SENSITIVITY TO OZONE - COULD IT BE RELATED TO AN INDIVIDUALS COMPLEMENT OF ANTIOXIDANTS IN LUNG EPITHELIUM LINING FLUID

Ozone, though not a free radical species, mediates its toxic effects t hrough free radical reactions as a consequence of its high redox poten tial. Upon inspiration the first physical interface encountered by ozo ne is a thin layer of aqueous material, the epithelium lining fluid (E LF) which overlays, and is partially derived from, the underlying pulm onary epithelium. ELF is the first physical interface encountered by o zone and the majority of its primary actions are confined to this comp artment. ELF contains a range of antioxidants, including the small mol ecular weight antioxidants: uric acid (UA), ascorbic acid (AH(2)) and reduced glutathione (GSH). These compounds are present in large quanti ties and display high intrinsic reactivities toward ozone, consistent with their role as sacrificial substrates in this setting. In this pap er we examine the concept that antioxidants, in ELF, represent the fir st tier of defence against the oxidizing effects of ozone. Since the c oncentration of these antioxidants appears to differ between individua ls, we propose that these protective substances may dictate, in part, an individual's sensitivity to oxidizing air pollutants such as ozone.