Walnut Oligopeptide Delayed Improved Aging-Related Learning and Memory Impairment in SAMP8 Mice

Abstract

Aging-related learning and memory decline are hallmarks of aging and pose a significant health burden. The effects of walnut oligopeptides (WOPs) on learning and memory were evaluated in this study. Sixty SAMP8 mice were randomly divided into four groups (15 mice/group), including one SAMP8 age-control group and three WOP-treated groups. SAMR1 mice (n = 15) that show a normal senescence rate were used as controls. The SAMP8 and SAMR1 controls were administered ordinary sterilized water, while the WOP-intervention groups were administered 110, 220, and 440 mg/kg·bw of WOPs in water, respectively. The whole intervention period was six months. The remaining 15 SAMP8 (4-month-old) mice were used as the young control group. The results showed that WOPs significantly improved the decline in aging-related learning/memory ability. WOPs significantly increased the expression of BDNF and PSD95 and decreased the level of APP and Aβ1-42 in the brain. The mechanism of action may be related to an increase in the activity of antioxidant enzymes (SOD and GSH-Px), a reduction in the expression of inflammatory factors (TNF-α and IL-1β) in the brain and a reduction in oxidative stress injury (MDA). Furthermore, the expression of AMPK, SIRT-1, and PGC-1α was upregulated and the mitochondrial DNA content was increased in brain. These results indicated that WOPs improved aging-related learning and memory impairment. WOP supplementation may be a potential and effective method for the elderly.

The Protective Effect of Walnut Oligopeptides against Indomethacin-Induced Gastric Ulcer in Rats

“…Walnut oligopeptides (WOPs), which have characteristics such as a low molecular weight, high absorption, bioavailability, and safety, are extracted from walnut protein by using biological enzyme hydrolysis technology. Studies have found that WOPs have numerous potential physiological functions, including anti-fatigue [ 14 ], improved anti-oxidation capacity [ 15 ], improved aging-related learning and memory impairment [ 16 ], and the inhibition of cell apoptosis of spleen tissue induced by ionizing radiation in mice [ 17 ]. However, the effect of WOPs on NSAID-related gastric ulcers is rarely reported.…”