I am working on ischemic model of hDPSCs. I want to study apoptosis in the cells challenged for different periods of ischemia (3, 6, 12, 24, 48, and 72 h). I am following standard protocols of PI and AO/EtBr staining for the study however not getting the expected results. The bright field imaging showed toxicity in the cells but not in PI and AO/EtBr stained cells. Kindly give your valuable suggestions.