Effect of prostaglandin I2 and superoxide dismutase on reperfusion injury of warm ischemic lung.

Abstract A prostaglandin I 2 (PGI 2 ) analogue and superoxide dismutase (SOD) were administered to dogs with pulmonary denervation, and their effects on warm ischemic damage to the lung were studied. Twenty-seven adult mongrel dogs were divided into a control group (6 dogs), a PGI 2 group (7 dogs), an SOD group (6 dogs), and a heparin group (8 dogs). The left pulmonary hilum was dissected, with PGI 2 (1 μg/kg) being administered to the PGI 2 group and heparin (100 U/kg) to the heparin group. Then the left lung was placed in a warm ischemic state for 1 hour. The SOD group also received 20 mg/kg of SOD intravenously 1 minute before reperfusion. Before warm ischemia, immediately after reperfusion, and 1 hour and 2 hours afterward, the blood gases, left pulmonary vascular resistance, and other data were measured under right pulmonary artery clamping. Arterial oxygen tension showed significantly better values in the SOD and PGI 2 groups than in the control and heparin groups. The left pulmonary vascular resistance increased with time in the control group but did not increase in the PGI 2 group. Pulmonary microangiography showed that dilatation of the pulmonary arterioles was prominent in the PGI 2 group. The quantity of pulmonary extravascular fluid was significantly less in the PGI 2 and SOD groups than in the control and heparin groups. Histological examination showed marked collapse of capillaries, intraalveolar hemorrhage, and edema in the control and heparin groups, whereas these changes were only slight in the PGI 2 and SOD groups. Thus, both PGI 2 and SOD appeared to have a protective effect on the pulmonary microcirculation and tissue, and may be effective in preventing warm ischemic damage in lung transplantation.