Protective Effect of Dexamethasone on the Lung Injury in Severe Acute Pancreatitis in Rats

Objective To investigate the protective effects of dexamethasone on the lung injury in severe acute pancreatitis(SAP).Methods Eighteen SD rats were randomly divided into 3 groups: sham operation group;SAP group,dexamethasone treatment group(with intravenous dexamethasone 1 mg/kg).SAP was induced by retrograde infusion of 5% sodium taurocholate into the bili-pancreatic duct in SD rats.Serum TNF-α and TNF-α mRNA,myeloperoxidase(MPO) in pulmonary homogenate were determined at 8 h after SAP induced.The weight ratio between the wet and dry lung tissue and pulmonary pathology were compared between the groups.Results In SAP group,serum TNF-αlevel(265.8±33.1 pg/ml) and pulmonary TNF-α mRNA content(0.93±0.07) and MPO activity(0.89±0.06 U/g) and the weight ratio between the wet and dry lung tissue(3.97±0.47) and pulmonary pathologic severity(2.87±0.26) were increased significantly.Administration of dexamethasone significantly reduced the serum TNF-α level(110.4±15.2 pg/ml),the pulmonary TNF-α mRNA content(0.43±0.06), MPO activity(0.54±0.04),the weight ratio between the wet and dry lung tissue(3.18±0.37) and pulmonary pathologic severity(1.51±0.18),compared with that in the SAP group(P0.01).Conclusion Therapeutic dexamethasone may be effective in improving acute lung injury in SAP,probably through the inhibition of SIRS and the activation of leukocytes.