ANTIOXIDANT PROPERTIES OF GUINEA-PIG TRACHEAL EPITHELIAL-CELLS IN-VITRO

Guinea pig tracheal epithelial (GPTE) cells in primary air/liquid inte rface culture were exposed to H2O2, and the rate of H2O2 consumption b y apical and basolateral surfaces was measured. GPTE cells had potent H2O2 scavenging ability, with faster consumption of H2O2 from the apic al surface. Inhibition of catalase (Cat) with sodium azide (NaAz) sign ificantly attenuated the ability of GPTE cells to remove higher concen trations of H2O2 Depletion of reduced glutathione, the substrate for g lutathione peroxidase (GPO), with DL-buthionine-[S,R]-sulfoximine (BSO ) did not affect consumption of K2O2. Dissolution of mucus from the ce lls reduced scavenging activity of the cultures and basement membrane/ extracellular matrix material (BM/ECM) deposited by the cells demonstr ated significant H2O2-scavenging activity. The results suggest that GP TE cells retain antioxidant capability in vitro when cultured in an ai r/liquid interface. This capacity to scavenge H2O2 appears to rely on Cat, as well as an mucus and BM/ECM material. However, a significant a mount of H2O2 scavenging appears to depend on other, yet unidentified, antioxidant system(s).