Effects of Monastral blue on pulmonary arterial blood pressure and lung and liver particle retention in chickens

Abstract

The effects of intravenous administration of the vascular tracer Monastral blue (MB) on pulmonary arterial blood pressure and the retention of MB by lung and liver were assessed in anesthetized White Leghorn cocks. Pulmonary arterial blood pressure and systemic blood pressure were measured by direct cannulation. Administration of MB alone had no effect on either pulmonary arterial blood pressure or systemic arterial blood pressure; however, following pretreatment with endotoxin (ENDO), infusion of MB caused a rapid and transient increase in pulmonary arterial blood pressure. Histological examination of lungs and liver from these animals showed a greater accumulation of MB in liver than in lung, in which virtually no MB was observed by light microscopy. The relative amounts of MB in lung and liver were measured by atomic emission spectrophotometry in animals given MB alone and following ENDO pretreatment. In either case the total amount of MB retained by the lungs was less than 2% of the injected dose, whereas liver retention of MB was approximately 88% in those birds given MB alone and 80% in those pretreated with ENDO. The results of this study suggest that chickens do not possess reactive pulmonary intravascular macrophages (PIMS), as, in those species in which reactive PIMS are present, injection of MB alone causes a marked increase in pulmonary arterial blood pressure and substantial lung retention of the tracer.