Scanning electron microscopical investigations on the respiratory epithelium of the Syrian golde4n hamster. V. Dose-related in vitro effects of benzo(a)pyrene.

The biological effects of in vitro exposure of fetal hamster tracheal explants to three dose levels of benzo(a)pyrene (BaP:25, 50, 100 microgram/ml medium) in 0.5% dimethylsulphoxide (DMSO) were studied by light and scanning electron microscopy. A dose-related difference was seen in a quality of the observed pathological alterations in the specimens examined after 28 days of culture. Whilst in the explants treated with 50 or 100 microgram/ml BaP the respiratory epithelium revealed necrotic areas and extended metaplastic alterations, explants exposed to 25 microgram/ml BaP showed normal differentiation in some areas of the respiratory epithelium. In explants treated with the highest dose (100 microgram/ml BaP), hyperplastic foci were seen in the epithelium and tended to proliferate towards the tracheal lumen. These observations show similarity with early neoplastic alterations.