TIMP1 and chronic obstructive pulmonary disease: In this study, the rats in the COPD group showed low weight growth, pulmonary functional and structural impairment, bronchiole stenosis, accumulation of neutrophils, induction of inflammatory cytokines in BALF and blood, increase of linear intercept and alveolar septal thickness, decrease of alveolar number, increase of the inflammatory cytokines expression in the lung, and imbalance between MMP-9 and TIMP-1 in the lung, which clearly suggest an animal model of COPD.