Long-Term Walnut Oligopeptides Prevents Memory Loss in Aged SAMP8 Mice by Decreasing Oxidative Stress and Down-rRgulating the PI3K/Akt Signaling Pathway in Hippocampus

Abstract

Abstract Objectives Walnut Oligopeptides (WOPs), the effective component of walnut, has been reported to have a neuron protective effect, but the preventive effect on Alzheimer's disease (AD) related memory loss and the underlying mechanisms have not been well determined. Methods The senescence-accelerated mouse (SAM) is a useful model of AD-related memory impairment. In the present study, SAMP8 mice aged 4 months were chronically treated with ginsenoside (3 dose groups were given WOPs in diet for 6 months). The three groups were treated with WOPs 110, 220 and 440 mg/kg · bw per day, respectively. Placebo-treated aged mice and young ones (4 months old) were used as controls. In addition, SAMR1 mice were used as “normal aging” control. Results The beneficial role of WOPs was manifested in the prevention of memory loss in aged SAMP8 mice. The optimal dose of WOPs is 220 or 440 mg/kg per day. WOPs as found to significantly improve the memory ability of AD rats and anti-oxidase level significantly increased in serum. WOPs also reduced the content of Aβ and p-tau and improved the expression of PI3K and p-Akt/Akt in the hippocampus. Conclusions In conclusion, WOPs could improve the memory ability and reduce the content of Aβ and p-tau in SAMP8. The beneficial effects of WOPs were in part mediated by PI3K/Akt signaling pathway activation. Funding Sources This research was funded by the Bioactive Peptide Innovation Platform in Jilin province.