Sulfhydryl oxidation in rat nasal mucosal tissues after chlorine inhalation

Male F-344 rats were exposed to target concentrations of 2.5, 5, or 10 ppm Cl2 for various amounts of time, after which respiratory and olfactory nasal mucosal tissues were analyzed for changes in total sulfhydryl (TSH) content. No changes in olfactory mucosa TSH content were observed at the maximum Cl2 exposure. Decreases in content of respiratory mucosa TSH were seen after 6 hr exposures to 5 ppm and 10 ppm, but not 2.5 ppm. The concentration of TSH returned to control values 19 hr after termination of exposure. Analysis of TSH changes in concentration X time (CT) studies suggested that decreases in TSH were dependent on the airborne concentration of Cl2 and not on 'dose' (the CT product). The results suggest that inhaled Cl2 can oxidize tissue sulfhydryl groups at the point of entry, but not at deeper regions of the respiratory tract.