Figure 4.

MAPK/ERK pathway is involved in EF-mediated angiogenic response. (a) Treatment with MEK inhibitor U0126 resulted in decreased characteristic network size in all groups (n = 5, p < 0.05), and effectively abolished the increase in capillary morphogenesis in the high-frequency EF group, when compared with low-frequency EF and no-EF groups (n = 5, p < 0.001), suggesting that angiogenic effects of EF involve the MEK/ERK pathway. (b) Similarly, the VEGF release by endothelial cells in the presence of U0126 was significantly reduced in all groups, with VEGF levels significantly smaller in high-frequency EF than no-EF group (n = 4, p < 0.001).