SOD2 and Hyperglycemia: The obtained data demonstrated that hyperglycemia increases trimethyl histone H4 lysine 20 (H4K20me3), acetyl histone H3 lysine 9 (H3K9), and NF-κB p65 at the promoter and enhancer of retinal SOD2, resulting in gene-activating epigenetic changes in MnSOD and decreased expression of SOD2.