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 sm oke has traditionally involved exposure of cell cultures to the particulate m atter of smoke. For a m ore com plete assessment of cigarette sm oke cytotoxicity, a technique (cellular smoke exposure technique or CSET) was developed to directly expose mammalian cell cultures to either whole mainstream or sidestream cigarette sm oke. The objective of this study was to com pare the cytotoxicity of whole smoke or vapor phase from mainstream or sidestream sm oke of three Kentucky reference cigarettes. The cigarettes com pared 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 m ainstream smoke from the three cigarettes expressed on a per cigarette basis was 2R1 > 1R4F > 1R5F. Sidestream sm oke 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 com parative 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 m ay serve as an appropriate adjunct to the use of isolated particulate matter for the in vitro toxicological assessment of cigarette smoke and other aerosols.