title: Inhalation of benzene leads to an increase in the mutant frequencies of a lacI transgene in lung and spleen tissues of mice.
abstract: The goal of this study was to determine if inhalation of benzene leads to an increase in the mutant frequencies in the tissues of male C57BL/6 mice. Mutant frequencies were measured using a previously described assay in which bacteriophage lambda lacI transgenes are rescued from mouse genomic DNA as infectious phage and scored for their LacI phenotype. Eight experimental mice were exposed to a target concentration of 300 ppm of benzene for 6 h/day x 5 days/week x 12 weeks, and eight control mice were treated similarly except that they were not exposed to benzene. Mutant frequencies were calculated as the ratio of LacI-/total phage recovered from organs of interest. The mean mutant frequency measured in lung tissues of mice exposed to benzene was (10.6 +/- 1.4) x 10(-5), which is about 1.7-fold higher than that of the unexposed controls. In spleen tissues from benzene-exposed mice the mean mutation frequency was (12.6 +/- 4.1) x 10(-5), which is about 1.5-fold higher than that of spleen tissues from unexposed controls. The differences in mean mutant frequencies between benzene-exposed and unexposed lung and spleen tissues are statistically significant. In liver tissues, however, the mean mutant frequencies of benzene-exposed mice and unexposed mice are not significantly different. These results demonstrate that inhaled benzene results in a statistically significant increase in the mutant frequencies in lung and spleen, but not in liver tissues of mice.
authors.affiliation: Department of Cell and Molecular Biology, Tulane University, New Orleans, LA 70118-5698.
authors.forename: A H
authors.initials: AH
authors.lastname: Mullin
authors.forename: R
authors.initials: R
authors.lastname: Rando
authors.forename: F
authors.initials: F
authors.lastname: Esmundo
authors.forename: D A
authors.initials: DA
authors.lastname: Mullin
mesh_terms: D000280:Administration, Inhalation; D000818:Animals; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics*; D010582:Bacteriophage lambda / Q000187:drug effects / Q000235:genetics; D001554:Benzene / Q000008:administration & dosage / Q000633:toxicity*; D004274:DNA, Recombinant / Q000235:genetics / Q000302:isolation & purification; D004790:Enzyme Induction; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter / Q000187:drug effects*; D005813:Genes, Synthetic / Q000187:drug effects*; D005822:Genetic Vectors / Q000187:drug effects / Q000235:genetics; D056968:Lac Repressors; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008168:Lung / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009152:Mutagenicity Tests; D009928:Organ Specificity; D011993:Recombinant Fusion Proteins / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics*; D013154:Spleen / Q000187:drug effects* / Q000378:metabolism; D001616:beta-Galactosidase / Q000096:biosynthesis
chemical_list: D001426:Bacterial Proteins; D004274:DNA, Recombinant; D029968:Escherichia coli Proteins; D056968:Lac Repressors; C539064:LacI protein, E coli; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D001616:beta-Galactosidase; D001554:Benzene