Abstract: Objective　To investigate the phenotypic change of macrophages in lung tissue during the development of hepatopulmonary syndrome (HPS).　Methods　The HPS model was induced by multiple pathogenic factors in Sprague-Dawley rats and divided into HPS groups of the 4th week，the 6th week and the 8th week. Normal control groups at the corresponding time points were also set up. Liver and Lung tissue histology was observed by HE staining. VG staining method was used to observe the liver fibrosis. Immunofluorescence method was used to observe the macrophage marker (CD68). The expressions of M1/M2 macrophage markers (CD86 and CD206) were detected by real-time PCR assay, while the expressions of corresponding secretions iNOS, TNF-α, Arg-1 and IL10 were detected by Elisa.　Results　With the progress of the disease, the expression of CD86, iNOS and TNF-α gradually increased in the lung tissue of model group. After reaching the peak in the 6th weeks, CD86 and iNOS fell back. While the expression of CD206, Arg-1 and IL10 began to increase significantly at the 6th week. There was a positive correlation between iNOS and CD86 in the lung tissue of the model group. Arg-1 was positively correlated with CD206. IL10 was positively correlated with CD206.　Conclusions　During the pathogenesis of HPS, macrophages in lung tissue underwent a series of phenotypic changes, with M1 predominating at 6 weeks and M2 predominating at 8 weeks.   

Key words: Hepatopulmonary syndrome, 　Macrophages, 　M1, 　M2