Flow cytometry measurements were performed using a
Cytomics FC 500 flow cytometer (Beckman Coulter) equipped with
a 488 and 633 nm excitation light source from an argon ion laser.
Green fluorescence from samples (corresponding to DiBAC4(3) and
cFDA-stained cells) was collected on the FL1 channel (530 nm),
whereas PI fluorescence was registered on the FL3 channel
(610 nm). Each analysis was performed in duplicate at a low flow
rate setting (4000 events/s). Data acquisition was carried out using
Cytomics RXP software (Beckman Coulter). Gates and quadrants
were established according to staining controls. For DiBAC4(3)/PI
and cFDA/PI dual-parameter flow cytometric analysis, data respectively
collected from 150,000 and 100,000 events were analyzed
using Summit v4.3 software (DakoCytomation, Colorado, USA).