Long-term ozone exposure attenuates 1-nitronaphthalene-induced cytotoxicity in nasal mucosa

Gyong Lee Myong, Åsa M. Wheelock, Bridget Boland, Charles Plopper

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

1-Nitronaphthalene (1-NN) and ozone are cytotoxic air pollutants commonlyfound ascomponents of photochemical smog. The mechanism of toxicity for 1-NN involves bioactivation by cytochrome P450s and subsequent adduction to proteins. Previous studies have shown that 1-NN toxicity in the lung is considerably higher in rats after long-term exposure to ozone compared with the corresponding filtered air-exposed control rats. The aim of the present study was to establish whether long-term exposure to ozone alters the susceptibility of nasal mucosa to the bioactivated toxicant, 1-NN. Adult male Sprague-Dawley rats were exposed to filtered air or 0.8 ppm ozone for 8 hours per day for 90 days, followed by a single treatment with 0, 12.5, or 50.0 mg/kg 1-NN by intraperitoneal injection. The results of the histopathologic analyses show that the nasal mucosa of rats is a target of systemic 1-NN, and that long-term ozone exposure markedly lessens the severity of injury, as well as the protein adduct formation by reactive 1-NN metabolites. The antagonistic effects were primarily seen in the nasal transitional epithelium, which corresponds to the main site of histologic changes attributed to ozone exposure (goblet cell metaplasia and hyperplasia). Long-term ozone exposure did not appear to alter susceptibility to 1-NN injury in other nasal regions. This study shows that long-term ozone exposure has a protective effect on the susceptibility of nasal transitional epithelium to subsequent 1-NN, a result that clearly contrasts with the synergistic toxicological effect observed in pulmonary airway epithelium in response to the same exposure regimen.

Original languageEnglish (US)
Pages (from-to)300-309
Number of pages10
JournalAmerican Journal of Respiratory Cell and Molecular Biology
Volume38
Issue number3
DOIs
StatePublished - Mar 1 2008

Keywords

  • 1-nitronaphthalene
  • Goblet cell metaplasia
  • Nasal transitional epithelium
  • Ozone
  • Protein adduct formation

ASJC Scopus subject areas

  • Molecular Biology
  • Pulmonary and Respiratory Medicine
  • Clinical Biochemistry
  • Cell Biology

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