In vitro genotoxicity of ethanol and acetaldehyde in human lymphocytes andthe gastrointestinal tract mucosa cells

The influence of ethanol and acetaldehyde on DNA in human lymphocytes, gast ric mucosa (GM) and colonic mucosa (CM) was investigated by using the comet assay. All kinds of cells were exposed to ethanol and acetaldehyde in two regimens: the cells were incubated with either chemical and analysed or the y were exposed first to ethanol, washed and then exposed to acetaldehyde an d analysed. Lymphocytes were exposed to ethanol at final concentrations of 30 mM and acetaldehyde at 3 mM. GM cells were incubated with ethanol at I h i and acetaldehyde at 100 mM. CM cells were exposed to ethanol at 10 mM and acetaldehyde at 100 mM. In combined exposure, the cells were subsequently exposed to ethanol and acetaldehyde at all combination of the concentration s of the agents. Ethanol caused DNA strand breaks, which were repaired duri ng 4 hr, except when this agent was applied in GM cells at a concentration of I hi. A dose-dependent decrease in the tail moment of all types of aceta ldehyde-treated cells was observed. Similar results were obtained when a re cognized DNA crosslinking agent, formaldehyde,,vas used. These results sugg est that acetaldehyde may form crosslinks with DNA. These crosslinks were p oorly repaired. CM cells showed the highest sensitivity of all cell types t o ethanol than lymphocytes and GM cells. There sere no differences in the s ensitivity to acetaldehyde of all the cell types. Our results clearly indic ate that ethanol and acetaldehyde can contribute to cancers of the digestiv e tract. (C) 2000 Elsevier Science Ltd. AII rights reserved.