Apoptotic Cell Determination by DNA Fragmentation Assay

K562 cells (5×10⁴ cells) treated with the 25, 50, 100 µmol/L emodin for 48 hours were suspended in 100 µL of 10 mM Tris-HCl and 10 mM ethylenediaminetetraacetic acid (EDTA; pH 8.0). The cells were then treated with 100 mL of a solution that contained 10 mM Tris-HCl, 10 mM EDTA (pH 8.0), 2% sodium dodecyl sulfate (SDS), and 20 mg/mL proteinase K. The mixture was then incubated at 37°C followed by DNA extraction with phenol/chloroform. DNA fragmentation analysis was done with 10 mg DNA prepared from control cells, and cells were treatedwith 25, 50, 100 µmol/L emodin for 48 hours.DNA laddering was analyzed using 2% agarose gel electrophoresis and ethidium bromide staining.