核桃仁多糖对果蝇阿尔茨海默病所致衰老的影响

Effect of Walnut Kernel Polysaccharides on Aging Induced by Alzheimer's Disease in Drosophila Melanogaster

摘要:

阿尔茨海默病(Alzheimer's disease,AD)已成为影响老年人生活质量的重要因素。β-淀粉样蛋白42(Aβ₄₂)转基因果蝇是一种转入人源β-淀粉样前体蛋白的AD模式生物。以核桃为原料提取核桃仁多糖,测定其化学组成和单糖组成；以AD果蝇为模型测定核桃仁多糖对AD所致衰老的影响。结果表明,核桃仁多糖能够显著提高Aβ₄₂转基因果蝇的寿命、攀爬指数和摄食量；同时缓解果蝇肠道通透性的下降,降低果蝇脑组织中Aβ₄₂水平、乙酰胆碱酯酶活力以及环磷酸腺苷含量。此外,核桃仁多糖能够有效提高AD果蝇超氧化物歧化酶活力、过氧化氢酶活力,并且降低丙二醛含量；RT-PCR分析结果同样表明,核桃仁多糖在转录水平上显著缓解了Aβ₄₂转基因果蝇脑组织中氧化应激失衡。核桃仁多糖具有缓解AD所致衰老的潜在功效,其机制可能与缓解脑部氧化应激失衡,进而降低脑部Aβ₄₂水平、乙酰胆碱酯酶活力和环磷酸腺苷含量相关。研究旨在为核桃仁多糖在精准营养、特医特膳和功能食品等领域的加工利用提供一定理论基础。

Abstract:

Alzheimer's disease (AD) has become an important factor affecting the quality of life of the elderly. Aβ₄₂ transgenic Drosophila, an AD model organism with human APP (amyloid precursor protein) gene transferred, is one of the models in genetic research. Walnut kernel polysaccharides were extracted from walnuts, and their chemical composition and monosaccharide composition were determined. Using Aβ₄₂ transgenic Drosophila as a model, the effect of walnut kernel polysaccharides on aging induced by AD was investigated. The results showed that walnut kernel polysaccharides significantly prolonged the lifespan, improved the climbing index and food intake of Aβ₄₂ transgenic Drosophila. Meanwhile, the decrease in intestinal permeability was ameliorated, and the levels of Aβ₄₂, acetylcholinesterase activity and cyclic adenosine monophosphate content in the brain tissue of Drosophila were reduced. Additionally, walnut kernel polysaccharides effectively enhanced the activities of superoxide dismutase and catalase, and reduced the content of malondialdehyde in AD Drosophila melanogaster. RT-PCR results also showed that walnut kernel polysaccharides significantly alleviated the imbalance of oxidative stress in the brain tissue of Aβ₄₂ transgenic Drosophila at the transcriptional level. In conclusion, walnut kernel polysaccharides have the potential to alleviate aging caused by AD, and the mechanism might be related to relieving brain oxidative stress imbalance, thereby reducing Aβ₄₂ levels, acetylcholinesterase activity and cyclic adenosine monophosphate content. This study aimed to provide a theoretical basis for the processing and utilization of walnut kernel polysaccharides in the fields of precision nutrition, special medical diets and functional foods.