Failure of ozone and nitrogen dioxide to enhance lung tumor development in hamsters

Journal Article · Wed Sep 01 00:00:00 EDT 1993 · Research Report Health Effects Institute; (United States)

OSTI ID:5506027

Witschi, H; Breider, M A; Schuller, H M ^[1]

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1. Univ. of California, Davis, CA (United States)

We tested the hypothesis that the two common oxidant air pollutants, ozone and nitrogen dioxide, modulate the development of respiratory tract tumors in Syrian golden hamsters. The animals received subcutaneous injections of the carcinogen diethylnitrosamine (20 mg/kg) twice a week while being exposed continuously to an atmosphere of 0.8 parts per million (ppm)* of ozone or 15 ppm of nitrogen dioxide. Animals were killed 16 weeks or 24 to 32 weeks after the beginning of the treatment. Ozone delayed the appearance of tracheal tumors and reduced the incidence of tumors in the lung periphery. A suspected neuroendocrine differentiation of those lung tumors could not be established by immunocytochemistry due to overfixation of tissues. On the other hand, ozone seemed to mitigate development of hepatotoxic lesions mediated by diethylnitrosamine. In animals treated with diethylnitrosamine and exposed to nitrogen dioxide, fewer tracheal tumors and no lung tumors were found. Only a few lung tumors were produced in animals treated with diethylnitrosamine and kept in an atmosphere of 65% oxygen. The previously observed neuroendocrine nature of tumors induced by simultaneous exposure to diethylnitrosamine and hyperoxia could not be established because the long fixation of tissues precluded immunocytochemical stains. Animals treated with diethylnitrosamine and kept in filtered air while being housed in wire-mesh cages developed fewer lung tumors than animals given the same treatment and kept on conventional bedding in shoebox cages. Although all inhalants tested are known to produce substantial cell proliferation in the respiratory tract, it was not possible to document whether this would enhance lung tumor development. The role of the two common air pollutants, ozone and nitrogen dioxide, as possible additional risks in the pathogenesis of lung cancer in animals continues to remain uncertain.

• OSTI ID: 5506027
• Journal Information: Research Report Health Effects Institute; (United States), Vol. 60; ISSN 1041-5505
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
59 BASIC BIOLOGICAL SCIENCES
LUNGS
NEOPLASMS
PATHOGENESIS
NITROGEN DIOXIDE
RESPONSE MODIFYING FACTORS
OZONE
HAMSTERS
ANIMALS
BODY
CHALCOGENIDES
DISEASES
MAMMALS
NITROGEN COMPOUNDS
NITROGEN OXIDES
ORGANS
OXIDES
OXYGEN COMPOUNDS
RESPIRATORY SYSTEM
RODENTS
VERTEBRATES
560300* - Chemicals Metabolism & Toxicology
550900 - Pathology