Induction of oxidative stress in murine cell lines by 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX)

3-Chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), the potent bacterial mutagen produced during chlorination of drinking water, was tested for the induction of oxidative stress in two murine cell lines: NIH 3T3 (fibroblasts) and L929 (fibrosarcoma cells). Following 1 h MX treatment at concentrations between 100 and 1000uM, cellular stress conditions were monitored by measuring reactive oxygen species formation (ROS) and reduced glutathione levels (GSH). The kinetics of ROS formation and GSH depletion was investigated from 10 min to 1 h. MX caused detachment of cells at 1000uM in L929 cells and at 300uM in NIH 3T3 cells but the viability of the cells, measured by the trypan blue assay, decreased only by 20 and 7 per cent, respectively, in 1 h. MX increased ROS production in L929 cells in a dose-dependent manner, by 120 per cent at 500uM of MX in 1 h. The maximum ROS production was attained already in 10 min. In NIH 3T3 cells, the ROS production was slightly, but not statistically significantly stimulated at 200uM between 20 and 60 min. Concomitantly, MX decreased the intracellular content of GSH dose-dependently in both cell lines, by 48 per cent in L929 cells at 500uM of MX and 32 per cent in NIH 3T3 cells at 200uM of MX in one hour. The majority of this GSH depletion had occurred in 10 min. These findings indicate that MX induces oxidative stress in mammalian cells in vitro though the sensitivity of cells may differ for this effect.