4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a potent pulmonary carcinogen found in unburned tobacco and tobacco smoke. To exert its carcinogenic effect, NNK is metabolically activated to reactive intermediates that can damage DNA by alkylation or pyridyloxobutylation. NNK also has the ability to induce DNA oxidation and alter DNA repair activities that can result in deficient repair and potentially exacerbate carcinogenesis. Base excision repair (BER) is a ubiquitous DNA repair system that mainly repairs oxidative DNA damage. The goal of this study was to determine the effect of NNK on DNA oxidation status and BER activity in A/J mouse lung and liver. Female mice were treated with 10 µmol of NNK i.p. and lung and liver were isolated 1, 2 and 24 hours post administration. DNA was isolated from lung and liver, and the formation of 8-hydroxydeoxyguanosine (8-OHdG, a biomarker of DNA oxidation) was assessed by high-performance liquid chromatography with electrochemical detection. At 1, 2 and 24 hours in both murine lung and liver, there was no statistically significant difference in 8-OHdG levels (n = 4, P > 0.05) between control and NNK-treated mice. To assess BER, cell-free whole tissue nuclear protein extracts from liver and lung were prepared and incubated with a plasmid substrate containing oxidative DNA damage. In vivo treatment with NNK did not alter BER activity in lung or liver compared to control mice (n=3 or 4, P > 0.05). These experiments indicate that acute treatment with a tumourigenic dose of NNK does not significantly stimulate oxidative DNA damage or significantly alter BER activity in murine lung and liver. / Thesis (Master, Pharmacology & Toxicology) -- Queen's University, 2011-04-28 17:42:08.172
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OKQ.1974/6465 |
| Date | 29 April 2011 |
| Creators | Gupta, Neeraj |
| Contributors | Queen's University (Kingston, Ont.). Theses (Queen's University (Kingston, Ont.)) |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Rights | This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner. |
| Relation | Canadian theses |
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