Study of pulmonary surfactant and surfactant protein in rats with LPS-induced acute lung injury

Objective:To study the alteration trend of pulmonary surfactant(PS) and surfactant-associated protein(SP) in rats with LPS-induced acute lung injury(ALI).Methods:Fifty-six adult Wistar rats were randomly divided into normal saline(NS) group and ALI group.The levels of mRNA of the SP-A,SP-B were measured by reverse transcription polymerase chain reaction(RT-PCR) during iv LPS at 1,3,5,7h.The content and component of PS in the bronchoalveolar lavage fluid (BALF) were measured by high performance liquid chromatography (HPLC).In addition,studies on lung dry/wet weight ratio,the protein content of BALF,alveolar oxygen partial pressure (PaO 2)and histological changes were performed.Results:Compared with the NS group,ALI group developed severe lung damage.Edema,hemorrharge and inflammatory changes were found.Total phospholipids (TPL) of BALF at 1,3,5,7h were lower than those in the NS group( P 0.05);phosphatidylcholine(PC) at 3,5,7h were lower than those in the NS group( P 0.05);while lysophosphatidylcholine (LPC) at 1,3,5 ,7h were higher than thosein the NS group(P 0 .0 5 ) .Theexpression ofSP -A ,SP -Bm RNAat 3,5 ,7h were less than thosein the NSgroup(P 0 .0 5 ) .Conclusion :The changed metabolism of PSex ists in the pathogenesisn of ALI,which is mainly de monstratedas that the decreasein TPL ,PC ,will de crease expression of SP -A ,SP -Bm RNA .Decreasein content and changein components of PS may play an important role in severe hypoxemia in ALI .