Endotoxin Suppresses Surfactant Synthesis in Cultured Rat Lung Cells

Pulmonary complications secondary to postburn sepsis are a major cause of death in burned patients. Using an in vitro organotypic culture system, we examined the effect of E. coli endotoxin (LPS) on lung cell surfactant synthesis. Our results showed that E. coli endotoxin (1.0, 2.5, 10 μg LPS/ml) was capable of suppressing the incorporation of ‘H-choline into de novo synthesized surfactant, lamellar bodies (LB), and common myelin figures (CMF) at 507c, 68%, and 64%, respectively. In a similar study, we were able to show that LPS also inhibited H-palmitate incorporation by cultured lung cells. LPS-induced suppression of surfactant synthesis was reversed by hydrocortisone.Our results suggest that LPS may play a significant role in reducing surfactant synthesis by rat lung cells, and thus contribute to the pathogenesis of sepsis-related respiratory distress syndrome (RDS) in burn injury.