Fig. 2

DNA methylation investigation of the aberrant DNA methylation profile in DN. A The circos-plot shows the overall methylation status in the whole genome; B Comparison of CpG methylation levels among different groups, including healthy control (Group A), STZ (Group B), HM + STZ (Group C), and TSF (Group D); C The volcano plot shows up-regulated and down-regulated differentially methylated genes, where the blue area stands for hypo-methylation and the red area indicates hyper-methylation; D The heat map illustrates the top 60 differentially methylated genes between HM + STZ group and STZ Group. The color intensity states the degree of difference in methylated genes, where darker colors represent more pronounced differences. The blue color indicates an overall status of hypo-methylation, and the red color suggests hyper-methylation