Contribution of Endothelin-1 to Warm Ischemia/Reperfusion Injury of the Rat Lung

The purpose of the present study was to clarify the role of endothelin-1 (ET-1) in the pathogenesis of ischemia/reperfusion lung injury and to determine whether pretreatment with an ET receptor antagonist prevents such injury. The left lung of Sprague-Dawley rats was subjected to 60 min of no-flow warm ischemia followed by 90 min of reperfusion. The plasma ET-1 concentration increased significantly after reperfusion compared with before and after ischemia (p < 0.05). Arterial oxygen tension was reduced, and the lung tissue wet/dry weight ratio increased in post-reperfusion lungs compared with both pre-ischemia and post-ischemia lungs. Histologic study showed pulmonary edema, hemorrhage, hyaline membrane formation, and a significant increase in lung tissue neutrophils after reperfusion. In addition, the expression of ET-1 mRNA was determined by Northern blot analysis. Although ischemia did not significantly alter ET-1 expression, reperfusion increased expression in the left lung markedly and in the right lung moderately. Pre-infusion of FR139317, an ETA receptor antagonist, prevented post-reperfusion damage to the lung. These results suggest that ET-1 contributes to the ischemia/reperfusion injury of the rat lung, mediated by an ETA receptor, and that an ETA receptor antagonist may inhibit ischemia/reperfusion lung injury.