TUNEL (terminal-deoxynucleotidyl transferase meditated nick
end labeling) is a common method for identifying apoptotic cells in
situ by detecting DNA fragmentation. When the genomic DNA is
broken, the exposed 30-OH at the end of deoxynucleotide transfer
as the catalytic plus green fluorescent probes fluorescein (FITC)
labeled dUTP, which can be detected by fluorescence microscopy or
flow cytometry, as indicated by a green color (in the web version).
The results were illustrated in Fig. 4.
For fluorescence microscopy, Fig. 4 revealed that A549 cells
treated with the compound 5f at different time appeared in green
(in the web version), indicating that compound 5f significantly
induced apoptosis against A549 cell line. The results were consistent
well with the previous experiments.