Knockdown of ephrinB2 with siRNA and its effects on in vitro tubular formation. (A) Knockdown of ephrinB2 in HUVECs was evaluated both at mRNA and protein levels. The reduction rates in fold expression (ephrinB2 siRNA/control siRNA) of mRNA and protein levels were approximately 27% and 60%, respectively. (B) Effect of ephrinB2 knockdown on HUVEC tubular formation. Representative microphotographs at ×100 magnification from triplicate wells of 2 repeated experiments are shown. Quantitative data of cord length (C) and branch point number (D). Data are shown as mean plus or minus SE of triplicate wells in 2 experiments. *P < .05 versus control siRNA without VEGF and §P < .05 versus control siRNA with VEGF by 1-way ANOVA with Fisher least-significant-difference test.