Rat lung metallothionein and heme oxygenase gene expression following ozone and zinc oxide exposure.
Cosma-G; Fulton-H; DeFeo-T; Gordon-T
Toxicol Appl Pharmacol 1992 Nov; 117(1):75-80
The induction of target genes in the lung following exposure to occupationally relevant levels of zinc-oxide (1314132) (ZnO) and ozone (10028156) was investigated in rats. Male Sprague-Dawley-rats were exposed nose only to ZnO for 3 hours at concentrations of 1.0, 2.5, or 5.0mg/m3, or to ozone at 0.5 or 1.0 part per million (ppm) concentrations. ZnO fumes were generated from a combustion furnace. The 3 hour exposure to ZnO fumes caused a substantial elevation in lung metallothionein (MT) mRNA at all concentrations tested. Exposures to 5 and 2.5mg/m3 ZnO caused an eight fold increase in MT mRNA levels with 8, 11, and five fold increases observed after the same ZnO exposure levels. Heme-oxygenase (HO) mRNA values returned to control levels 24 hours after exposure. No elevation was noted in gene expression following a 6 hour exposure to 0.5 and 1ppm ozone, even when lungs were examined as late as 72 hours after exposure. The authors conclude that the induction of target gene expression followed the inhalation of ZnO at concentrations equal to and below the current recommended threshold limit value of 5mg/m3 ZnO. The lack of effect of ozone exposure on MT and HO gene expression suggests no involvement of these genes in the acute respiratory response to this oxidant compound.
NIOSH-Publication; NIOSH-Grant; Pulmonary-system-disorders; Genotoxic-effects; Laboratory-animals; Inhalation-studies; Lung-cells; Pulmonary-function-tests; Toxic-gases; Metal-fume-fever; Respiratory-system-disorders
Occupational Medicine Yale Univ Sch of Med 333 Cedar St/cb 5039 New Haven, CT 06510
Toxicology and Applied Pharmacology
Yale University, New Haven, Connecticut