Establishment of a model of acute lung injure in aged rats

Objective To establish a model of acute lung injury (ALI) in aged rats for studying the pathogenesis of ALI in the elderly.Methods Two hundred and ten 24 month old rats were randomly divided into three groups( n=70) :oleic acid+lipopolysaccharide group (O+LPS group), oleic acid group (O group), lipopolysaccharide group (LPS group).O+LPS group received intravenous injection of 0.175 ml/kg oleic acid at first and intravenous injection of 2.5 mg/kg lipopolysaccharide eight hours later. O group and LPS group received intravenous injection of oleic acid or lipopolysaccharide respectively. After injection, all rats received 1.5 L/min oxygen therapy for four hours except the 1 h post injection group. At the time before intravenous injection and then at 1,6,12,24,72,120 h after injection, the PaO 2 was measured and pathological change of lung was examined. In addition, the incidence of systemic inflammatory response syndrom (SIRS) and ALI, mortality of each group were observed.Results The PaO 2 of O+LPS group was less than that of O group and LPS group ( P0.01) . The pathologic score of lung, incidence of SIRS and MODS, mortality of O+LPS group were higher than those of O group and LPS group( P0.01) .Conclusion It is successful to imitate the development of ALI after lung injury and secondary infection by injection of oleic acid and lipopolysaccharide subsequently. This is a suitable model for studying the pathogenesis of ALI in the elderly.