Effect of EphB4/EphrinB2 Reverse Signal on Angiogenesis Induced by Xuefu Zhuyu Capsule（血府逐瘀胶囊） Containing Serum in Human Microvascular Endothelial Cell 1

Objective： To evaluate the effect of Xuefu Zhuyu Capsule（血府逐瘀胶囊）-containing serum（XFZY-CS） on Eph B4/ephrin B2 and its reverse signal in human microvascular endothelial cell-1（HMEC-1）. Methods： XFZY-CS and the blank control serum were collected. HMEC-1 cells were randomly assigned to 6 groups including the concentration 1.25%, 2.5%, and 5% XFZY-CS groups and their blank serum control ones. The angiogenesis effect of XFZY-CS was tested with an in vitro tube formation assay and the best condition of pro-angiogenesis was determined. The effect of XFZY-CS on Eph B4/ephrin B2 and the reverse signal were determined by Western blot and real-time quantitative polymerase chain reaction, respectively; we also confirmed the results through activating and inhibiting the reverse signal by Eph B4/fc and pyrophosphatase/phosphodiesterase2（PP2）. Results： XFZY-CS promoted angiogenesis at the concentration of 2.5% corresponding serum after being cultured for 48 h, while inhibited angiogenesis at the concentration of 5% after culturing for 48 and 72 h. Under the 2.5% serum concentration, XFZY up-regulated the expression of Eph B4-m RNA at 12 h（P〈0.05）, and down-regulates its expression at 24 h（P〈0.01）. Protein expression of Eph B4 was apparently up-regulated at 12 h and down-regulated at 24 h. The phosphorylation of ephrin B2 increased at 9 h（P〈0.05）. In addition, 2.5% XFZY-CS played a similar role as the reverse signaling activator Eph B4/Fc ranging from 0.5 to 5 μg/m L（P〉0.05）. XFZY-CS also reduced the inhibitive effect of PP2 in limited periods. Conclusion： Eph B4/ephrin B2 was the upstream signal in the process of angiogenesis and its reverse signaling was responsible for XFZY＇s effect on promoting angiogenesis.