Similarly, quantification by each retinal layer demonstrated minimal GFAP expression in CTL and DM followed by significant elevation in DR in the INL (CTL: 100.0 ± 15.0%, DM: 188.3 ± 85.3%, DR: 5731.9 ± 2270.5%; CTL vs. DR: p ≤ 0.001; DM vs. DR: p ≤ 0.001), OPL (CTL: 100.0 ± 22.1%, DM: 37.8 ± 25.5%, DR: 11456.0 ± 2905.7%; CTL vs. DR: p ≤ 0.0001; DM vs. DR: p ≤ 0.0001) and ONL (CTL: 100 ± 49.1%, DM: 99.0 ± 50.4%, DR: 7720.5 ± 1685.1%; CTL vs. DR: p ≤ 0.0001; DM vs. DR: p ≤ 0.0001). This evidence concerns the gene GFAP and diabetes mellitus.