Rat fibroblasts were seeded in a 12-well plate at 1×104 cells/mL and irradiated the following day. 23.1 µL of MR-(DEVD)2 solution was mixed with media and added. 1 hour later, 300 µL media was added and cells MR-DEVD data were photographed over 16 hours. Bright field images show increasing red intensity as caspase activity and apoptosis progressed.View a time-lapse movie of caspase-3/7 activation in cultured rat fibroblasts. Data courtesy of Dr. Martin Purschke, MA General Hospital.