EFFECTS OF CIGARETTE-SMOKE ON THE GLUTATHIONE STATUS OF THE UPPER ANDLOWER RESPIRATORY-TRACT OF RATS

Endogenous antioxidants, like the tripeptide glutathione (GSH), protec t the respiratory airways from potentially injurious agents within inh aled pollutants like cigarette smoke. The purpose of this study was to determine the effects of cigarette smoke exposure on respiratory trac t tissue. Twenty-four F344/N male rats were exposed to cigarette smoke (249 mg total particulate matter/m(3)) or filtered air for 6 h/day fo r 9 days. Rats were sacrificed 1 day or 14 days after the last exposur e. The most dramatic changes in GSH concentrations occurred in the tis sues of the nasal cavity 1 day following exposure, with tissues from t he proximal nasal airways showing the greatest response. These same pr oximal nasal airway tissues also had the greatest histopathological ch anges. Within 2 wk after exposure, the GSH concentrations in the nasal tissues from smoke-exposed rats were similar to air-exposed controls, and there was only minimal histopathological evidence of tissue alter ation. GSH concentrations were not significantly elevated in the left extrapulmonary bronchi or main axial airway, nor were there any histol ogic alterations evident in these tissues at any time point. Thus, the extent of the cellular GSH response paralleled the extent of respirat ory tract tissue injury and recovery. Our results suggest that the rea ctive agent(s) in cigarette smoke cause increased GSH in nasal tissue and that squamous metaplasia occurs in nasal surface epithelium. Both changes, however, are resolved by 14 days after a short-term cigarette smoke exposure.