Research Paper Volume 11, Issue 15 pp 5399—5411

Figure 2. Representative histograms obtained for the positive (with DNase I) and negative (without TdT) controls and strategy applied in the TUNEL/PI flow cytometry analysis. In the fluorescence histograms, markers (M1, M2, M3) are set to exclude necrotic sperm cells and calculate the percentage of TUNEL-positive sperm cells (with fragmented DNA) read from the M2 marker. FL3 – red fluorescence channel for PI-stained cells, FL1 – green fluorescence channel for FITC-streptavidin-biotin-dNTP-labelled cells, TdT – terminal deoxynucleotidyl transferase, PI – propidium iodide, TdT – terminal deoxynucleotidyl transferase, TUNEL – terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling.