SOD1 and diabetes mellitus: In particular, the levels of catalase (CAT) (as shown in Figure 3A), superoxide dismutase (SOD) (as shown in Figure 3B), and glutathione peroxidase (GPx) (as shown in Figure 3C) were significantly reduced in the diabetes group (p < 0.01), which is indicative of enzyme depletion that is generated by oxidative stress.