Shinkichi Ishikawa, Yuki Kanemaru, Hidenori Nara, Kazuo Erami, Yasufumi Nagata
Scientific Product Assessment Center, R&D Group, Japan Tobacco Inc., 6-2 Umegaoka, Aoba-ku, Yokohama, Kanagawa 227-8512, Japan
This article shows the successful exposition exposure of cigarette smoke on two different Ames bacteria strains by using the Vitrocell exposure system including the VC10 smoking robot. Conventional 1 mg tar commercial cigarettes (CC1), 1R5F reference cigarettes (University of Kentucky,Lexington, KY, USA), and 3R4F reference cigarettes (University of Kentucky) were compared with a prototype heated cigarette (HC).
The Ames assay is useful for evaluating the mutagenic potentials of chemicals, and it has been used to evaluate the mutagenic potential of cigarette smoke (CS). In vitro direct exposure systems have been developed to mimic CS exposure in the human respiratory tract, and the Ames assay has been used with such systems. Ames tests were performed using the Vitrocell®direct exposure system in this study. The mutagenic potentials of whole mainstream CS and gas/vapor phase fractions produced by conventional combustible cigarettes under two smoking regimens were compared. Salmonella Typhimurium TA98 and TA100 were used with and without metabolic activation, and the number of revertants induced by exposure to each CS was determined. The amount of smoke particles to which cells were exposed were also determined, and dose-response curves describing the relationships between exposure to smoke particles and the number of revertants induced were plotted. The slopes of linear regressions of the dose-responsecurves were determined, and the slope for each CS was used as a mutagenic activity index for that CS. A new heated cigarette was also tested and smoke from the heated cigarette had a lower mutagenic activity in TA98 and TA100 with metabolic activation than did the conventional CS. The results indicate that the direct exposure system and the Ames test can be used to determine the mutagenic potentials of CS produced by different cigarettes under different conditions (i.e., using different Salmonella Typhimurium strains with and without metabolic activation, and using different smoking conditions).