SUMMARYThe aim of this study was to compare the results obtained from two in vitro cytotoxicity assays that depend upon different mechanisms/modes of action. The Neutral Red Uptake (NRU) assay is based on endocytotic activity whereas the Water Soluble Tetrazolium Salts (WST-1) assay is based on mitochondrial dehydrogenase activity. Both were investigated in light of their wide use and documented validation. The total particulate matter (TPM) and gas vapor phase (GVP) of main stream smoke derived from Kentucky reference cigarettes 3R4F and 10 test cigarettes made of 100% flue-cured or 100% Burley tobacco were individually applied to the two assays using CHO-K1 cells. In addition, cigarette smoke constituents and known cytotoxic agents, documented to affect specific endpoints, were evaluated within both assays. Although the NRU assay was primarily more sensitive than the WST-1 assay, both assays provided comparable results in terms of the rank order for the cytotoxicity of cigarette smoke samples. In addressing the cytotoxicity of constituents in cigarette smoke, acrolein, hydroquinone and catechol gave clear dose-related decreases in cell viability (an end point common in both assays). Moreover, enzyme inhibitors of the mitochondrial respiratory chain and chemicals causing membrane disruption also showed similar responses regardless of the specific endpoint addressed within the cytotoxicity assay. In conclusion, results from the NRU and WST-1 assay are comparable therefore indicating results were independent of the different assay detection mechanisms/modes of action. [Beitr. Tabakforsch. Int. 26 (2014) 98-108]
Comparative Study of Cigarette Smoke Cytotoxicity Using Two In Vitro Assay Systems
