Tacrine-induced reactive oxygen species in a human liver cell line: The role of anethole dithiolethione as a scavenger

The mechanisms leading to tacrine (THA) hepatotoxic effects are not yet ful ly understood. Reactive oxygen species (ROS) overproduction and intracellul ar reduced glutathione (GSH) depletion are common mechanisms involved in dr ug toxicity. The aim of this study was to investigate, on the human liver c ell line HepG2. whether THA at human blood concentrations induces ROS produ ction stimulation and/or GSH depletion. A possible effect of a free radical scavenger, anethole dithiolethione (ADT), was also assessed. ROS productio n was measured with a fluorogen probe 2',7'-dichlorofluorescin diacetate (D CFH-DA). Reduced GSH and cell viability were measured with, respectively, m onochlorobimane (mBCl) and neutral red probes. Assays were performed direct ly on living adherent cells in 96-well microplates, and sensitive fluoresce nt detection used microplate cytofluorimetry with cold light fluorimetry te chnology. The results showed that THA induced a concentration-dependent inc rease in ROS production and a decrease in GSH. Furthermore, for THA concent rations between 10 and 100 mu M ADT protected cells from ROS production sti mulation and GSH depletion induced by THA. In conclusion, our ill vitro stu dy demonstrates that oxidative stress. evidenced by enhanced ROS production and GSH depletion, is a mechanism involved in THA cytotoxicity. Moreover, ADT is effective in preventing THA-induced injury. (C) 1999 Published by El sevier Science Ltd. All rights reserved.