2.6. Endothelial cells permeability assay

Measurement of transendothelial electrical resistance (TER) and FITC‐Dextran transendothelial flux was performed to evaluate endothelial permeability. As us published previously,12 for TER measurement, HUVECs were incubated on the upper chamber of 0.4 μm‐pore‐size‐transwell (US，Coming Costar) to 100% confluence and stimulated with 100 μg/mL AGEs for corresponding time, then EVOM² (World Precision Instruments, USA) was used to measure monolayer permeability. To test transendothelial flux of FITC‐Dextran, cells were seeded on the upper chamber and incubated with FITC‐labelled dextran (1 mg/mL) for 45 min, then immediately collected 200 μL supernatant in the upper and bottom chamber, respectively, and determined the concentration of FITC‐dextran using HTS 7000 microplate reader. The permeability coefficient of dextran was calculated as follows: Pd = [A]/t × 1/A × V/[L], with [A] indicates the concentration of bottom chamber, [L] represents the upper ones, t represents time in seconds, A refers to the membrane area (in cm²), and V indicates the volume of the bottom chamber.