Whether or not the previously reported O3-induced abnormality in the postnatal development of tracheal secretory function in lambs is accompanied by changes in epithelial cell populations and their glycoconjugate composition was determined. Six lambs were killed at birth and 12 lambs at age 2 weeks. Of the latter 12, six were exposed to O3 (1 ppm, 4 hours daily for 5 days during the 1st week of life) and five had air-sham exposures (controls). Tracheal glycoconjugates were localized in situ with lectins to detect N-acetyl-galactosamine (gal-NAc), α-D-galactose (α-gal), β-D-gal (1 ← 3)-gal-NAc (β-gal), and fucose (fuc). Mean (± SD) epithelial cell density (cells/mm basal lamina) was 418 ± 57 in the newborns, 385 ± 63 in controls (P was not significant), and 342 ± 47 in O3-exposed lambs (P < 0.05). Mucous cell density was 87 ± 12 in newborns, 63 ± 10 in controls (P < 0.05), and 76 ± 10 in O3 exposed lambs (P was not significant). Ciliated cells remained unchanged from birth to 2 weeks (P was not significant), but decreased (P < 0.05) in O3-exposed lambs. All counted mucous cells contained fuc and galNAc at birth and retained these residues after sham and O3 exposure. The α-gal-containing mucous cells declined from 97 ± 13 to 7 ± 1 (P < 0.05) and β-gal containing cells from 39 ± 5 to 25 ± 4 in controls. In contrast, cells containing α-gal 71 ± 10 remained at newborn levels (97 ± 13) and β-gal-containing cells increased from 40 ± 5 at birth to 58 ± 8 in O3-exposed animals (P < 0.05). It was concluded that early postnatal exposure of lambs to O3 causes a decrease in epithelial cell density, but retards the developmental decrease in the number of tracheal mucous cells and alters the lectin detectable carbohydrate composition of mucus in these cells. These developmental defects were interpreted to be the morphologic correlates of the previously shown effects of O3 on the maturation of secretory function and mucus transport.
|Original language||English (US)|
|Number of pages||9|
|Journal||American Journal of Pathology|
|State||Published - 1989|
ASJC Scopus subject areas
- Pathology and Forensic Medicine