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Fig. 1
Figure 1. Acute and chronic VEGF exposures induce distinct pattern of signaling cascade activation (A and B) HUVECs were cultured in low-serum EMB for 4 h and then exposed to single stimulus of VEGF (10 ng/mL) and three stimuli of VEGF (10 ng/mL) with 30-min intervals, respectively. Cell lysates were collected 10 min after VEGF stimulation and subjected to western blotting (A). Band intensities were analyzed and compared (N = 5 for each group) (B). (C) HUVECs were labeled with DAF-FM (2.5 μM) and then exposed to acute and chronic VEGF stimulation, respectively. DAF-FM fluorescence was measured at Excitation/Emission of 495/515 nm and expressed as relative folds of control group. Data is representative of 3 independent experiments and expressed as mean ± SD. ∗, p<0.05, ∗∗, p<0.01, ∗∗∗, p<0.001.