Protective effects of BQ-123, an ET(A) receptor antagonist, against leukotoxin-induced injury in rat lungs

We tested the hypothesis that BQ-123, a novel endothelin type A (ET(A)) receptor antagonist, protects the lung against leukotoxin 9,10-epoxy-12-octadecenoate (Lx), which causes acute lung injury in animals. In isolated rat lungs perfused with Earle's balanced salt solution, BQ-123 suppressed the Lx-induced increase in wet lung weight, wet lung weight/dry lung weight, the effluent perfusate lactic dehydrogenase activity, and effluent perfusate and lung tissue ET-1 levels. BQ-123 also significantly attenuated the Lx-induced increase of the pulmonary capillary filtration coefficient. Thus our experimental results indicate that the ET(A) receptor antagonist, BQ-123, protects against Lx-induced experimental lung vascular injury.