Quantifying TUNEL-positive Cells in CMVECs

CMVECs were previously seeded on poly-l-lysine-treated coverslips. Fixed cells were stained using a terminal deoxynucleotidyl transferase-mediated dUTPbiotin nick end labeling (TUNEL) kit according to the manufacturer's instructions (Click-iT Plus TUNEL Kit, Thermo Fisher), and cell nuclei were stained with DAPI, as previously reported [18 (link)]. For quantification, the TUNEL-positive cells were counted in at least five randomly chosen visual fields in three independent samples under a fluorescence microscope (Olympus). The total number of cells was counted using DAPI staining, and the average ratio of TUNEL-positive cells was calculated.