CYTOTOXICITY ASSESSMENT OF WHOLE SMOKE AND VAPOR-PHASE OF MAINSTREAM AND SIDESTREAM CIGARETTE-SMOKE FROM 3 KENTUCKY REFERENCE CIGARETTES

Assessment of the cytotoxicity of mainstream and sidestream cigarette smoke has traditionally involved exposure of cell cultures to the part iculate matter of smoke. For a more complete assessment of cigarette s moke cytotoxicity, a technique (cellular smoke exposure technique or C SET) was developed to directly expose mammalian cell cultures to eithe r whole mainstream or sidestream cigarette smoke. The objective of thi s study was to compare the cytotoxicity of whole smoke or vapor phase from mainstream or sidestream smoke of three Kentucky reference cigare ttes. The cigarettes compared were a high ''tar'' cigarette (2R1), a l ow ''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 cyto toxicity of mainstream smoke from the three cigarettes expressed on a per cigarette basis was 2R1 > 1R4F > 1R5F: Sidestream smoke from all t hree reference cigarettes was more toxic than the respective mainstrea m smoke on a per cigarette basis. The vapor phase of mainstream or sid estream smoke was the major contributor to the cytotoxicity of the who le cigarette smoke. Finally, the comparative trends in cytotoxicity be tween the smoke from the three reference cigarettes was similar in the two cell types, but CHO cells were more sensitive. CSET is a useful s ystem to assess the cytotoxicity of cigarette smoke and may serve as a n appropriate adjunct to the use of isolated particulate matter for th e in vitro toxicological assessment of cigarette smoke and other aeros ols.