NBAE could increase the activities of total antioxidant capacity (T-AOC), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT), and reduce the level of malondialdehyde (MDA) in the serum of rats with STZ-induced DN, showing significant antioxidant activity in vivo. The gene discussed is CAT; the disease is liver dysplastic nodule.