2.3 CCK-8 assays
CCK-8 assays were used to select the appropriate concentration of harmine to use in subsequent experiments. First, 100μl of endothelial cell suspension was inoculated into a 96-well plate (5000 cells/well), incubated at 37℃ in a 5% CO2 saturation humidity incubator for 48h; we then aspirated the culture medium. The cells were then treated with different final concentrations of harmine prepared with fresh medium for 48h (0, 1, 3, 6, 16, 32, 64, 128 μmol/L); 3-4 multiple wells were created for each group. A blank group (an equal volume of medium without cells), a control group (an equal volume of medium with cells but without harmine treatment). We then added 10μl/well of CCK-8, incubated at 37℃ for 4h, and the OD value was measured at 450nm using a microplate reader.