Optimisation of cell-based assays for medium throughput screening of oxidative stress.

Identification and development of cell-based assays adapted to medium throughput screening requirements is important when screening chemicals for their potential toxic properties. We describe here rapid fluorometer-based and spectrophotometer-based microplate assays which allow for the evaluation of oxidative stress in hepatocyte cell cultures by measurement of three markers: production of hydroperoxide assessed by the DCFH-DA probe, cellular antioxidant status by measurement of reduced glutathione and glutathione peroxidase activity and cytotoxicity and mitochondrial damage by evaluation of the mitochondrial transmembrane potential with rhodamine 123 fluorescent dye. The assays described here are rapid, simple and inexpensive, which are desirable when setting up screening assays. This system should be useful in selecting candidate compounds during the pre-development phase of agrochemicals or pharmaceuticals. It should also be of interest for retrospective and explanatory studies of mechanisms underlying toxicity observed in vivo.