Expressions of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 in rat lung tissue and human vascular endothelial cells after cigarette smoke exposure.

Objective To study the expressions of matrix metalloproteinase-9(MMP-9)and tissue inhibitor of metalloproteinase-1(TIMP-1)in rat lung tissue and human vascular endothelial cells after cigarette smoke exposure.Methods The rat model of chronic obstructive pulmonary disease(COPD)was established by exposure to cigarette smoke.The general condition,lung function,pathological features,white blood cell count and classification in the bronchoalveolar lavage fluid(BALF),and expressions of MMP-9 and TIMP-1 in the lung tissue were determined in COPD group(group M)and control group(group N).Western blot was performed to detect the expressions of MMP-9 and TIMP-1 in the vascular endothelial cells exposed to different concentrations of cigarette smoke extract.Results The changes such as hair falling,dullness and rapid breathing appeared in the rats of group M.There were significant differences in the histomorphologic characteristics of the lung tissue,lung function,count of inflammatory cells in BALF,expressions of MMP-9 and TIPM-1,and ratio of MMP-9/TIMP-1 between groups N and M.The expressions of MMP-9 and TIMP-1 in the vascular endothelial cells increased with the concentration of cigarette smoke extract.Conclusion Smoking is one of the key pathogenic factors for COPD.The imbalance of MMP-9/TIMP-1 in the lung tissue and the expressions of MMP-9 and TIMP-1 in the vascular endothelial cells may play an important role in the pathogenesis of COPD.