2.10. Transwell Migration Assay

The migration efficiency of LECs was assessed using 8 mm pore Transwell filter membrane (Corning) following reported method [20]. Briefly, the LECs were seeded at a density of 2 × 10⁵ cells/mL in the upper chamber, and in the lower chamber 100 ng/mL of SDF-1 was added. After incubation for 16 h, the cells on two sides of the membrane were dried in air and then fixed with 4% paraformaldehyde for 15 min. Subsequently, the cells were stained with DAPI for 10 min. The cells that migrated to the lower sides of the membrane were quantified by counting in 5 fields under a Nikon TE2000 inverted fluorescence microscope [21]. The same protocol was also performed in the presences of VEGF-C (60 ng/mL) or SDF-1 (100 ng/mL) + VEGF-C (60 ng/mL).