Differential inducibility of rat pulmonary CYP1A1 by cigarette smoke and wood smoke

Michael M. Iba, Jacqueline Fung, Le Chung, Jason Zhao, Bozena Winnik, Brian T. Buckley, Lung Chi Chen, Judith T. Zelikoff, Yu Ru Kou

    Research output: Contribution to journalArticlepeer-review

    9 Scopus citations

    Abstract

    Mainstream cigarette smoke (CS) and wood smoke (WS) were compared in terms of their pulmonary CYP1A1 inducibility. The inducibility was assessed in pulmonary microsomes from rats exposed to freshly generated CS or WS and in rat lung explants treated with extracts of CS or WS total particulate matter (TPM). Mutagenicity in Salmonella typhimurium TA98 and TA100, an effect established for CS and WS in previous studies, was also examined as a test of the biological activity of the smoke samples in the present study. Pulmonary microsomal CYP1A1 activity (as measured by ethoxyresorufin O-deethylase), was induced 4.4-fold and 8.3-fold following exposure of rats to smoke from a single cigarette and three cigarettes, respectively, relative to the activity in control rats. The induction was paralleled by elevated CYP1A1 mRNA level (by northern blot analysis). WS, in contrast to CS, induced neither pulmonary CYP1A1 activity nor mRNA in exposed rats. CYP1A1 protein (by western blot analysis) was induced in cultured rat lung explants by extracts of CS TPM or by a high concentration (496 nM) of benzo[a]pyrene (B[a]P) but not by extracts of WS TPM or a low concentration (0.110 nM) of B[a]P. The induction by high B[a]P concentration was inhibited by extracts of CS or WS TPM, with the inhibition by extracts of WS TPM (75%) being greater than that by extracts of CS TPM (31%). Extracts of CS TPM were as mutagenic as extracts of WS TPM to Salmonella typhimurium TA98 but were more mutagenic than extracts of WS TPM to Salmonella typhimurium TA100. The results show that CS and WS are mutagenic but that WS differs from CS in its inability to induce pulmonary CYP1A1.

    Original languageEnglish (US)
    Pages (from-to)1-11
    Number of pages11
    JournalMutation Research - Genetic Toxicology and Environmental Mutagenesis
    Volume606
    Issue number1-2
    DOIs
    StatePublished - Jul 14 2006

    All Science Journal Classification (ASJC) codes

    • Genetics
    • Health, Toxicology and Mutagenesis

    Keywords

    • CYP1A1
    • Cigarette smoke
    • Induction
    • Mutagenicity
    • Rat lung
    • Wood smoke

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