RT-PCR analysis of SelS gene expression after transfection of siRNA-SelS into HUVEC cells. A. RT-PCR analysis of SelS mRNA in cell lysates. B. The level of SelS mRNA expression presented as a ratio to GAPDH following densitometric analysis of the RT-PCR products. M: marker; Con: control group; SelS1, SelS2, SelS3: siRNA-SelS1, 2 and 3 plasmids, respectively. *P < 0.01 compared with the control group.