Changes of alveolar stability and phospholipids in pulmonary surfactant in acute pancreatitis

We investigated changes of alveolar stability and phospholipids in the pulmonary surfactant in case of acute pancreatitis induced in rats. Alveolar stability was examined by recording the pressure-volume relationship. The lung volumes during deflation decreased significantly at equivalent transpulmonary pressures, particularly when the pressure was lower than 6 cm H2O. Bubble stability ratio and surface tension indicated that the surface activity of the pulmonary surfactant did decrease in the rats with acute pancreatitis. The alveolar phospholipid content decreased, and the lecithin fraction also decreased significantly, as compared to the control groups. The metabolism of alveolar lecithin was examined following intravenous administration of 14C-labeled palmitate. The biological half-life of the radioactivity of alveolar lecithin was approximately 6 hours in the pancreatitis group, 12 hours in the hepatic ducts ligated group and 14 hours in the simple laparotomy group. The degradation of alveolar lecithin, as well as its synthesis, was accelerated in the rats with acute pancreatitis. However, a decrease in alveolar phospholipid, mainly in lecithin fraction, indicated that the synthesis was inadequate to maintain normal levels and the impairment in pulmonary surfactant may result in a respiratory insufficiency.