应用光镜、电镜、图像分析仪观测了大鼠注射内毒素（Ｌ组）和氮芥＋内毒素（ＮＬ组）后１、３、５、１２、２４、４８、７２ｈ７个时相点的肺脏病理变化。发现Ｌ组肺组织充血、出血、水肿、肺萎陷；毛细血管内大量中性粒细胞（ＰＭＮ）和血小板滞留、嵌塞、崩解脱粒，内皮细胞肿胀、坏死；肺泡上皮退变，继而Ⅱ型肺泡上皮细胞增生等。病变过程表现为循环障碍、变性坏死和损伤修复３个阶段。先注射氮芥使大鼠外周血ＰＭＮ减少，再注射内毒素，发现肺脏病变延迟发生，且程度较Ｌ组明显减轻。表明ＰＭＮ在内毒素引起的肺损伤发展过程中起着重要作用 The lungs of rats at 1, 3, 5, 12, 24, 48 and 72 h after endotoxin injection (L group) and nitrogen mustard + endotoxin (NL group) were observed by light microscope, electron microscope and image analyzer Pathological changes. L group lung tissue congestion, bleeding, edema, lung collapse; a large number of capillary neutrophil (PMN) and platelet retention, cessation, disintegration threshing, endothelial cell swelling, necrosis; alveolar epithelial degeneration, and then Ⅱ Alveolar epithelial cell proliferation and so on. Lesions manifested as circulatory disorders, degeneration and necrosis and injury repair three stages. The first injection of nitrogen mustard PMN in peripheral blood of rats decreased, and then injected endotoxin, found that delayed onset of lung disease, and the degree of L group was significantly reduced. This indicates that PMN plays an important role in the development of endotoxin-induced lung injury