To mimic the bioassay employed in our previous carcinogenicity and DNA adduct studies [5 (link), 25 (link), 27 (link), 28 (link)], eight week-old female B6C3F1/J mice (Jackson Laboratories, Bar Harbor, ME) were used in this study. Mice were quarantined for about 1 week before treatment. All mice were kept on a 12-hr light:12-hr dark cycle, maintained at 50% relative humidity and 21± 2°C, and were fed with AIN-93M diet (5% corn oil), and water ad libitum. The bioassay was carried out in accordance with the NIH Guide for the Care and Use of Laboratory Animals and was approved by Institutional Animal Care and Use Committee.
Mice received topical treatment of DBP (24 nmol, 3 times per week for 5 weeks) in the oral cavity and were euthanized 48 h after the last dose; this time point was selected based on our previous study showing maximum levels of DNA adducts [25 (link)]. Animals treated with dimethyl sulfoxide (DMSO) as the vehicle were used as control. At termination, mice were euthanized by CO2 asphyxiation; oral tissues were isolated from the same anatomic sites of mice treated with vehicle or DBP (soft tissues of the oral cavity, including the buccal mucosa and floor of the mouth as well as soft tissues attached to the hard palate) and pooled together for DNA extraction.
Mice received topical treatment of DBP (24 nmol, 3 times per week for 5 weeks) in the oral cavity and were euthanized 48 h after the last dose; this time point was selected based on our previous study showing maximum levels of DNA adducts [25 (link)]. Animals treated with dimethyl sulfoxide (DMSO) as the vehicle were used as control. At termination, mice were euthanized by CO2 asphyxiation; oral tissues were isolated from the same anatomic sites of mice treated with vehicle or DBP (soft tissues of the oral cavity, including the buccal mucosa and floor of the mouth as well as soft tissues attached to the hard palate) and pooled together for DNA extraction.
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