Fly ash‐induced changes in hamster tracheal epithelium in vivo and in vitro

Abstract

The effects of fly ash from a coal‐fired power plant on tracheal epithelium of CrRGH (SYR) Syrian golden hamsters were studied in organ cultures and after in vivo exposures. The trachéal epithelium of animals receiving 5–9 daily (5 d/wk) 3‐h exposures to 2 mg fly ash per cubic meter showed large areas of basal cell hyperplasia and stratification. Surface alterations characteristic of stratified metaplasia were observed. Exposure to 1 mg/m³ produced diffuse basal cell hyperplasia. Hamster tracheal ring cultures exposed in vitro to 50 μg/ml fly ash for 1 h/d or to 10 μg/ml for 3 h/d showed epithelial changes similar to those observed in vivo. Whole suckling hamster tracheas in organ culture exposed to fly ash at concentrations of 10 and 50 μg/ml for 1 or 3 h/d exhibited cornifying epidermoid metaplasia after 7 exposures. The most characteristic findings in surface cells were broad metaplastic areas with keratin formation.