作用将 在体内和绵羊的离体肺中进行评价， 在解剖学上适合于这个目的。 血流动力学，液体 平衡，抗氧化活性和能量状态将在 孤立的肺 活力、生化功能和屏障 将在内皮细胞中测量功能。 此外，免费 自由基浓度将在两种制剂中测量， 电子顺磁共振光谱直接评估 这些物质的作用和特性。 电镜 将评估肺和单层内皮细胞 建立结构-功能相关性。 上述研究建议的治疗干预措施将 在短暂左肺缺血后急性的完整动物中进行测试 自体左肺移植术后慢性化。 初步 实验证实了这些方法的可行性和实用性。 接近。 这些结果可能对以下方面产生重大影响： 关于肺缺血-再灌注被 被认为发挥致病作用，如心肺 体外循环、肺动脉血栓内膜切除术和溶栓治疗 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.