Apoptosis induction. Apoptosis of HUVECs seeded on collagen IV (50 μg/mL) was evaluated after 24 hours of RGDS (500 μg/mL) treatment at 37°C. (A) The apoptosis was visualized by TUNEL staining and by nuclear fragmentation (Hoechst staining). Nuclei stained with Hoechst as well as TUNEL-positive nuclei were identified by means of a Zeiss Axioplan fluorescence microscope (original magnification, × 40). The images shown refer to representative experiments. (B) Apoptosis was expressed as a percent of fragmented Hoechst-positive nuclei versus total Hoechst-positive nuclei, and as a percent of TUNEL-positive nuclei versus total Hoechst-positive nuclei and was reported as fold increase versus control. Quantification performed with the 2 staining methods gave similar results. (*P < .05). Experiments were carried out in triplicate. (C) Apoptosis was quantified by FACS analysis according to the PI staining in sub-G1-phase cells. Three independent experiments were performed with similar results; one representative experiment is shown.
