CYTOTOXIC EFFECTS OF SULFURIC-ACID MIST, CARBON PARTICULATES, AND THEIR MIXTURES ON HAMSTER TRACHEAL EPITHELIUM

Hamster tracheal tissue was used to study the effects of H2SO4 mist, carbon particles, and mixtures of the two on cilia beating frequency and morphological alterations of respiratory epithelium. Hamsters were exposed for 3 hr to 1.1 mg/m3 H2SO4 (mean size, 0.12 μm) and 1.5 mg/m3 carbon (mean size, 0.3 μm) particle aerosols alone or in combination. Trachea of animals exposed in vivo to the mixture and held in vivo showed cytotoxic effects in the epithelium that were greater than those produced by either the acid mist or carbon alone. In tracheas of hamsters exposed in vivo and maintained in vitro the damage produced by acid mist-carbon mixture did not differ significantly from that produced by acid mist per se but was greater than that observed after exposure to carbon. Organ cultures of tracheal rings exposed for 3 hr to a 1:106 dilution of concentrated H2SO4 and 100 μg/ml carbon produced epithelial damage in vitro similar to that seen in in vivo exposures. The extent of recovery over a period of 72 hr was also studied following different combinations of in vivo and in vitro exposure and/or maintenance. © 1979.