Am. J. Respir. Cell Mol. Biol., Vol 11, No. 3, Sep 1994, 312-320.
Exposure to sidestream cigarette smoke alters bronchiolar epithelial cell differentiation in the postnatal rat lung
CM Ji, CG Plopper, HP Witschi and KE Pinkerton
Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California, Davis 95616.
This study examines the effects of an ambient concentration of aged and
diluted sidestream cigarette smoke (ADSS) on bronchiolar epithelial cell
development and the expression of cytochrome P450 isozyme 1A1 protein in
the postnatal rat lung. In control animals, the labeling indices for
epithelial cells in proximal bronchi and terminal bronchioles at 7 days of
age were 2.3 and 4.9%, respectively, and decreased to 0.1 and 0%, by 100
days of age. With exposure to ADSS from birth, the labeling index of
epithelial cells in distal airways of rats was significantly reduced at 7
and 14 days of age, but not in epithelial cells of 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
subsequently decreased to low levels at 50 and 100 days of age. In
contrast, exposure to ADSS significantly increased the distribution and
intensity of staining for 1A1 antigen in bronchiolar epithelial cells of
proximal and distal airways as early as 7 days of age and maintained
elevated levels of 1A1 protein in these cells through 100 days of age. At
21 and 50 days of age, NADPH reductase protein expression was higher in the
airway epithelium of rats exposed from birth to ADSS than that noted in the
airways of controls. In contrast, cytochrome P450 isozyme 2B and Clara cell
secretory protein expression were unchanged.(ABSTRACT TRUNCATED AT 250
WORDS)
