Preventive influence of inhaled nitric oxide on lung ischemia-reperfusion injury

In lung transplantation, lung ischemia-reperfusion injury is a serious problem when using long-term preserved grafts. A warm ischemic lung model was prepared using rabbits. NO was administered by inhalation (group I, n = 9). The control group was not administered NO (group II, n = 8). Severe ischemia-reperfusion injury occurred as evidenced by hypoxia and lung edema. PaO2 at 120 min after reperfusion was 325 +/- 41 mmHg in group I and 40 +/- 6 mmHg in group II. The pulmonary blood flow of the left lung at 120 min after reperfusion was 51% +/- 3% in group I and 20% +/- 5% in group II. The wet-to-dry weight ratio was 5.5 +/- 0.2 for the right lungs, 5.8 +/- 0.8 for the left lung in group I, and 6.1 +/- 0.4 for the left lung in group II. Histopathologically, marked hemorrhage, hyaline membrane formation, and leukocyte infiltration were observed in group II but not in group I. These data suggested that inhaled NO reduced warm ischemia-reperfusion injury in the lung, and also contributed to a better preserved lung function.