As shown in Fig. 3, significant increases in malondialdehyde (MDA) level and protein kinase C alpha (PKC-α) expression along with an apparent decrease in superoxide dismutase (SOD) expression were observed in the renal cortical tissues of diabetic rats compared with that of the control rats (p < 0.05) reflecting an increase in oxidative stress in diabetes. Here, SOD1 is linked to diabetes mellitus.