Deoxyribonucleic acid strand breaks caused by ozone and nitrogen dioxide in rat lung cells

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1991

OSTI ID:5109301

Bermudez, E

Toxic effects of O{sub 3} and NO{sub 2}, the major oxidants of photochemical smog, are mediated in part by free radical mechanisms. The present study was undertaken to determine if an exposure to O{sub 3} PIUS NO{sub 2} would cause a damage to lung cellular DNA. Three-month old male Sprague-Dawley rats, free of specific pathogens, were exposed to either 1.2 ppm NO{sub 2} or 0.3 ppm O{sub 3} alone, or a combination of the two oxidants continuously for 3 days. The oxidant effects were substantiated by determining total and differential cell counts, lactate dehydrogenase activity and total soluble protein in bronchoalveolar lavage. DNA damage was measured as single-strand breaks (SSB) by alkaline elution assay. The activation of poly (ADP-ribose) synthetase activity was used as an indicator of DNA repair. The results showed that, relative to control, NO{sub 2} exposure at 1.2 ppm did not cause any significant change in the parameters studied. Exposure to 0.3 PPM O{sub 3} and combined exposure to O{sub 3} and NO{sub 2} caused significant changes in all the parameters studied except cell viability. The changes for the combined exposure were synergistic for some of the parameters such as the number of polymorphonuclear neutrophil (PMN), the percentage of PMNs and pulmonary alveolar macrophage (PAM), and activity of poly(ADPR) synthetase. For the other parameters the increase was additive relative to the effects of O{sub 3} or NO{sub 2} alone. Exposure to O{sub 3} and NO{sub 2} increased the frequency of DNA-SSB in lung cells. This damage induced DNA repair process as shown by an increase in the poly(ADPR) synthetase activity which was synergistic with the combined exposure.

• Research Organization: California Univ., Los Angeles, CA (United States)
• OSTI ID: 5109301
• 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 CELLS
ANIMALS
BIOLOGICAL EFFECTS
BIOLOGICAL MATERIALS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
BLOOD
BLOOD CELLS
BODY
BODY FLUIDS
CHALCOGENIDES
CONNECTIVE TISSUE CELLS
DNA
DNA REPAIR
ENZYME ACTIVITY
ENZYMES
GENETIC EFFECTS
HEMIACETAL DEHYDROGENASES
LACTATE DEHYDROGENASE
LAVAGE
LEUKOCYTES
LIGASES
LUNGS
MACROPHAGES
MAMMALS
MATERIALS
NEUTROPHILS
NITROGEN COMPOUNDS
NITROGEN DIOXIDE
NITROGEN OXIDES
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANS
OXIDES
OXIDOREDUCTASES
OXYGEN COMPOUNDS
OZONE
PHAGOCYTES
PROTEINS
RADICALS
RATS
REPAIR
RESPIRATORY SYSTEM
RODENTS
SENSITIVITY
SOMATIC CELLS
STRAND BREAKS
SYNERGISM
VERTEBRATES