Evaluation of Bronchiolar and Alveolar Cell Injuries Induced by Short- and Long-term Exposure to Sidestream Smoke

Abstract

BackgroundWe investigated effects of short- and long-term exposure to sidestream smoke on the bronchiolar and alveolar cells in Sprague-Dawley rats.MethodsRats 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.ResultsLM 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.ConclusionsSidestream smoke causes a bronchiolar and alveolar cell injury and the severity correlates strongly the volume and duration of exposure to sidestream smoke.

Ultrastructural changes of lung tissue under conditions of experimental obesity and smoking

“…Magnani et al (2012) described changes in the lung tissue corresponding to those we observed in this study, in particular, degenerative changes of alveolocytes, as well as the presence of thin, disorganized collagen fibrils in the interalveolar membranes with the formation of aggregates (bundles) in various areas of the interstitium [13]. According to a study by Kwon et al (2012), exposure to varying volumes of tobacco smoke can cause similar changes in the respiratory tract of experimental animals. These changes include a decrease in the number of epithelial cells, destruction of these cells, uneven distribution of secretory granules, and thickening of the bronchial walls [16].…”

“…According to a study by Kwon et al (2012), exposure to varying volumes of tobacco smoke can cause similar changes in the respiratory tract of experimental animals. These changes include a decrease in the number of epithelial cells, destruction of these cells, uneven distribution of secretory granules, and thickening of the bronchial walls [16]. Excessive collagenization can be seen as an early sign of exposure to tobacco smoke, which can later lead to pulmonary fibrosis.…”