Pulmonary Apoptosis Of Acute Lung Injury In Burn Wound Sepsis Caused By Pseudomonas Aeruginosa

Objective To investigate the pulmonary apoptosis and observe the changes of lung of acute lung injury(ALI) in burn wound sepsis caused by Pseudomonas aeruginosa.Methods SPF SD rats were used as experimental animal ,and they were classified into 2 groups randomly. The test group were inoculated with Pseudomonas aeruginosa at the burn site immediately after the thermal injury to induce sepsis,while the control group were inoculated with saline at the burn site immediately after the thermal injury. At the time of 0,2,12 , 24 and 48 hours after inoculation , the rats were killed after injection of 1% Pentobarbital by 25mg/kg in abdominal cavity. Eschars were cutted off, and the amount of bacteria was counted. Lungs were fixed for haematoxylin and eosin(HE) stain. morphometrical tests were applied to assess lung histopathology changes in acute lung injury. Apoptosis was determined by TUNEL test ( Terminal deoxynucleotidyl transferase - mediated dUTP nick end labeling) and optical microscope, Apoptosis Index(AI) was calculated, and the correlation between the bacteria amount of the eschars and AI was analyzed.Results The bacteria amount of the eschars in test group exceeded the bacteria amount of the eschars in congtrol group at the same time,and the amount of bacteria increased over time. Interstitial edema occurred with massive infiltration of the inflammatory cells , alveolar spaces got more narrow,and the pulmonary architecture was damaged. The damage of lungs in test group was more serous than that in control group,and the damage of lungs aggravated over time. Morphometrical tests also showed that the damage of lungs in test group was more serous than that in control group. TUNEL test showed more positive cells compared with control group. AI reached the peak at 24hour.AI has linear correlation with the bacteria amount of eschars during 0-24hours.Conclusion In the early phase of ALI,AI increases with the aggravation of sepsis, and the damage of the lungs exacerbate with theaggravation of sepsis.