The study of experimental model of acute respiratory distress syndrome in rats induced by two-damage of lipopolysaccharide

Objective:To establish a rat model of acute respiratory distress syndrome by intratracheal instillation of lipopolysaccharide (LPS) after 16 hours of LPS intraperitoneal administration.Methods:18 male SD rats were randomly divided into two groups:(1)LPS group: LPS was intratracheally instillated (1 mg, 0.5 ml) after 16 hours of LPS intraperitoneal administration(1mg/kg).(2)control group: LPS was replaced with the same volume of saline. Hemodynamics and gas extrange were observed every 0.5 hour. After1.5 hours of ARDS, the rats were killed by hemorrhage from carotid artery.Results:After(2.33±1.56 h)hours of LPS instillation, ALI model was successfully replicated in 8 rats conforming to ARDS criteria. Compared with the base value, oxygernation index significantly decreased at the time of ARDS and 0.5, 1.0, 1.5 hours after ARDS (P 0.01). There was also a significant difference in oxygernation index between LPS group and control group (P 0.01). In the LPS group, PaCO 2 significantly increased at the time of ARDS and 0.5, 1.0, 1.5 hours after ARDS compared with the basic values and the control group (P 0.01). However, there was no significant difference in hemodynamics in LPS group,and there was no significant difference between LPS group and control group either(P0.05).Conclusion:We conclude that it is practical and stable ARDS rat model by intratracheal instillation of lipopolysaccharide (LPS) after 16 hours of LPS intraperitoneal administration.