Fig. 3.

Effect of glutathione peroxidase and selenium on apoptosis and cell cycle arrest produced by a 96-h continuous exposure to doxorubicin in parental and Gpx-1 knockout cardiac fibroblasts. Apoptosis was evaluated by TUNEL assay; cell cycle progression of cells initially in log-phase growth was determined by flow cytometry. TUNEL positive cells were assessed across the cell cycle and are shown as strand breaks measured on the y-axis quantitated as events on the z axis. In these studies, continuous exposure to nanomolar concentrations of doxorubicin leads to accumulation of cells at the G2/M interface. These data are representative of at least three separate experiments.