Fig. 4. Down regulation of PECAM-1 using siRNA. The expression of PECAM-1 was assessed by (A) immunofluorescence (PECAM-1=green; TOPRO-3=blue) and (B) western blotting using specific antibodies. Primary cultures of human endothelial cells were either left untreated (a, CTL) or treated with either (b) liposomal transfection agent, (c) scrambled oligonucleotides (Scr) or (d) PECAM-1 siRNA (siRNA) oligonucleotides for 48 hours. The bar graph summarizes the results of six independent experiments; ^***P<0.001 versus CTL.