COMPARATIVE-STUDIES OF DNA ADDUCT FORMATION IN MICE FOLLOWING DERMAL APPLICATION OF SMOKE CONDENSATES FROM CIGARETTES THAT BURN OR PRIMARILY HEAT TOBACCO

A new cigarette (Eclipse) that primarily heats rather than burns tobac co has been developed. Since Eclipse primarily heats tobacco, the smok e chemistry is much simplified, consisting of 80% glycerol and water. With the simplified smoke chemistry, it would be expected that toxicol ogical activity would be reduced. Smoke and smoke condensate from Ecli pse have consistently yielded markedly reduced mutagenicity and cytoto xicity in in vitro tests when compared to smoke and smoke condensate f rom the 1R4F Kentucky reference cigarette, which is representative of typical low 'tar' cigarettes sold in the U.S. today. The objective of the present study was to evaluate the potential of mainstream cigarett e smoke condensate (CSC) of Eclipse to produce DNA adducts in lung, he art and skin tissue of dermally-exposed mice and to compare the result s with those obtained with CSC from the 1R4F Kentucky reference cigare tte. CSC from Eclipse or 1R4F cigarettes was applied dermally to SENCA R mice three times a week for 30 weeks. Amounts of CSC applied were 30 , 60 or 120 mg 'tar' per animal per week. Tissues were collected after 1, 4, 14 and 29 weeks of CSC application. DNA adducts were analyzed i n lung, heart and skin tissues using the P-32-postlabeling method with P-1 nuclease modification. Distinct time and dose-dependent diagonal radioactive zones (DRZ) were observed in the DNA from lung, heart and skin tissues of animals treated with 1R4F CSC. The relative adduct lab eling (RAL) values of lung, heart and skin DNA from reference CSC-trea ted animals were significantly greater (p < 0.05) than those of the so lvent control animals. No corresponding DRZs were observed at any dose from the DNA of animals treated with CSC from Eclipse or solvent cont rol (acetone) and the RAL values observed following application of Ecl ipse were not increased relative to the solvent control. These results provide additional evidence that the smoke condensate from the Eclips e cigarette is markedly less genotoxic than smoke condensate from toba cco-burning cigarettes representative of those currently sold in the U .S. (C) 1998 Elsevier Science B.V. All rights reserved.