Annexin 5 fluorescein isothiocyanate fitc propidium lodide pi apoptosis kit

The apoptosis and cell cycle distribution were assessed by flow cytometry assay. For the assessment of apoptosis, the Annexin V-Fluorescein isothiocyanate (FITC)/Propidium lodide (PI) Apoptosis Kit (BD Biosciences, San Jose, CA, USA) was used. Briefly, the transfected cells treated with a 4 Gy dose of IR were collected and washed with PBS (Sigma-Aldrich) for three times. Then, cells were incubated with a 200 µL binding buffer containing 10 µL Annexin V-FITC and 5 µL PI (Sigma-Aldrich). The FACS Canto™ II flow cytometer (BD Biosciences) was used to analyze the data of apoptosis. For the determination of cell cycle distribution, the transfected cells treated with 4 Gy dose of IR were harvested and washed by PBS (Sigma-Aldrich) for three times. Then, cells were incubated with PI at 37°C for 30 min. The distribution of G1, S, and G2/M phases in cells were inspected by BD FACS Canto™ II flow cytometer (BD Biosciences).