Protein expression of MMP-2/9 and TIMP-1/2 in lungs of silicosis rats

Objective To investigate the expression of matrix metalloproteinase(MMP-2/9) and tissue inhibitor of matrix metalloproteinase(TIMP-1/2) protein in silica-induced pulmonary fibrosis rats and its significance.Methods Sixty-four Wistar rats were randomized into control group and silica group.The rats were intratracheally injected with silica to establish the pulmonary fibrosis model in silica group,and the rats were given the same dose of saline by the same way in control group.After injection for 3,7,14 and 28 d,the rats were killed and lungs were collected.Histopathological changes of the lungs were observed.The protein expression of MMP-2,MMP-9 and TIMP-1,TIMP-2 was determined by enzyme-labeled immunosorbent assay.Results Compared with control group,the lung tissues presented with local lesions,broadened alveolar wall and septum,swelled interstitial cells,and local cellular nodules in pulmonary alveolar cavity in silica group at 3 d.At 28 d,the alveolar structures were damaged or disappeared in silica group and parts of the alveolar spaces were collapsed and replaced by collagens and fibroblasts.The protein expression of MMP-2,MMP-9,TIMP-1,and TIMP-2 in silica group was significantly higher than that in control group(P0.05).Conclusion The results suggest that the MMP-2,MMP-9,TIMP-1,and TIMP-2 protein may be involved in the development of silica-induced lung injury fibrosis.