To detect the levels of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) in the bronchoalveolar lavage fluid (BALF) and the serum of patients with idiopathic pulmonary fibrosis (IPF), and to evaluate the significance of the changes in the pathogenesis of IPF.
Enzyme-linked immunoadsorbent assay (ELISA) was used to detect MMP-9 and TIMP-1 in the BALF and serum of 30 patients with IPF.
The levels of MMP-9 in the BALF and serum of the patients showed no significant difference as compared with those of the control group. The levels of TIMP-1 in the BALF [(522 +/- 81) ng/L] and serum [(166 +/- 29) ng/L] of the patients were higher than those [(201 +/- 31), (87 +/- 16) ng/L] of the control group (P < 0.01). The ratios of MMP-9/TIMP-1 in the BALF (0.53 +/- 0.18) and serum (1.5 +/- 0.3) of patients with IPF were lower than those (1.06 +/- 0.38, 2.6 +/- 0.5) of the control group (P < 0.01, < 0.05). TIMP-1 in the BALF of the patients showed a strong positive correlation with chest CT fibrosis and pulmonary function test scores (P < 0.01), while MMP-9/TIMP-1 in the BALF had negative correlation with them (P < 0.01).
Pulmonary fibrosis may be associated with increased TIMP-1 and decreased MMP-9/TIMP-1, which is able to inhibit the degradation of extracellular matrix.