Collagen mRNA content and distribution in the lungs of rats exposed to ozone.
Armstrong-LC; Watkins-K; Pinkerton-KE; Last-JA
Am J Respir Cell Mol Biol 1994 Jul; 11(1):25-34
The effect of ozone (10028156) on collagen messenger RNA (mRNA) content and distribution was assessed in rat lung. Adult Sprague-Dawley-rats were exposed to either filtered air or 1.2 parts per million ozone for 7 days; rats were killed within 1 hour of the end of the exposure period for determination of mRNA content as well as collagen and total protein synthesis rates. The alpha1(I) procollagen mRNA concentration was significantly increased in the lungs of rats exposed to ozone in comparison to controls; the concentrations of the mRNAs for alpha1(III) procollagen and for beta-actin, however, were not significantly changed. The synthesis of type-I collagen in the lungs of rats exposed to ozone was 142% greater than in controls; synthesis of type-III collagen, in contrast, apparently increased by only 24%. Sites of increased expression of the alpha1(I) procollagen mRNA were localized via in-situ hybridization of paraffin embedded tissue sections; increased amounts of alpha1(I) procollagen mRNA were detected in the septal tips and peribronchiolar regions of ozone exposed animals. In addition, an apparent diffuse increase in alpha1(III) procollagen mRNA expression was observed. The authors conclude that exposure of rats to high concentrations of ozone causes an increase in the lung content of mRNA for type-I collagen.
Laboratory-animals; Lung-cells; Genotoxic-effects; Toxic-gases; Cell-damage; Pulmonary-system; Protein-synthesis; Lung-fibrosis; Pollutants
Jerold A. Last, Ph.D., California Regional Primate Research Center, University of California, Davis, CA 95616-8542
American Journal of Respiratory Cell and Molecular Biology
University of California - Davis