Objective: To evaluate the role of matrix metalloproteinases-9 (MMP-9) and tissue inhibitor of metalloproteinases-1 (TIMP-1) in the pathogenesis of chronic obstructive pulmonary disease (COPD).
Methods: Five milliliters of peripheral venous blood were extracted form 36 patients with COPD, subdivided into stable group (CS group, n = 12), exacerbation group (CE group, n = 12), and exacerbation group with glucocorticosteroids treatment (CE + G group, n = 12), and 12 normal controls. The peripheral blood mononuclear cells (PBMCs) were isolated and the mRNA expressions of MMP-9 and TIMP-1 therein in each group were measured by RT-PCR quantitative analysis. The MMP-2 and MMP-9 levels in the plasma were studied by gelatin zymography. The relationship between MMP and pulmonary function was evaluated.
Results: (1) The MMP-9 mRNA expression and MMP-9: TIMP-1 ratios in the samples obtained from patients with COPD were higher in comparison with those from the control group (all P < 0.05). (2) The MMP-9 levels in plasma were higher in the COPD groups than in the control group (P < 0.05). (3) In the COPD groups, the MMP-9 mRNA expression, MMP-9: TIMP-1 ratio, and MMP-9 level in plasma were negatively correlated with FEV(1.0)% of prediction (r = -0.789, P < 0.05; r = -0.53, P < 0.05; and r = -0.652, P < 0.05), and positively correlated with RV/TLC% (r = 0.375, P < 0.05; r = 0.44, P < 0.05; and r = 0.529, P < 0.05).
Conclusion: MMP-9 and the imbalanced ratio of MMP-9: TIMP-1 may not only play a role in the pathogenesis of COPD, but also relate to FEV(1.0)% of prediction and RV/TLC%.