Cell Counting Kit 8 (CCK-8) Cell Proliferation Assay

When determining the optimal concentration of H₂O₂, RPE cells were plated in a 96-well plate at 1800 cells/well for 24 h, cultured with 0–500 μM H₂O₂ for 4 h, and then cultured in complete medium for another 44 h. Cells from each group were collected and plated in a 96-well plate at 300 cells/well. After 24 h, 10 μl CCK-8 (Dojindo, Japan) solution was added to each well and incubated for 3 h with 5% CO₂ at 37°C. The optical density was measured by a microplate reader (BioTek, United States) at 450 nm. The CCK-8 assay was performed continuously for 7 days.