Background The aim of this study was to prospectively study the changes in neutrophil elastase (NE), flbroblast growth factor 9 (Fgf9), matrix metalloproteinase-9 (MMP-9), tissue inhibitor of metalloproteinase 1 (TIMP-1) in sputum induced during the early period after lung volume reduction surgery (LVRS).Methods From April to October 2005, ten consecutive patients with chronic obstructive pulmonary disease (COPD) underwent LVRS. Ten non-small cell lung cancer patients (stage II-Illa) received Iobectomy as a control group. The induced sputum was collected from beth groups at six different times (two weeks before operation and postoperatively at 1, 2, 4, 6 and 10 days). The level of NE, Fgf9, MMP-9 and TIMP-1 were measured using enzyme-linked immunosorbent assay.Results The pulmonary function (FEV1%) and arterial blood gases (PaO2 and PaCO2) were significantly different between the groups. There were no significant differences in age, ejection fraction (EF), and operation duration, but hemoglobin in the LVRS group was statistically higher than in the controls. At certain times, there were significant differences in NE, MMP-9, TIMP-1 and MMP-9/I"IMP-1 (P