Effect of antioxidant on pulmonary surfactant in acute lung injury rats

Abstract

Objective To explore the changes of neutrophil elastase (NE) and surfactant protein A (SP-A) in acute lung injury(ALI) rats,and the effect of antioxidant. Methods Sixty healthy mature Wister rats were divided into 2 groups, the control group and treatment group. The rats in two groups all received peritoneal injection of E. coli to establish the ALI animal model. 30 minutes after injection of E. coli,the rats in treatment group were injected reduced glutathione from vena caudalis. The levels of NE in blood and expressions of SP-A in lung tissue were detected at 3,6 and 12 hours after injection of E. coli. Results ALI symptom appeared 3 hours after injection of E. coli in the control group, obvious after 6 hours, the rats vomi-ted pink secretion after 12 hours. Lung edema and bleeding were found by pathologic examination. No obvious symptom was found in treatment group after 3 hours, slight tachypnea after 6 hours, slight edema in pulmonary tissue after 12 hours. After administration of reduced glutathione,levels of NE at 3,6 and 12 hours in the treatment group were lower than those in the control group,and indicated statistical significance in 6 and 12 hours(P <0. 05) ;Levels of SP-A in 3,6 and 12 hours in the treatment group were higher than those in the control group, and indicated statistical significance in 3,6 and 12 hours (P < 0. 05). Conclusion Dysfunction of pulmonary surfactant is secondary in ALI, degradation of SP-A is the one of reasons, the application of reduced glutathione as antioxidant, could effectively suppress NE to decompose basosexine elastin of cells and destroy surface active protein, has protective effect on ALI. Key words: Acute lung injury; Neutrophil elastase; Pulmonary surfactant protein A; Anti-oxidant; Rat