Figure 8

Analysis of apoptosis by TUNEL staining in human fibroblasts (n = 6) compared to control cells (n = 5) (×20). Counter staining was performed using DAPI nuclear staining and pictures were taken using DAPI (upper row), FITC (fluorescein isothiocyanate; middle row) and Merged (lower row) filters. Results are shown for a positive and negative control (A, B), healthy control fibroblasts (C), PXE fibroblasts (D) and PXE fibroblasts transfected with RUNX2 siRNA respectively 24 (E), 48 (F) and 72 hours (G) following transfection. PXE fibroblasts show smaller nuclei on the DAPI stain and increased TUNEL staining in the cytoplasm of fibroblasts compared to controls, reflecting a three-fold increase of apoptosis (2,08% vs 0.69% respectively, p < 0.05). Twenty-four and 48 hours post-transfection with RUNX2 siRNA, a decrease of apoptosis can be seen, whereas after 72 hours no difference can be observed compared to untreated PXE fibroblasts. Scale bar = 20 μm.