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Updated: Jun 18, 2026
In Vivo Assessment of Alveolar Macrophage Efferocytosis Following Ozone Exposure
Published on: October 22, 2019
[Effect of SiO2 on expression of MMP-9/TIMP-1 in human alveolar macrophages in vitro]
Li Zhang1, Xiao-Hui Hao, Xian-Hua Wang
1Tianjin Union Medicine Centre, Tianjin 300121, China.
Objective:
To investigate the effect of SiO2 on the expression of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) in human silicotic alveolar macrophages (AM).
Methods:
Human alveolar macrophages were collected from a silicotic patient by bronchoalveolar lavage and exposed to silicon dioxide for 3 h, 6 h, 12 h, 18 h, 24 h and 36 h. The expression of the MMP-9 in the AM were detected with zymography and immunological method and the expression of the TIMP-1 in the AM with immunological method.
Results:
The expressions of MMP-9 in the AM increased clearly along with the time, reached peak at 24 h when detected with zymography (average optical density: 3.061+/-0.153 vs 2.851+/-0.164, P<0.05); and reached peak at 18h when detected with immunological method (average optical density: 0.386+/-0.037 vs 0.322+/-0.034, P<0.05). The expression of the TIMP-1 in the AM did not vary when detected with immunological method (P>0.05).
Conclusion:
SiO2 may affect the expression of MMP-9 and MMP-9 activity in the cultured AM.
Insights
Silicon dioxide (SiO2) exposure increases matrix metalloproteinase-9 (MMP-9) expression in human silicotic alveolar macrophages (AM) over time. Tissue inhibitor of metalloproteinase-1 (TIMP-1) expression remained unchanged.
Area of Science:
- Pulmonary Medicine
- Cell Biology
- Toxicology
Context:
- Silicosis is a lung disease caused by inhaling crystalline silica dust.
- Alveolar macrophages (AM) play a key role in the lung's response to inhaled particles.
- Matrix metalloproteinases (MMPs) and their inhibitors are involved in tissue remodeling and inflammation.
Purpose:
- To determine the impact of silicon dioxide (SiO2) on MMP-9 and TIMP-1 expression in human silicotic AM.
- To investigate the temporal dynamics of MMP-9 and TIMP-1 expression following SiO2 exposure.
Summary:
- Human silicotic AM were exposed to SiO2 for varying durations (3-36 hours).
- MMP-9 expression, measured by zymography and immunological methods, significantly increased over time, peaking at 18-24 hours.
- TIMP-1 expression showed no significant change in response to SiO2 exposure.
Impact:
- SiO2 exposure modulates MMP-9 expression and activity in AM.
- Findings suggest a role for MMP-9 in the pathogenesis of silicosis.
- Further research may explore therapeutic strategies targeting MMP-9 in silicosis.
