Long-Term Effect of Porcine Brain Enzyme Hydrolysate Intake on Scopolamine-Induced Memory Impairment in Rats

• Published in: International journal of molecular sciences 2022-03, Vol.23 (6), p.3361
• Main Authors: Zhang, Ting, Kim, Min Jung, Kim, Min Ju, Wu, Xuangao, Yang, Hye Jeong, Yuan, Heng, Huang, Shaokai, Yoon, Sun Myung, Kim, Keun-Nam, Park, Sunmin
• Format: Article
• Language: English
• Subjects: Acetylcholinesterase; Acetylcholinesterase - metabolism; Alzheimer's disease; Amnesia; Amnesia - drug therapy; Animals; Body Weight; Brain - metabolism; Casein; Caseins - metabolism; Chemical compounds; Cholesterol; Citric acid; Cytokines; Dementia; Donepezil; Energy metabolism; Enzymes; Feeding; Function analysis; Gene expression; Glucose; Glycogen; Glycogens; Glycolysis; Hippocampus; Hippocampus - metabolism; Hydrolysates; Impairment; Inflammation; Insulin; Insulin Resistance; Intestinal microflora; Lipids; Male; Maze Learning; Memory; memory deficit; Memory Disorders - chemically induced; Memory Disorders - drug therapy; Memory Disorders - metabolism; Metabolism; Microbiota; mRNA; Nitrogen - metabolism; Oxidative phosphorylation; Oxidative stress; Pattern recognition; Pharmacology; Phosphorylation; porcine brain enzyme hydrolysates; Rats; Rats, Sprague-Dawley; Scopolamine; Scopolamine - adverse effects; Swine; Tricarboxylic acid cycle; Tumor Necrosis Factor-alpha - metabolism; Tumor necrosis factor-TNF
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms23063361

No study has revealed the effect of porcine brain enzyme hydrolysate (PBEH) on memory impairment. We aimed to examine the hypothesis that PBEH intake modulates memory deficits and cognitive behavior in scopolamine (SC)-induced amnesia rats, and its mechanism, including gut microbiota changes, was determined. Sprague-Dawley male rats had intraperitoneal injections of SC (2 mg/kg body weight/day) at 30 min after daily feeding of casein (MD-control), PBEH (7 mg total nitrogen/mL) at 0.053 mL (Low-PBEH), 0.159 mL (Medium-PBEH), 0.478 mL (High-PBEH), or 10 mg donepezil (Positive-control) per kilogram body weight per day through a feeding needle for six weeks. The Normal-control rats had casein feeding without SC injection. PBEH dose-dependently protected against memory deficits determined by passive avoidance test, Y-maze, water-maze, and novel object recognition test in SC-induced rats compared to the MD-control. The High-PBEH group had a similar memory function to the Positive-control group. Systemic insulin resistance determined by HOMA-IR was lower in the PBEH groups than in the Normal-control but not the Positive-control. In parallel with systemic insulin resistance, decreased cholesterol and increased glycogen contents in the hippocampus in the Medium-PBEH and High-PBEH represented reduced brain insulin resistance. PBEH intake prevented the increment of serum TNF-α and IL-1β concentrations in the SC-injected rats. Hippocampal lipid peroxide and TNF-α contents and mRNA TNF-α and IL-1β expression were dose-dependently reduced in PBEH and Positive-control. PBEH decreased the hippocampal acetylcholinesterase activity compared to the MD-control, but not as much as the Positive-control. PBEH intake increased the α-diversity of the gut microbiota compared to the MD-control, and the gut microbiota community was separated from MD-control. In metagenome function analysis, PBEH increased the energy metabolism-related pathways of the gut microbiota, including citric acid cycle, oxidative phosphorylation, glycolysis, and amino acid metabolism, which were lower in the MD-control than the Normal-control. In conclusion, alleviated memory deficit by PBEH was associated potentially with not only reducing acetylcholinesterase activity but also improving brain insulin resistance and neuroinflammation potentially through modulating gut microbiota. PBEH intake (1.5-4.5 mL of 7 mg total nitrogen/mL for human equivalent) can be a potential therapeutic agent for improving memory