Changes in pulmonary surface tension and tumor necrosis factor-α after oleic acid induced lung injury during acute hyposia

Objective:To investigate changes in pulmonary surfactant system after oleic acid induced lung injury with acute hypoxia and their potential mechanism(s).Methods:A rat model of acute lung injury was produced by injected oleic acid into the superior vana cava.The levels of tumor necrosis factorα(TNFα) were measured both in bronchoalveolar lavage fluid(BALF) and plasma.Pulmonary surface tension was determined in BALF by KDⅡ instrument.Phosphalidylcholine (PC) and phosphatidylethanolamine (PE) levels were detected in BALF by high performance liquid chromatography.Results:TNFα levels were significantly increased in BALF and plasma,which kept gradually elevation along with the prolonged acute lung injury.PC levels were markedly decreased while PE levels significantly increased following oleic acid challenge.Also,the value of minimum surface tension kept a high level,but stable index and surface area showed persistent decrease and maintained low values.Treatment with pentoxifylline (PTX) markedly reduced pulmonary infiltration of inflammatory cells and inhibited TNFα formation both in BALF and plasma.Conclusions:Remarkable changes in PC,PE,and surface tension could be noted in animals with ARDS or acute lung injury.TNFα might not only involve in the pathogenesis of acute lung,but also impair pulmonary surfactant system.PTX can improve PaO 2 and attenuate pulmonary edema,and also decrease TNFα levels in BALF and plasma,showing beneficial effect on the treatment of acute lung injury during acute hypoxia.