Quantifying Apoptosis by Flow Cytometry

The quantification of apoptosis was determined by flow cytometry using an annexin V-FITC/PI double staining kit (BD Pharmingen, San Diego, CA, USA), according to the manufacturer’s instruction. Briefly, cells were treated with the desired concentrations of coptisine, for 24 h, in the presence or absence of Z-VAD-FMK (Sigma-Aldrich Chemical Co.). The collected cells were re-suspended in binding buffer, and then stained with PI solution and FITC-conjugated annexin V, for 15 min, in dark, as previously described [47 (link)]. The fluorescence intensities were detected by flow cytometry (BD Biosciences, San Jose, CA, USA) at the Core-Facility Center for Tissue Regeneration, Dong-eui University (Busan, Repbulic of Korea).