The establishment of pulmonary acute lung injury model in rats

Abstract

Objective To establish pulmonary acute lung injury(ALI)model in rats.Methods ALI model was induced in rats by intratracheal Escherichia coli injection[3 ml/kg,O111B4,(4.0～6.0)×1012 CFU/L].Mechanical ventilation was applied 12,24,36,48 and 72 h after Escherichia coli injection,PaO_2/FiO_2 and dynamic compliance were recorded,and the normal control group was also subjected to mechanical ventilation.After the experiment,lungs were fixed with formalin to perform pathological examination.Results At 12,24,36,48 and 72 h,the PaO_2/FiO_2 were(30.71±7.95)kPa,(21.66±5.34)kPa,(21.09±4.75)kPa,(25.01±8.78)kPa and(33.82±8.02)kPa,respectively,which were significantly lower than that in the normal control group(63.82±3.03)kPa(P＜0.01).At 12,24,36,48 and 72 h,the Cdyn were(4.23±0.13)ml/(kg·kPa),(4.19±0.96)ml/(kg·kPa),(4.28±0.69)ml/(kg·kPa),(4.44±0.62)ml/(kg·kPa)and(4.58±0.35)ml/(kg·kPa)respectively,which were significantly lower than that in the normal control group(8.16±0.78)mL/(kg·kPa)(P＜0.01).At 12,24,36,48 and 72,the percentage of ALI was 71.4%,100.0%,100.0%,83.3%and 57.1%respectively,and the percentage of ARDS was 28.6%,85.7%,83.3%,66.7%,14.3%respectively.As for pathological examinations,predominance of alveolar collapse,fibrinous exudates,alveolar wall edema and neutrophil recruitment into the alveolar space was observed.Hyaline membrane formation was found.At 72 h,inflammation was relieved.Conclusion We successfully established pulmonary ALI/ARDS model in rats induced by intratracheal Escherichia coli injection,and acquired some useful information by observing the lung function and morphological changes at different time points. Key words: Acute lung injury; Escherichia coli; Animal model