title: Evaluation of Bronchiolar and Alveolar Cell Injuries Induced by Short- and Long-term Exposure to Sidestream Smoke.
abstract: BACKGROUND
  We investigated effects of short- and long-term exposure to sidestream smoke on the bronchiolar and alveolar cells in Sprague-Dawley rats.
  
  
  METHODS
  RATS WERE DIVIDED INTO FIVE EXPERIMENTAL GROUPS: groups 1, 2, and 3 (1-month exposure to 3, 5, and 7 cigarettes a day, respectively), groups 4 and 5 (3- and 6 month exposure to five cigarettes a day, respectively). We examined the morphologic changes, the expressions of tumor necrosis factor α (TNF-α), tumor growth factor β1 (TGF-β1), interlekin (IL)-1α, IL-1β, Ki-67, and cytokeratin 14 and in situ apoptosis in the bronchiolar and alveolar cells on light microscopy (LM) and electron microscopic (EM) terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining.
  
  
  RESULTS
  LM showed the respiratory bronchiolar dilatation and alveolar wall collapse. In groups 3, 4, and 5, EM showed loss of the cilia and Clara cells with irregular size, more prominent alveolar wall collapse and dilation of alveolar duct than those of groups 1 and 2. Bronchiolar and alveolar cells showed increased expressions of TNF-α and TGF-β in groups 4 and 5. LM and EM TUNEL stains showed increased apoptosis in groups 3, 4, and 5.
  
  
  CONCLUSIONS
  Sidestream smoke causes a bronchiolar and alveolar cell injury and the severity correlates strongly the volume and duration of exposure to sidestream smoke.
authors.affiliation: Department of Pathology, Keimyung University School of Medicine, Daegu, Korea.
authors.forename: Kun-Young
authors.initials: KY
authors.lastname: Kwon
authors.forename: Hye-Ra
authors.initials: HR
authors.lastname: Jung
authors.forename: Ilseon
authors.initials: I
authors.lastname: Hwang
authors.forename: Won-Il
authors.initials: WI
authors.lastname: Choi
keywords: Alveolar cells; Bronchiolar cells; Immunohistochemistry; Sidestream smoke; TUNEL staining