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Morphological changes in rat lung parenchyma exposed to low frequency noise.
N R Grande1, A P Aguas, A De Sousa Pereira
1Abel Salazar Institute for the Biomedical Sciences, University of Porto, Portugal.
Aviation, Space, and Environmental Medicine
|April 3, 1999
Summary
Long-term exposure to large, low-frequency noise (LPALF) caused pulmonary fibrosis in rats. This suggests that LPALF noise may be a risk factor for lung disease in humans, even without other inhaled toxins.
Area of Science:
- Environmental Health
- Pulmonary Medicine
- Toxicology
Background:
- Airway flow limitation observed in aeronautical technicians exposed to long-term large pressure amplitude and low frequency (LPALF) noise.
- Subpleural fibrosis identified in rat pleura exposed to LPALF noise environments.
Purpose of the Study:
- Investigate the effects of LPALF noise on deep lung parenchyma in rodents.
- Determine if LPALF noise exposure leads to pulmonary fibrosis.
Main Methods:
- Wistar rats exposed to LPALF noise for 4000h and 5000h.
- Control group of rats kept in silent conditions.
- Lung parenchyma processed for light and electron microscopy.
Main Results:
- Focal interstitial fibrosis and changes in bronchial cilia observed in noise-exposed rats.
- Increased brush cells with abnormal microvilli.
- Increased alveolar type II pneumocytes with prominent lamellar bodies.
Conclusions:
- Noise-exposed rats showed altered extracellular matrix and epithelial cells compared to controls.
- No evidence of fuel exhaust, vapors, or dust in the exposure environment.
- LPALF noise is strongly suggested as an agent causing pulmonary fibrosis, linking to human respiratory disorders.
