Acute secretory cell toxicity and epithelial exfoliation after smoke inhalation injury in sheep: An electron and light microscopic study

Sam Jacob, Robert Kraft, Yong Zhu, Reuben K. Jacob, David N. Herndon, Daniel L. Traber, Hal K. Hawkins, Robert A. Cox

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


Smoke inhalation injury promotes exfoliation of the upper airway columnar epithelium. Tracheal tissues from sheep 30min after smoke exposure show intact epithelial areas, areas of epithelial disruption with loss of columnar cells and areas denuded of columnar cells. In intact areas detaching ciliated cells can be seen raised above the apical surface. This study aims to assess cell-specific toxicity by examining intact epithelium after inhalation injury. The junctional adhesion integrity between columnar and basal cells and the type of cells initially being displaced were also studied using light (LM) and transmission electron microscopy (TEM). TEM assessment of intact areas of sheep tracheal tissue (n3) 30min after exposure showed secretory cell toxicity including extrusion of cytoplasmic contents. In cells with severe secretory cell cytoplasmic disruption, loss of desmosomal junctions between the secretory and adjacent ciliated cells was evident. The number of desmosomes visible between columnar cells and basal cells was reduced (2.8 ± 1.8) in smoke-exposed animals compared to those in uninjured animals (5.0 ± 2.7), p0.008. Serial sections of intact regions found 52 cells being displaced from the epithelium. All detaching cells were identified as ciliated cells. These studies show that the acute effects of inhalation injury include selective secretory cell toxicity which is associated with loss of junctional adhesion mechanisms and displacement of ciliated cells. Improved understanding of acute hypersecretory responses and epithelial integrity after exposure to toxic agents may improve understanding of epithelial fragility in airway disease.

Original languageEnglish (US)
Pages (from-to)504-509
Number of pages6
JournalToxicology Mechanisms and Methods
Issue number8
StatePublished - Oct 2010


  • Airway
  • Airway disease
  • Electron microscopy
  • Epithelium
  • Exfoliation
  • Hypersecretion
  • Inhalation injury
  • Secretory cells
  • Toxicity

ASJC Scopus subject areas

  • Toxicology
  • Health, Toxicology and Mutagenesis


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