PPARA and Cognitive impairment: AUR and NGI did not significantly affect the protein expression of PPARγ in the hippocampus in this experiment (Figure 4); on the other hand, a previous study reported that NGI ameliorated cognitive deficits via oxidative stress and proinflammatory factor suppression, and activated the protein expression of PPAR in the hippocampus of an STZ-injected rat model [25].