Koslowski R, Dobbs L G, Wenzel K W, Schuh D, Müller M, Kasper M
Institute of Physiological Chemistry, Dresden University of Technology, Germany.
Eur Respir J. 1998 Dec;12(6):1397-403. doi: 10.1183/09031936.98.12061397.
After lung injury, the epithelial cells lining the alveolar surface in rat lung show an altered distribution of several membrane proteins. Pulmonary fibrosis was induced by intratracheal administration of bleomycin into the lung of rats and the distribution of RTI40, a recently detected alveolar epithelial type I cell antigen, was examined, as well as the relationship between RTI40 and a type I cell-specific antigen recognized by the monoclonal antibody MEP-1 and the type I cell-binding lectin Bauhinia purpurea in serial sections and double stainings. Loss of RTI40 protein was observed in fibrotic lungs, particularly in areas with obliteration of alveoli. Pre-embedding immunoelectron microscopy confirmed this observation by detection of RTI40 protein in the alveolar lumen. Western blot analysis revealed elevated levels of RTI40 in the bronchoalveolar fluid of bleomycin-treated rats with a maximum at day 7 after treatment. Twenty-eight days after bleomycin application, the bronchoalveolar fluid contained three times the amount of RTI40 x mg protein(-1) of control lungs, as determined by semiquantitative dot blot. These results suggest RTI40 as a tool for the evaluation of alveolar epithelial type I cell behaviour during re-epithelialization processes.
肺损伤后，大鼠肺脏肺泡表面的上皮细胞显示出几种膜蛋白分布的改变。通过向大鼠肺内气管内注射博来霉素诱导肺纤维化，并检测最近发现的肺泡I型上皮细胞抗原RTI40的分布，以及在连续切片和双重染色中RTI40与单克隆抗体MEP-1识别的I型细胞特异性抗原和I型细胞结合凝集素紫羊蹄甲之间的关系。在纤维化肺中观察到RTI40蛋白缺失，尤其是在肺泡闭塞区域。包埋前免疫电子显微镜通过检测肺泡腔内的RTI40蛋白证实了这一观察结果。蛋白质印迹分析显示，博来霉素处理的大鼠支气管肺泡灌洗液中RTI40水平升高，在处理后第7天达到最高。应用博来霉素28天后，通过半定量斑点印迹法测定，支气管肺泡灌洗液中RTI40的含量是对照肺的3倍（每毫克蛋白中含RTI40 x毫克）。这些结果表明RTI40可作为评估再上皮化过程中肺泡I型上皮细胞行为的一种工具。
