Mucous cell metaplasia (MCM) in the respiratory tract of rats after exposure to cotton dust and machining fluid

Details

• Personal Author:
  Gordon T ; Harkema J
• Description:
  Increased sputum production and chronic bronchitis are associated with occupational exposure to bio-aerosols contaminated with endotoxin. The purpose of the present study was to determine if occupationally relevant concentrations of cotton dust and machining fluids can induce MCM in rat airways. F344 rats were exposed to: 1) filtered air or 1.5, 5.0, or 15.0 mg/m3 cotton dust for 2 h/d; or 2) aerosols of water or 1 or 10 mg/m3 machining fluids for 3h/d for 3 d and sacrificed at 24 h after the last exposure. Tissues from the proximal nasal septum and axial airway of the left lung lobe were processed and stained with AB/PAS to identify stored mucosubstances in the epithelium (ME). Significant increases in ME were evident in the nasal septum of rats exposed to 5.0 and 15.0 mg/m3 cotton dust (5.6 and 3.5 fold greater, respectively). Smaller, yet statistically significant increases in ME were also observed in the axial airways of these 2 groups of animals (1.6 and 2.2 fold greater, respectively). No changes in the amounts of ME were observed in the respiratory tract of rats exposed to 1.5 mg/m3 cotton dust compared to air controls. Similar to the MCM induced by cotton dust, exposure to 10 mg/m3 used machining fluids produced significant increases in ME in the nasal septum and axial airway (5-fold and 1-fold greater, respectively). Exposure to 10 mg/m3 unused machining fluids also induced a significant increase in ME in the nasal septum (4-fold), but not in the axial airway. No changes in the amounts of ME were observed in the respiratory tract of rats exposed to 1.0 mg/m3 used machining fluid. These studies suggest that while contaminating endotoxin may play a significant role in the increase in sputum and chronic bronchitis reported for workers exposed to organic dust and aerosols, other irritant factors in machining fluids participate in the induction of MCM in the respiratory epithelium of the nasal septum. [Description provided by NIOSH]
• Subjects:
  Aerosols Animals Dust Endotoxins Environmental Exposure Laboratories Lung Occupational Health Respiratory System Risk Assessment Risk Factors Safety

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• Keywords:
  Bioaerosols Bronchitis Cotton Dust Dusts Exposure Levels Laboratory Animals Organic Dusts Risk Factors Tissue Culture Workers
• ISSN:
  1073-449X
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Abstract or Summary
• Place as Subject:
  New Mexico ; New York ; OSHA Region 2 ; OSHA Region 6
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  149
• NIOSHTIC Number:
  nn:20048562
• Citation:
  Am J Respir Crit Care Med 1994 Apr; 149(Abstract Issue):A401
• Federal Fiscal Year:
  1994
• Performing Organization:
  New York University, New York, New York
• Peer Reviewed:
  False
• Start Date:
  19930901
• Source Full Name:
  American Journal of Respiratory and Critical Care Medicine
• Supplement:
  Abstract Issue
• End Date:
  20050929
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:b6c5e3a489119703736b3261c7d1edd92073e845869519f3171ca34f7dd8e23c6f5ae163517220af647fdad8f24cfcc3bb74eeb43a8ad8c2a873e89b1df520b8
• Download URL:
  https://stacks.cdc.gov/view/cdc/203287/cdc_203287_DS1.pdf
• File Type:
  [PDF - 1.15 MB ]