RESEARCH POSTER PRESENTATION DESIGN © 2011 www.PosterPresentations.com

The purpose of this study was to evaluate the impact of several factors on smoke cytotoxicity measurements in an in vitro whole smoke exposure system. Effects of incubation time after smoke exposure, cell types used, and smoke regimens on the cytotoxicity of cigarette smoke were investigated. Mainstream cigarette smoke was generated from the 3R4F reference cigarettes using a VC10 smoking robot under the ISO regimen (35/60/2 without blocking of filter ventilation) or the HCI regimen (55/30/2 with complete blocking of filter ventilation). Cells were exposed to fresh whole smoke (WS) in the VITROCELL ® system, and cytotoxicity was evaluated using the neutral red uptake (NRU) assay. Results showed 24 hrs after smoke exposure appeared to be an optimal time-point to assess smoke cytotoxicity. CHO cells were more sensitive to smoke-induced cytotoxic effects than A549 cells. Smoke regimen evaluation was conducted in both cigarette smoke condensate (CSC) and WS. For CSC testing, the cytotoxicity decreased going from the ISO regimen to HCI regimen on a per unit of total particulate matter (TPM) basis. For WS exposure testing, cytotoxicity under the ISO regimen was less than that under the HCI regimen when smoke doses were expressed as % of cigarette smoke; notably, when smoke doses were converted to TPM (µg), cytotoxicity under the HCI regimen was less than that under the ISO regimen. A clear dose-response relationship between cell viability and smoke doses was observed under all test conditions. These data indicated that this in vitro smoke exposure system can be a useful tool to study the toxicological effects of WS, and the test conditions can have an important impact on the results of cytotoxicity evaluation of cigarette smoke. With the advance of in vitro whole smoke (WS) exposure technology, more studies now evaluate the fresh WS for toxicological responses (Aufderheide and Gressmann, 2008; Okuwa et al., 2010). WS might reflect completely the biological effects of native smoke. Cytotoxicity assays are part of a battery of in vitro assays for assessing the potential toxicity of tobacco products. Here we evaluated the impact of test conditions on smoke cytotoxicity measurements in an in vitro whole smoke exposure system