Effect Of Captopril On Ras With Hydrochloric Acid Inhalation Induced Acute Lung Injury

Objective The aim of this research was to observe the expressions of TNF-a in blood serum and blood gas analysis in artery in models of acute lung injury induced by hydrochloric acid inhalation and groups of interfere with captopril. Then we observed the pathological changes of lung under light microscope. The possible effects of captopril and its mechanism on rats with acute lung injury was expored.Method The model of acute lung injury(ALI) in ras was reproduced by dilute hydrochloric acid inhalation(PH=1.25,1.2ml/kg) according to Nader et al. Healthy adult Wister rats(weighing200-250g) were randomly divided into three groups(n=10each):Control group(group N), Acute lung injury group(group A), Captopril group(group C). Hydrochloric acid(PH=1.25,1.2ml/kg) was injected in tracheal catheter in rats of group A and group C, respectively.5minute later, captopril (5mg/kg) was used in group C with intraperitoneal injection.1.5h later, the samples were collected for immunohistochemistry (IHC) and ELISA. The observations were made about the expressions of TNF-α in serum, arterial blood gas and the lung tissue pathology change.Results Compared with group N, the expression of TNF-α increased significantly in group A and group C (p<0.05). And PaCO2increased significantly while PaO2decreased significantly in group A and group C. The expression of TNF-α decreased significantly in group C as compared with it in group A (p<0.05). PaCO2decreased significantly while PaO2increased significantly in group C as compared with them in group A. Under light microscope we can see that the structure of lung tissue is clear,the wall of alveolar is smooth and uniform,and neutrophilins rarely in group N. In group A we can see diffuse congestion and edema, the destroy of the structure,the thickening of the alveolar wall, massive neutrophil infiltration. In group C, mild edema of the lung tissue, the slightly thickening of the alveolar wall and a few neutrophils were in sight.Conclusion The expression of TNF-α increased in rats of acute lung injury, and meanwhile the PaCO2increased, PaO2decreased. Captopril could reduce the acute lung injury through the inhibitation of the expression of TNF-α.