Measurement of apoptosis by flow cytometry

Single cell suspensions were collected from different treatment groups, and the percentage of cells in apoptosis were observed with the Annexin/PI staining kit following the manufacturer’s instructions (Abcam, Cambridge, UK). The sample was kept on ice for further flow cytometric analysis. All cell types undergoing apoptosis were quantified by staining with the Annexin V-FITC and PI. By conjugating FITC to Annexin V, it was possible to identify and quantify apoptotic cells on a single-cell basis by flow cytometry. For this experiment, the CellQuest software was used to quantify and analyze cells with early apoptotic (FITC⁺PI⁻) and late apoptotic or necrotic cells (FITC⁺PI⁺).