DNA single strand breaks(SSB)in lung cells of children and adults exposed to urban pollution with high ozone concentrations

Ozone(03), an aggressive air pollutant 8 a strong oxidizing agent, is present all year long in Southwest Metropolitan Mexico City(SWMMC),03 maximal average daily concentrations≥250 ppm. Exposure to this atmosphere rapidly induces DNAssb in the nasal respiratory epithelium of exposed subjects(EHPFeb96).We assessed ssb in induced sputum from SWMMC children & young males exposed daily to ≥ 7h outdoors. Results were compared with a control population: 8 children& 15 adult males living in a low-polluted Caribbean Island. SSB were assessed by the Single Cell Gel Electrophoresis Assay(SCGE) (Singh et al, Exp Cell Res 175: 184, 1988) in sputum-induced material(Faby et al,Am Rev Resp Dis 147: 1126, 1993).The sputum had 87;10.1% alveolar macrophages(AM). SCGE re.sults:control children & adults had 82% normal cells & ssb in X16.7% of lung cells with minimal DNA migration(<40u). Significant increases in ssb were seen in exposed children(#16) & adults(#13)with ≥70% of cells with ssb(p<0.0001)& DNA migration up to 120u.DNA ssb are induced in children & adults lung cells, mainly alveolar macrophages, upon exposure to the polluted atmosphere. DNA damaged AM may play a crucial role in the lower respiratory tract responses after prolonged & daily 03 exposures and more importantly might participate in the long term development of chronic lung disorders specially in young children with outdoor physical activities.No Grant support.