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[Changes of matrix metalloproteinases activities in pulmonary fibrosis rats]
1Laboratory of Biochemistry and Molecular Biology, Capital Medical University, Beijing 100069, China. kongluxinxiang@sina.com.cn
Objective:
To observe the changes of matrix metalloproteinases (MMPs) activities in pulmonary fibrosis rats.
Methods:
Eighty male SD rats were randomly divided into sham group (n = 40) and bleomycin group (BLM, n = 40), in which SD rats were injected with a single intratracheal dose of sham saline or bleomycin respectively. On day 1, 3, 7, 14, and 28 following bleomycin or saline instillation, rats were randomly killed, and serum from abdominal aorta, alveolar fluid from the bronchoalveolar lavage, and the lung homogenate were collected and then stored at -80 degrees C. MMPs activity was determined by zymography.
Results:
Compared with sham group, the levels of MMP-9 in all samples were augmented. MMP-9 activities in the serum were highest on day 3 than those on day 1 and day 7, and in lung tissue homogenate were highest on day 7; however, no significant differences were found between BLM group and sham group on day 14 and day 28; and that of bronchoalveolar lavage fluid (BALF) was highest on day 7 than those on day 1 and day 14, while no significant difference existed between BLM group and sham group on day 28. Serum MMP-2 level did not change from day 1 to day 28, while the level of BALF MMP-2 began to increase after day 14, even on day 28. Lung tissue homogenate MMP-2 level began to increase early on day 3 and continued to day 28.
Conclusion:
The sources and effects of MMP-2 and MMP-9 differ in BLM-induced rat pulmonary fibrosis.
Insights
Matrix metalloproteinases-9 (MMP-9) and MMP-2 activities change differently in bleomycin-induced pulmonary fibrosis. MMP-9 levels peaked early, while MMP-2 levels increased later in rat models.
Area of Science:
- Biochemistry
- Pulmonary Medicine
- Animal Models
Context:
- Pulmonary fibrosis is a progressive lung disease with limited treatment options.
- Matrix metalloproteinases (MMPs) play crucial roles in tissue remodeling and inflammation.
- Understanding MMP dynamics is vital for developing targeted therapies.
Purpose:
- To investigate the temporal changes in matrix metalloproteinases-9 (MMP-9) and MMP-2 activities in a rat model of pulmonary fibrosis.
- To differentiate the roles and sources of MMP-2 and MMP-9 in bleomycin-induced lung injury.
Summary:
- Bleomycin-induced pulmonary fibrosis in rats showed distinct patterns of MMP-9 and MMP-2 activity.
- MMP-9 levels in serum, lung homogenate, and bronchoalveolar lavage fluid peaked at different early time points.
- MMP-2 levels exhibited delayed increases in bronchoalveolar lavage fluid and lung tissue.
Impact:
- This study highlights the differential kinetics of MMP-2 and MMP-9 in pulmonary fibrosis.
- Findings suggest distinct therapeutic windows for targeting specific MMPs in fibrotic lung disease.
- Provides a basis for further research into MMP-specific interventions for pulmonary fibrosis.
