Abstract: Abstract：Objective To develop an "overlap syndrome (OS)" rat model by intermittent hypoxia (IH) exposure on the base of pre- existing emphysema, and to explore its characters of severe systemic inflammation and immune responses. Methods Sixty Wistar rats were put into four groups: control group, IH group, emphysema group and overlap (emphysema+ IH) group. The peripheral blood samples were collected for detecting apoptosis of CD3+ CD4+ ， CD3+ CD8+ T lymphocytes and neutrophils (PMN). Tumor necrosis factor (TNF)-α and interleukin (IL)-6 were evaluated by ELISA. The bronchoalveolar la⁃ vage fluid (BALF) was taken to calculate the ratio of macrophages, neutrophils and lymphocytes under light microscope. Tis⁃ sue blocks of lung, liver, pancreas, and right carotid artery were taken for pathologic scoring. Results The apoptotic rates of PMN and CD3 + CD8 + T cells were significantly lower in overlap group than those of other three groups (P < 0.05). Pro-in⁃ flammatory factor IL-6, TNF-α and peripheral blood CD3 + CD4 + T cell apoptosis were the highest in overlap group com⁃ pared to those of other three groups (P < 0.05). The ratio of PMN and macrophages in BALF were significantly higher in em⁃ physema group than those of other three groups (P < 0.05) and the pathology scores of lung, liver, pancreas, the ratio of carot⁃ id artery intima-media thickness of whole thickness of vascular were significantly higher in overlap group than those of other three groups (P < 0.05).Conclusion In rat model of intermittent hypoxia- emphysema there are more serious systemic multi-organ inflammation and immune responses.

Key words: emphysema, inflammation, immune, intermittent hypoxia, overlap syndrome