CYTOTOXICITY ASSESSMENT OF WHOLE SMOKE AND VAPOR PHASE OF MAINSTREAM AND SIDESTREAM CIGARETTE SMOKE FROM THREE KENTUCKY REFERENCE CIGARETTES

Assessment of the cytotoxicity of mainstream and sidestream cigarette smoke has traditionally involved exposure of cell cultures to the particulate matter of smoke. For a more complete assessment of cigarette smoke cytotoxicity, a technique (cellular smoke exposure technique or CSET) was developed to directly expose mammalian cell cultures to either whole mainstream or sidestream cigarette smoke. The objective of this study was to compare the cytotoxicity of whole smoke or vapor phase from mainstream or sidestream smoke of three Kentucky reference cigarettes. The cigarettes compared were a high "tar" cigarette (2R1), a low "tar" cigarette (1R4F), and an ultra low "tar" cigarette (1R5F). Cytotoxicity was assessed in two cell types (WB rat liver cells and CHO cells) using the neutral red cytotoxicity assay. The order of cytotoxicity of mainstream smoke from the three cigarettes expressed on a per cigarette basis was 2R1 > 1R4F > 1R5F: Sidestream smoke from all three reference cigarettes was more toxic than the respective mainstream smoke on a per cigarette basis. The vapor phase of mainstream or sidestream smoke was the major contributor to the cytotoxicity of the whole cigarette smoke. Finally, the comparative trends in cytotoxicity between the smoke from the three reference cigarettes was similar in the two cell types, but CHO cells were more sensitive. CSET is a useful system to assess the cytotoxicity of cigarette smoke and may serve as an appropriate adjunct to the use of isolated particulate matter for the in vitro toxicological assessment of cigarette smoke and other aerosols.