Fig. (4) Reductide signal in living cells can be measured in a plate reader.BJ fibroblasts in a 96-well plate were pretreated with NAC (A) or CDNB (B) for 30 minutes. Cells were washed twice with PBS followed by incubation with reductide 1 µM for one hour. Wells were assayed for FAM fluorescence. TAMRA fluorescence was also assayed but was constant for all wells tested, i.e. not dependent on dose of redox modifying agent used in pretreatment (data not shown). BJ fibroblasts were treated with various concentrations of H₂O₂ in cell media for (C) four hours or (D) 24 hours. Following treatment, cells were washed with PBS and incubated with reductide 1 µM in cell media for four hours. In parallel, H₂O₂M treated fibroblasts were also assayed with Alamar Blue (cell viability assay) diluted 1:10 in cell media according to the kit manufacturer’s instructions.