A method for establishment of rat model with pulmonary contusion / 中华创伤杂志

ABSTRACT

Objective To create an easy and specific rat model of isolated bilateral pulmonary contusion and determine the maximal sublethal injury energy.Methods Injury energy was produced by free falling weights and passed through a designed precordial shield to rats' bilateral posterolateral chest wall.The rats were divided into 2.1 J,2.4 J,2.7 J and 3.0 J groups,according to the volume of injury energy.Percentage of lung contusion volume in bilateral lung was measured by blood gas analysis and three dimensional CT (3DCT) at four hours post-injury to assess lung injury severity after contusion.Pathological examination of heart and lung tissue was performed to confirm pulmonary contusion and rule out myocardial contusion.Results Death rate in 3.0 J and 2.4 J groups was 33％ and 11％,respectively.PaO2 in 2.7 J group was significantly lower than that in 2.4 J group (P ＜ 0.01),but pulmonary contusion percentage in 2.7 J group was significantly higher than that in 2.4 J group (P ＜0.01).All groups showed negative correlation between PaO2 and pulmonary contusion percentage measured by 3DCT (R2 =0.762).Hemorrhage,atelectasis and neutrophil infiltration were documented in lung biopsy.No evidence of myofiber break was recorded in heart biopsy.Conclusion This method can duplicate satisfactory models of isolated bilateral pulmonary contusion and 2.7 J can be regarded as the maximal sublethral injury energy.