烟雾吸入伤后肺表面活性物质蛋白A含量的动态变化及意义

目的探讨烟雾吸入伤后肺表面活性物质蛋白Ａ（ＳＰ－Ａ）含量的变化、可能机理及其与肺表面活性物质（ＰＳ）活性抑制和肺功能损害的关系。方法采用大鼠烟雾吸入伤模型，分别检测正常对照及致伤２ｈ、６ｈ、１２ｈ和２４ｈ动物的动脉血气，肺水量，静态肺顺应性（Ｃｓｔ），支气管肺泡灌洗液（ＢＡＬＦ）表面张力特性，ＢＡＬＦ中ＳＰ－Ａ、丙二醛（ＭＤＡ）、总蛋白（ＴＰ）含量及弹性蛋白酶（Ｅｌａ）活性。结果动物伤后出现急性呼吸衰竭和肺水肿，Ｃｓｔ显著降低；ＢＡＬＦ的最小表面张力（ＳＴｍｉｎ）升高，滞后环面积下降；ＢＡＬＦ中ＳＰ－Ａ、ＭＤＡ、ＴＰ含量及Ｅｌａ活性明显升高，但ＳＰＡ－Ａ的相对含量（％ＴＰ）降低，且与Ｅｌａ、Ｃｓｔ和ＳＴｍｉｎ的变化相关显著。结论烟雾吸入伤早期ＳＰ－Ａ相对含量减少，可能是导致肺表面活性物质活性抑制及肺功能障碍的主要原因之一。氧化及Ｅｌａ可能是引起ＳＰ－Ａ含量和（或）功能异常的重要因素。

Dynamic changes and significance of pulmonary surfactant protein A content after smoke inhalation injury.

Objective To investigate the dynamic changes and possible mechanisms of pulmonary surfactant protein A(SP A), and to evaluate the relationship between these changes and the pulmonary surfactant(PS)activity inhibition, as well as pulmonary dysfunction after acute lung injury caused by smoke inhalation. Methods Following the induction of smoke inhalation injury in rats, the arterial blood gas levels, lung water volume, static lung compliance(Cst), surface tension properties of bronchoalveolar lavage fluid(BALF), the contents of SP A,malondialdehyde(MDA), total protein and the activity of elastase(Ela) in BALF were determined respectively in normal control and injured animals at 2 h,6 h,12 h and 24 h after injury. Results After smoke inhalation, animals showed acute respiratory failure and serious pulmonary edema. The Cst decreased markedly. The minimum surface tension(ST min )of BALF increased, while its hysteresis area decreased progressively.The contents of SP A, MDA,TP and the activity of Ela in BALF increased dramatically. However, the relative content(%TP)of SP A decreased significantly with pronounced correlation between its change and the changes of Cst and ST min , as well as Ela. Conclusion The changes of SP A content occur at the early stages after smoke inhalation injury, and the decrease of SP A relative content is one of main causes to induce PS activity inhibition and pulmonary dysfunction. The oxidation and degradation of SP A may be important factors to result in its abnormal content and/or functions.