Lunasin處理對餵食高脂飲食之C57BL/6J小鼠代謝異常之影響

Abstract

根據流行病學調查，全球肥胖人口日益增多，而肥胖與許多疾病之發生相關。肥胖會影響血糖、血脂與血壓等變化，長期會造成血液生化值異常及胰島素阻抗等現象，為代謝症候群之危險因子。種子胜肽lunasin經研究證實具有抗腫瘤、抗發炎、抗氧化及降膽固醇等生理功能。本研究目的為探討lunasin處裡對飲食誘發肥胖C57BL/6J公鼠之血液生化值、血清與肝臟小分子代謝體的影響；及對C2C12小鼠骨骼肌細胞葡萄糖代謝與胰島素敏感性之影響。第一部分動物實驗共分低脂飲食組 (low fat diet, LF)、高脂飲食組 (high fat diet, HF)、高脂飲食加腹腔注射4及20 mg/kg bw/day lunasin組 (HF+low dose lunasin, HF-LL及HF+high dose lunasin, HF-HL)以及高脂飲食添加富含lunasin之大豆蛋白組 (HF+ lunasin dietary intake, HF-DL)。結果發現，HF-HL組及HF-DL組顯著減緩肥胖小鼠葡萄糖耐受性異常之情形，且HF-HL組有降低血清三酸甘油酯之趨勢。然而lunasin處理對小鼠血糖、胰島素、血脂及肝臟脂質過氧化物則無顯著影響。另外，血液與肝臟小分子代謝體分析結果，HF組相較於LF組，克式循環和糖解作用中間產物及嘌呤代謝終產物uric acid顯著增加，且膽酸合成及膽固醇代謝相關及參與胺基酸代謝等小分子顯著下降。而lunasin處理能調節肥胖小鼠肝臟TCA cycle和糖解作用之中間產物及uric acid異常增加之情形，亦可改善肥胖小鼠血清及肝臟中參與胺基酸代謝之小分子下降之現象。第二部分細胞實驗探討lunasin介入對C2C12小鼠骨骼肌細胞之葡萄糖代謝，結果發現，lunasin處理能顯著增加C2C12細胞對葡萄糖之利用，但不影響到胰島素阻抗之表現。綜合上述，動物實驗中，HF-HL及HF-DL組可減緩肥胖小鼠葡萄糖耐受性異常推測可能經由調節血清與肝臟小分子代謝進而改善肥胖小鼠部分代謝異常情形。而飲食中添加富含lunasin的大豆蛋白對肥胖小鼠之影響不如腹腔注射lunasin純品效應強烈。而lunasin如何調控肥胖小鼠生理與對骨骼肌細胞葡萄糖代謝影響之相關路徑，值得進一步探討。The worldwide prevalence of obesity has largely increase according to epidemiologic studies. Obesity is related to many diseases, such as metabolic syndrome, and causes physiological changes in blood sugar, blood lipids, blood pressure, metabolic disorders, and insulin resistance. Lunasin, a seed peptide, exerts many bioactive functions including cancer prevention, immune regulation, anti-oxidation and anti-cholesterol. The aim of this study is to investigate the effect of lunasin on serum biochemical analysis, and metabolic profiling of serum and liver in high-fat diet-induced obese C57BL/6J mice. Additionaly, C2C12 skeleton musclecells were invesigated the effect of lunasin on glucose uptake and insulin sensitivity. In vivo, mice were divided to five groups and fed experimental diets, including low-fat diet (LF) or high-fat diet (HF), HF with intraperitoneal injected (IP) with 4 or 20 mg/kg bw/day synthetic lunasin (HF-LL, HF-HL), and supplemented lunasin of natural soy protein isolate in diet (20 mg/kg bw/day, HF-DL). The data has shown that high dose of lunasin IP and lunasin of natural soy protein isolate significantly improve glucose tolerance in obese mice. However, lunasin treatment didn’t affect serum levels of glucose, insulin, TG and cholesterol, and MDA formation in liver of mice. In the metabolic profiling, mice of HF group have shown that the metabolic intermediates of TCA cycle, glycolysis and uric acid were increased, and metabolites related to bile acid and amino acid were decrease compared to the LF group. Lunasin treatment modulated abnormally changes of those metabolites. In vitro, C2C12 cells were treated with synthetic lunasin and lunasin-enriched soy protein isolate. The data has showed that lunasin increased glucose uptake in C2C12 cells, but it doesn’t affect insulin resistance. In conclusion, our results demonstrated that high-dose IP of lunasin and lunasin dietary intake prevented glucose intolerance in obese mice. Lunasin treatment improving metabolic disorders in obese mice were found in metabolic profiling analysis. More research need to be carried out to know the mechanism of metabolic regulation in obese mice and the signaling pathway of glucose homeostasis in mice muscle cells.