Induction of Secondary Apoptosis, Inflammation, and Lung Fibrosis After Intratracheal Instillation of Apoptotic Cells in Rats

Details

• Personal Author:
  Antonini JM ; Castranova, Vincent ; Mercer RR ; Rojanasakul Y ; Scabilloni JF ; Wang LY
• Description:
  Uncontrolled apoptosis has been associated with several pulmonary disorders; however, the molecular mechanism underlying this process and the fate of apoptotic cells in vivo are unclear. Here we show that direct administration of apoptotic cells to the lungs of rats caused pulmonary inflammation and fibrosis, as indicated by emigration of inflammatory cells to the air spaces, TNF-alpha immunoreactivity, and connective tissue accumulation, indicating a direct relationship between apoptotic cells and the observed lung pathologies. To determine how the lungs process the accumulated apoptotic cells, normal or apoptotic cells from autologous donor rats were labeled with fluorescent nanobeads and intratracheally instilled into the lungs of rats. Probe distribution and lung cell apoptosis were determined at various times over a 28-day period by confocal fluorescence microscopy and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling, respectively. Labeled apoptotic cells were cleared by lung macrophages within 1 wk after the treatment. However, the total number of apoptotic cells in the lung remained high at 28 days posttreatment. The results indicate a continuous induction of secondary apoptosis by apoptotic cell instillation, which may contribute to the observed lung pathology. Analysis of lung cell apoptosis by caspase assays showed an elevation of caspase-8 but not caspase-9 in the treatment group at 28 days posttreatment, indicating involvement of the death receptor-mediated pathway in the apoptotic process. Together, our results demonstrate a direct effect of apoptotic cell accumulation on inflammatory and fibrotic pulmonary responses and the continuous induction of lung cell apoptosis by apoptotic cell instillation. [Description provided by NIOSH]
• Subjects:
  Animals Fibrosis Laboratories Lung Lung Diseases Occupational Health Respiratory System Respiratory Tract Diseases Safety
• Keywords:
  Animal-studies Fibrogenesis Fibrogenicity Laboratory-animals Lung-disorders Lung-fibrosis Pulmonary-system-disorders Respiratory-system-disorders
• ISSN:
  1040-0605
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  290
• Issue:
  4
• NIOSHTIC Number:
  nn:20030039
• Citation:
  Am J Physiol Lung Cell Mol Physiol 2006 Apr; 290(4):L695-L702
• Contact Point Address:
  L. Wang, National Institute for Occupational Safety and Health, 1095 Willowdale Rd., Morgantown, WV 26505
• Email:
  lmw6@cdc.gov
• Federal Fiscal Year:
  2006
• NORA Priority Area:
  Work Environment and Workforce: Emerging Technologies
• Peer Reviewed:
  True
• Source Full Name:
  American Journal of Physiology: Lung Cellular and Molecular Physiology
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:02a03cc9eabb0938ec1a198790eea525382a39c59619826fa1413712e8a847bba4aeaa8bd0b9b14c4d8c1ec31ede6f77fae0c80dfb44ec6ca62802b4c86229d1
• Download URL:
  https://stacks.cdc.gov/view/cdc/190894/cdc_190894_DS1.pdf
• File Type:
  [PDF - 1.27 MB ]