Objective:To investigate the expression of the collagenases MMP-13 and its inhibitor

tissue inhibitor metalloproteinase-1 (TIMP-1) in the rat lung of the experimental models of COPD.Methods:Male Wistar rats (10 weeks of age) were divided into two groups—model and control groups.The rat of model group were given intratracheal lipopolysaccharide (LPS)

and then animals were exposed to cigarette smoke for 32 days.The lung function was measured

and pathological changes were also observed.Transcriptional levels of MMP-13 and TIMP-1 mRNA extracted from the lungs were assessed by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR).Results:(1)In COPD model group

the pathological changes of bronchi and lung tissue

the changes of lung function were similar to those of the COPD patients.(2)The mRNA expression of MMP-13 and TIMP-1 in COPD model group were significantly increased compared with those in control group( P <0.01 or P <0.001).Conclusion:COPD is characterized by chronic obstruction of expiratory flow affection peripheral airways

associated with chronic bronchitis and emphysema

together with fibrosis and tissue damage

and inflammation of the small airways.MMP-13 and TIMP-1 might play important roles in chronic airway inflammation and remodeling of COPD.They may contribute to the process of pathogenesis

and development of COPD.