ToxSci Advance Access published online on December 22, 2006
Toxicological Sciences, doi:10.1093/toxsci/kfl195
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Effect of Smoking Conditions and Methods of Collection on the Mutagenicity and Cytotoxicity of Cigarette Mainstream Smoke
* Labstat International Inc., Kitchener, ON, Canada N2C 1L3
Lauterbach & Associates, LLC, Macon, GA 31210-4708 USA
1 To whom correspondence should be addressed at Labstat International Inc., 262 Manitou Drive, Kitchener, Ontario Canada N2C 1L3. Tel: +519-748-5409. Fax: +519-748-1654. E-mail: wrickert{at}labstat.com.
Received August 17, 2006; accepted December 20, 2006
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Abstract |
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There is a history for the use of in vitro bioassays to assess the toxicological properties of mainstream cigarette smoke (MSS). The results described in the literature were, for the most part, obtained with MSS collected under FTC (or ISO conditions). However, numerous studies have shown that smokers smoke their cigarettes more intensely (e.g., they take larger puffs and/or more frequent puffs and/or partially occlude filter ventilation) than they are smoked on smoking machines operated under FTC (or ISO) conditions. It has also been reported that MSS composition changes with changes in smoking conditions. Furthermore, some governmental agencies have adopted regulations that specify more intensive protocols (i.e., Health Canada Intensive, HCI) for the collection of MSS for in vitro toxicological assays. Consequently, the performance of the Ames assay (TA98+S9, TA100+S9) and NRU assay under ISO and HCI protocols was studied with two blended (KR1R4F/KR2R4F, KR1R5F) and one flue-cured (CIM-7) reference cigarettes. The main outcome was when results were reported on a per milligram TPM basis, TPM (that portion of the mainstream smoke which is trapped in the smoke trap, expressed as milligrams per cigarette) generated under ISO conditions was more mutagenic and more cytotoxic than was TPM generated under HCI conditions. However, the decrease in biological activity could not be explained only by the increased in the water content of the TPM on going from ISO to HCI smoking conditions and the results may be influenced by differences in smoke chemistry as a result of differing smoke collection systems.
Key Words: Mutagenicity; Ames assay; Salmonella typhimurium TA98 / TA100; Cytotoxicity; Neutral red assay; TPM; Cigarette smoke gas-vapor phase; Kentucky reference cigarette; Canadian Industry Monitor cigarette.