Confluent HUVEC monolayers were mechanically wounded
with a pipette tip and washed with phosphate-buffered saline
(PBS) to remove the debris. The wounded monolayers were
cultured in the complete EC medium (M199 supplemented
with 20 % FBS, 20 mmol/L HEPES (pH 7.4), 1 ng/mL
recombinant human fibroblast growth factor, 90 mg/mL
heparin and antibiotics). Wound closure was observed under
inverted microscopy, and the images were taken at different
time points. Wound closure was measured using softwares
and presented as relative distance in pixel (ImageJ) or distance
in lM (Leica microscopy imaging software) [17].