目的　探讨肠源性感染致早期肺损伤的作用机理。方法　采用大鼠盲肠结扎并穿孔 (CLP)造成腹腔感染。检测肺毛细血管通透性 ,取支气管肺泡灌洗液 (BALF)进行细胞学分析 ,检测血浆、肺组织和BALF的内毒素和肿瘤坏死因子 (TNF)。结果　肺毛细血管通透性和BALF的中性粒细胞百分率逐渐增加 ,时间越长越明显。血浆、肺组织和BALF的内毒素逐渐增加 ,三者之间两两显著相关 ;TNF也逐渐增加 ,肺组织和BALF的TNF显著相关 ,两者与血浆的TNF无明显相关性。结论　腹腔感染导致肺组织中内毒素增加 ,中性粒细胞积聚 ,TNF释放 ,肺产生炎性反应。 Objective To investigate the mechanism of intestinal infection caused by early lung injury. Methods The caecal infection was induced by cecal ligation and perforation (CLP) in rats. Permeability of pulmonary capillaries was measured. Bronchoalveolar lavage fluid (BALF) was taken for cytological analysis to detect endotoxin and tumor necrosis factor (TNF) in plasma, lung tissue and BALF. Results Pulmonary capillary permeability and BALF neutrophil percentage gradually increased, the longer the more obvious. Endotoxin in plasma, lung tissue and BALF gradually increased, and there was a significant correlation between them in any two groups; TNF also increased gradually, and TNF in lung tissue and BALF were significantly correlated. There was no significant correlation between them and plasma TNF. Conclusion Intraperitoneal infection leads to increased endotoxin, accumulation of neutrophils, release of TNF, and inflammatory reaction in the lungs.