Abstract: Objective To investigate the influence of cigarette smoke on lung function and serum cytokine levels in chronic obstructive pulmonary disease (COPD) rats which were established by the complex stimulation of lipopolysaccharide (LPS) and smoked cigarettes. Methods Seventy-two male SD rats were randomly divided into six groups, 4 weeks, 6 weeks and 8 weeks model group, 3 weeks and 6 weeks natural healing group, and control group. A COPD rat model was established by the complex stimulation of two times LPS injection and smoked cigarettes. The lung function of the rats was measured during passive smoking and quit smoking. At the same time serum interleukin-8(IL-8), IL-10 and tumour necrosis factor-alpha (TNF-〈) levels were monitored by Enzyme-linked immunosorbent assay. Correlation analysis concerning cytokine levels and pulmonary function index were conducted. Results Compared with control group, forced expiratory volume in 0.3 second (FEV_0.3), forced expiratory volume in 0.3 second as a percentage of forced vital capacity (FEV_0.3/FVC) and IL-10 were decreased (P<0.05), IL-8 and TNF-〈 levels were increased in the model groups (P<0.05). And as the building time prolonged, the changes of those cytokines and lung function indexes were more obvious than before. IL-8 and TNF-〈 levels were inversely associated with FEV_0.3/FVC(P<0.001, r=-0.579; P=0.034, r=-0.354). Compared with control group, IL-8 and TNF-〈 levels were decreased in the 6 weeks healing group, at the same time IL-10 levels was increased(P<0.05), the FEV_0.3 and FEV_0.3/FVC were decreased in the healing groups (P<0.05). Conclusions Cigarette smoke is the primary cause of changes on cytokine levels in this animal model.

Key words: Chronic obstructive pulmonary disease (COPD), Cytokines, Animal model, Cigarette smoke