Protective effects of BQ-123, an ETA receptor antagonist, against leukotoxin-induced injury in rat lungs.

We tested the hypothesis that BQ-123, a novel endothelin type A (ETA) 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 ETA receptor antagonist, BQ-123, protects against Lx-induced experimental lung vascular injury.