Exposure to sidestream cigarette smoke alters bronchiolar epithelial cell differentiation in the postnatal rat lung.
Ji-CM; Plopper-CG; Witschi-HP; Pinkerton-KE
Am J Respir Cell Mol Biol 1994 Mar; 11(3):312-320
The effect of exposure to aged and diluted sidestream cigarette smoke (ADSS) on bronchiolar epithelial cell differentiation was examined in postnatal rat lung. Sprague-Dawley-rats were exposed to ADSS for 6 hours per day, 5 days per week, from birth until day before sacrifice. Immunohistochemical studies were conducted on rats at 7, 14, 21, 50 and 100 days. A variety of functions were studied; these included proliferation, maturation, differentiation, and cytochrome-P450 isozyme 1A1 expression during critical periods of postnatal development and growth. In control animals, the labeling indices for epithelial cells in proximal bronchi and terminal bronchioles decreased with age; ADSS exposure accelerated this postnatal decrease of cell kinetic activity in epithelial cells of terminal bronchioles, but not in epithelial cells of the proximal bronchi. The expression of P450 isozyme 1A1 antigen in bronchiolar epithelial cells of control rats reached the maximal level observed at 21 days of age and then decreased; ADSS exposure accelerated and maintained expression of cytochrome-P450 isozyme 1A1 protein during postnatal lung development. NADPH reductase protein expression was higher in the airway epithelium of rats exposed to ADSS than in control animals at 21 and 50 days of age. ADSS exposure did not increase expression of cytochrome-P450 isozyme 2B or Clara cell secretory protein. The authors conclude that exposure of rats to ADSS from birth alters airway epithelial development; ADSS may increase the capacity for bioactivation of some airborne procarcinogens during lung development.
Tobacco-smoke; Lung-cells; Laboratory-animals; Cell-biology; Cell-differentiation; Cell-damage; Pulmonary-system; Developmental-disorders; Smoke-inhalation; Neonates
American Journal of Respiratory Cell and Molecular Biology
University of California - Davis