免疫受损大鼠铜绿假单胞菌肺部感染后rn肺表面活性物质的改变

摘要

Objective　To analyze the alterations of pulmonary surfactant in immunocompromised host with Pseudomonas aeruginosa(PA) pneumonia. Methods　50 rats were randomly divided into two groups， one immunosuppressed with cyclophosphamide and cortisone acetate as ICH group， another as control group(CON)， their lung tissue and bronchoalveolar lavage fluid(BALF) were collected before PA challenging and 3 h，6 h，9 h，24 h after PA challenging intratracheally，wet/dry ratio (W/D) of lung tissue were measured，concentrations of total protein(TP)，total phospholipids (TPL)，disaturated phosphatidylcholine (DSPC) and surfactant protein A(SP-A) in BALF were analyzed. Results　The ratios of DSPC/TPL and DSPC/TP decreased significantly in both ICH and CON groups after PA infection，there were not significant differences between the two groups，no change in the concentrations of TPL and DSPC. Concentration of SP-A and SP-A/TP in ICH group decreased remarkably 6 h after PA pulmonary infection than before［（1.8±1.1） μg/ml vs (4.2±1.5) μg/ml， （1.4±0.7） μg/mg vs （11.7±8.1) μg/mg， P<0.05］，meanwhile there were no significant alterations in CON group. W/D and TP concentrations increased in both groups after PA challenging， however the alterations were much greater in ICH group (P<0.05). Alterations of SP-A appeared a negative correlation with alterations of TP and W/D (r=-0.793， P<0.01，r=-0.769， P<0.01). The ratios of SP-A/TPL and SP-A/DSPC decreased significantly 6　h after PA challenging than before， the ratios were much lower in ICH group than in CON group during 6 h-9 h after PA inoculation. Conclusion　After PA pulmonary infection，alterations of phospholipids could initially appear a relative decrement of DSPC during acute phase of infection， much remarkable decrease of SP-A in ICH group could be associated with the more severe lung injury，alterations of SP-A were more obvious than surfactant lipids in ICH.%目的了解免疫受损宿主肺部铜绿假单胞菌（PA）感染后肺表面活性物质(PS)的改变。方法建立免疫受损宿主肺部PA感染的大鼠模型，同时设置对照组，在接种PA前后不同时间行左侧支气管肺泡灌洗，测定灌洗液中的总蛋白(TP)、总磷脂(TPL)、饱和磷脂酰胆碱(DSPC)、肺表面活性物质蛋白(SP-A)及右侧肺组织湿/干比。结果感染PA后，大鼠支气管肺泡灌洗液(BALF)中TPL及DSPC较感染前并无明显改变，但DSPC/TPL、DSPC/TP下降；免疫受损大鼠SP-A和SP-A/TP在感染前与对照组差别无显著性，但感染后下降明显，分别由感染前的（4.1±1.2）μg/ml、（22.5±5.0）μg/mg下降至接种后6 h的（1.8±1.1）μg/ml、（1.4±0.7）μg/mg（P<0.05），低于同期对照组大鼠水平［分别为（4.2±1.5）μg/ml，（11.7±8.1）μg/mg，P<0.05］，免疫受损大鼠TP及湿/干比升高更明显，两组大鼠SP-A与TP、湿/干比的改变呈负相关；免疫受损大鼠BALF中SP-A/TPL、SP-A/DSPC较感染前下降，感染后6 h达最低，且感染后6～9 h比例明显低于同期对照组。结论免疫受损大鼠PA肺部感染时，磷脂改变表现为DSPC/TPL、DSPC/TP降低，SP-A的下降与肺损伤严重程度有关，肺表面活性物质中磷脂与蛋白成分的改变不同步，SP-A下降幅度更明显。