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Updated: Oct 4, 2026
A Silicosis Mouse Model Established by Repeated Inhalation of Crystalline Silica Dust
Published on: January 6, 2023
Increased expression of matrix metalloproteinase in Clara cell-ablated mice inhaling crystalline silica
K Yatera1, Y Morimoto, H N Kim
1Department of Respiratory Disease, University of Occupational and Environmental Health, Kitakyushu City, Fukuoka Prefecture, Japan. yatera@med.uoeh-u.ac.jp
Abstract:
We investigated the function of Clara cells in vivo during exposure to inhaled crystalline silica by examining pulmonary matrix metalloproteinase (MMP)-2 and MMP-9 mRNA levels in mice. The Clara cells of male FVB/n mice (8-12 weeks old) were ablated by intraperitoneal administration of naphthalene (300 mg/kg) in a corn oil vehicle. The mice were then exposed to crystalline silica (Min-U-Sil-5 silica, 97.1 +/- 9.5 mg/m(2), 6 hr/day, 5 days/week) for up to 2 weeks. Transcriptional levels of mRNA extracted from the lungs were assessed by reverse transcription-polymerase chain reaction. Gene expression of both MMP-2 and MMP-9 was significantly more marked in the Clara cell-ablated group than in the group with Clara cells, indicating that Clara cells inhibit MMP expression. Our findings suggest that Clara cells inhibit pulmonary inflammation induced by crystalline silica via MMPs in vivo.
Insights
Clara cells inhibit pulmonary inflammation. Studies show these cells reduce matrix metalloproteinase (MMP) expression in mice exposed to crystalline silica, suggesting a protective role against lung injury.
Area of Science:
- Pulmonary toxicology
- Cell biology
- Immunology
Background:
- Clara cells are crucial for lung repair and defense.
- Crystalline silica exposure can induce significant pulmonary inflammation.
- Matrix metalloproteinases (MMPs) play a role in inflammatory processes.
Purpose of the Study:
- To investigate the role of Clara cells in regulating pulmonary inflammation during crystalline silica exposure.
- To examine the effect of Clara cell ablation on MMP-2 and MMP-9 expression in the lungs.
Main Methods:
- Male FVB/n mice underwent Clara cell ablation using naphthalene.
- Mice were exposed to crystalline silica for up to two weeks.
- Pulmonary MMP-2 and MMP-9 mRNA levels were quantified using reverse transcription-polymerase chain reaction.
Main Results:
- Clara cell-ablated mice showed significantly higher MMP-2 and MMP-9 mRNA levels compared to control mice.
- This indicates that Clara cells normally suppress MMP expression in the lung.
- The findings suggest Clara cells play an inhibitory role in silica-induced pulmonary inflammation.
Conclusions:
- Clara cells exert an inhibitory effect on pulmonary matrix metalloproteinase expression.
- These cells may protect the lungs from inflammation induced by inhaled crystalline silica.
- Targeting Clara cell function could be a potential therapeutic strategy for silica-induced lung diseases.
