INDUCTION OF SISTER-CHROMATID EXCHANGES (SCE) IN HUMAN TRACHEAL EPITHELIAL-CELLS BY THE FRACTIONS PM-10 AND PM-2.5 OF AIRBORNE-PARTICULATES

Recent epidemiological studies in the United States and in Europe indi cate, that the coarse fraction (PM-10) of airborne particulates, small er than 10 mu m and particularly the fine fraction (PM-2.5) smaller th an 2.5 mu m are responsible for adverse health effects, causing an inc reasing morbidity and mortality. Furthermore, an association was repor ted between air pollution, especially the levels of the fine respirabl e particles and death from lung cancer. The epithelium of the respirat ory tract is the major target of airborne particulates and the locatio n of the most common cancer in man, bronchogenic carcinoma. The genoto xic activity of the coarse (PM-IO) and the fine fraction (PM-2.5) of a irborne particulates leading to mutation and cancer can be analyzed us ing in vitro models of human bronchoepithelial cells. In our study col lection of the coarse (PM-IO) and the fine fraction (PM-2.5) of airbor ne particulates was conducted in the winter of 1996 in the highly indu strialized Rhine-Ruhr region (Germany). For collection we selected an urban area (Dusseldorf), an industrialized area Duisburg and a rural a rea (Borken). Airborne particulates were collected with a Low Volume M -10 dichotomous sampler (Graseby-Andersen) equipped with glass fiber f ilters. Chemical substances were extracted from filters with di-chloro methane and quantitatively transferred to dimethylsulfoxide (DMSO). As target cells for testing the genotoxic activity we used cultures csf the human bronchioepithelial cell line (BEAS-2B). As a sensitive cytog enetic endpoint for evaluation of the;genotoxic activity of extracts o f airborne particulates we utilized the induction of 'sister chromatid exchanges' (SCE). The coarse fraction PM-IO and especially the fine f raction PM-2.5 of airborne particulates from all three locations cause d a strong dose-related induction of 'sister chromatid exchanges'. The fine fractions PM-2.5 from the three locations exerted a stronger gen otoxic activity than the corresponding coarse fractions PM-10. While a irborne particulates from Dusseldorf and Duisburg revealed a comparabl e genotoxic activity, the samples from Borken disclosed a lower genoto xicity. It is important that especially the fine fraction PM-2.5, exer ted a strong genotoxicity equivalent to substances of airborne particu lates from less than 0.5 m(3) of air. Results of this study and earlie r reports demonstrate that the human tracheobronchial epithelial cell line (BEAS-2B) in vitro offer a reliable and sensitive in vitro model for genotoxicity testing of airborne particulates, especially of the c oarse (PM-IO) and fine fraction (PM-2.5). (C) 1998 Elsevier Science Ir eland Ltd. All rights reserved.