Changes of alveolar epithelial permeability after acute lung injury in rats and effects of terbutaline on it

Objective To observe the changes of alveolar epithelial permeability(AEP) and effects of terbutaline on it in oleic acid induced lung injury in rats.Methods Wistar rats were randomized into 3 groups: the control(C), injured group(OI) and terbutaline treated group(T). Lung injury was induced by intravenous oleic acid(0.25ml/kg). In terbutaline treated group, terbutaline solution(1×10 -4 Mol/L, 5ml/kg) was instilled into the trachea after injury. The alveolar epithelail permeability(AEP), total lung water content(TLW), extravascular lung water content(EVLW) and pulmonary content of cAMP were examined at 12h and 24h after injury.Results After lung injury, there was continuous increase of AEP,TLW and EVLW, as well as progressive reduction of the pulmonary content of cAMP. In terbutaline treated group, AEP,TLW and EVLW were much lower than those of non-treated rats, but still higher than those of control group. In addition, terbutaline significantly increased pulmonary content of cAMP.Conclusion The alveolar epithelial permeability enlarged greatly after oleic acid indueced lung injury in rats. Terbutaline inhibited the enlargement of alveolar epithelial permeability, the mechanism of which was related to the elevation of cAMP.