Comparative Study Of Different Intratracheal Instillation In Acute Lung Injury Model Of Mice

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are clinical syndromes induced by both pulmonary and extrapulmonary stimuli and characterized by the excessive inflammatory response, destroy of alveolar-capillary integrity and severe disruption for pulmonary gas exchange. So far, the pathogenesis of ALI/ARDS is unknown. Because no other specific therapy is available except for protective mechanical ventilation, ALI/ARDS are still associated with a high mortality (about 50%).It is pretty necessary for the further study of acute lung injury to set up and evaluate the animal models. The improvement of the acute lung injury animal models is helpful to reveal its pathogenesis and raise its efficiency of diagnosis and therapy. The successful establishment of animal models is due to the definite ways of administration. So far, intratracheal instillation of endotoxin has been mainly used to set up the acute lung injury models by domestic and foreign scientists. According to the exposure of trachea or not, there are non-exposed and exposed intratracheal instillation. However, scanty information has existed on the objective and systemic evaluation of these two methods of intratracheal instillation up to now. ObjectiveTo compare the non-exposed and exposed intratracheal instillation in acute lung injury models of mice induced by endotoxin and attempt to confirm which method is much better.Materials and methods45 healthy male C57BL/6 mice were randomly divided into three groups: Control group, Non-exposed group and Exposed group, 15 mice per group. The ALI models of mice in Non-exposed and Exposed groups were established by non-exposted and exposted intratracheal instillation of endotoxin respectively. The success rates of two intratracheal instillation were compared. Meanwhile, BALF biochemical indicators and differential cell counting, the lung wet/dry (W/D) weight ratio and pathological examination were demonstrated in each group. Statistics of all data were conducted by SPSS PASW Statistics 18.Results1. The success rate of Non-exposed group was 86.7%~93.3%, and the Exposed group was 100%.2. BALF biochemical indicators, the amount of neutrophils in BALF, the lung wet/dry (W/D) weight ratio in Exposed group were significantly higher than the Non-exposed group.3. The pathological change of Non-exposed group was characterized by pulmonary interstitial edema, but the Exposed group was exudative pulmonary edema.Conclusion1. The exposed intratracheal instillation had the higher success rate in establishing the ALI model of mice compared with the non-exposed one.2. The acute pulmonary inflammation induced by the exposed intratracheal instillation was more severe, characterized by exudative pulmonary edema, and may copy the detailed procedure of ALI.3. The exposed intratracheal instillation was more effective in establishing the ALI model of mice compared with the non-exposed one.Creation point1. It was the first time to perform the objective and systemic evaluation of these two methods of intratracheal instillation.2. The exposed intratracheal instillation was proved to be more suitable for establishing the ALI model of mice induced by endotoxin which provides the solid basis for the further study of ALI/ARDS.