Preneoplastic transformation of rat tracheal epithelial cells by ozone

Journal Article · Sat Jun 01 04:00:00 EDT 1991 · Toxicology and Applied Pharmacology; (United States)

DOI:https://doi.org/10.1016/0041-008X(91)90197-M· OSTI ID:5395300

Thomassen, D G; Harkema, J R; Stephens, N D; Griffith, W C ^[1]

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1. Inhalation Toxicology Research Institute, Lovelace Biomedical and Environmental Research Institute, Albuquerque, NM (USA)

The transforming potency of ozone for rat tracheal epithelial (RTE) cells exposed in vivo or in vitro was determined. RTE cells isolated from rats exposed to ozone (0, 0.14, 0.6, or 1.2 ppm, 6 hr/day, 5 days/week for 1, 2, or 4 weeks) showed no increase in the frequency of preneoplastic transformation compared to cells isolated from unexposed rats, although ozone-induced morphologic changes were observed in exposed tracheas. In contrast, preneoplastic variants of RTE cells were induced by multiple, but not single, exposures of RTE cells to ozone in culture. RTE cells exposed biweekly to ozone ({approximately} 0.7 ppm for 40 min, nine total exposures) had approximately two fold increases in the frequency of preneoplastic transformation compared to that of concurrent controls exposed to air. Single, 40-min exposures to ozone ({approximately} 1 or {approximately} 10 ppm) did not induce preneoplastic variants. However, single, 40-min exposures of RTE cells to {approximately} 10 ppm ozone did result in {approximately} 40% decreases in colony-forming efficiency. In addition, single, 40-min exposures of RTE cells to {approximately} 1 ppm ozone reduced the transforming potency of a subsequent exposure to the direct-acting chemical carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). When multiple ozone exposures followed exposure to MNNG ({approximately} 0.7 ppm ozone for 40 min, nine biweekly exposures), an additive (or possibly a multiplicative) effect of ozone on MNNG-induced preneoplastic transformation was seen. These results demonstrate that ozone can, under some conditions, induce preneoplastic variants of RTE cells. In addition, depending on the sequence or combinations of exposures, ozone can reduce or, possibly, increase, the transforming potency of the carcinogen MNNG for rat tracheal cells in culture.

• OSTI ID: 5395300
• Journal Information: Toxicology and Applied Pharmacology; (United States), Journal Name: Toxicology and Applied Pharmacology; (United States) Vol. 109:1; ISSN TXAPA; ISSN 0041-008X
• Country of Publication: United States
• Language: English

Related Subjects

560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL TISSUES
ANIMALS
BODY
CARCINOGENESIS
CELL DIVISION
CELL TRANSFORMATIONS
EPITHELIUM
INHALATION
INTAKE
MAMMALS
NITROSO COMPOUNDS
ONCOGENIC TRANSFORMATIONS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OZONE
PATHOGENESIS
RATS
RESPIRATORY SYSTEM
RODENTS
SYNERGISM
TISSUES
TRACHEA
VERTEBRATES