補充蒟蒻纖維及菊糖寡醣對於Sprague-Dawley大鼠抗氧化狀態及脂質代謝之影響

Effects of konjac and inulin fiber on antioxidative status and lipid metabolism in Sprague-Dawley rats

李伊姍(Yi-Shan Li)

指導教授 ： 陳曉鈴

中山醫學大學/健康管理學院/營養學研究所/碩士(2011年)

摘要

目的:本實驗主要目的在探討補充蒟蒻纖維(konjac glucomannan, KGM)及菊糖寡醣(inulin) 於無纖維飼料中對Sprague Dawley(SD)大鼠血液、肝臟脂質代謝及相關代謝途徑之影響，以及與抗氧化機制之影響。
材料方法:將5週齡雄性SD大鼠隨機分成三組：無纖維組(fiber-free, FF)、蒟蒻組(KGM)及菊糖組(inulin)。實驗飼料配方參考AIN-76配方，其中無纖維組不添加纖維素，其餘兩組則添加5 %蒟蒻或菊糖。實驗期間為28天，飼料及飲水皆採自由攝食方式，並於每日記錄其攝食量，體重則每週記錄兩次。犧牲前兩天，連續收集48小時新鮮糞便並定量糞便菌數。犧牲前禁食24小時，以CO2昏迷後採集血液以分析血液淋巴球DNA損傷和血漿脂質濃度和脂質過氧化物丙二醛(malonaldehyde)及維生素E，並切取組織以測定肝臟脂質含量、脂質過氧化物以及脂質代謝相關基因表現、小腸黏膜抗氧化酵素基因表現、盲腸內容物短鏈脂肪酸濃度及大腸組織前、後段丙二醛濃度。
結果: 添加KGM顯著降低血漿總膽固醇、低密度脂蛋白膽固醇及三酸甘油脂濃度；添加inulin則顯著減少血漿低密度脂蛋白膽固醇及三酸甘油脂濃度，但兩種纖維皆不影響血漿高密度脂蛋白膽固醇濃度。肝臟脂質方面，三組之總膽固醇及三酸甘油脂含量無顯著差異。肝臟脂質代謝相關基因表現方面，添加KGM顯著提升HMG CoA reductase、cholesterol 7-alpha-hydroxylase、LDL receptor、peroxisome proliferator-activated receptor α基因表現，但不影響fatty acid synthase、AMP-activated protein kinase α2及SREBP-cleavage activating protein 7基因表現。而inulin只顯著提升SREBP-cleavage activating protein 7表現。在抗氧化效應方面，添加KGM可明顯降低血液淋巴球細胞DNA損傷。血漿丙二醛濃度在補充蒟蒻及菊糖纖維有降低趨勢，但無統計上的顯著差異。血漿維生素E濃度，經總脂質校正後，KGM組可明顯提升其濃度。Inulin顯著降低近端大腸丙二醛濃度，KGM則顯著降低遠端丙二醛濃度。在肝臟丙二醛方面，三組之總膽固醇及三酸甘油脂含量無顯著差異。而在肝臟GSH酵素，inulin組濃度明顯高於FF及KGM組。抗氧化基因表現方面，KGM可明顯增加肝臟glutathione peroxidase基因表現；inulin則增加肝臟及小腸黏膜的superoxide dismutase與catalase基因表現。本研究發現添加KGM及inulin皆增加盲腸短鏈脂肪酸濃度及含量。糞便菌相上，KGM及inulin提升Lactobacilli spp.濃度及每日糞便Bifidobacterium spp和Lactobacilli spp.的排出量，並且有效抑制壞菌Clostridium spp.。
結論；本研究結果顯示，補充蒟蒻纖維及菊糖寡醣於正常脂肪無纖維飼料可能藉由調控肝臟脂質基因表現而有效降低血液脂質。此外這兩種膳食纖維有效降低血液氧化壓力、並提升血液、肝臟及腸道黏膜細胞之抗氧化機制。

關鍵字

蒟蒻纖維 ； 菊糖寡醣 ； 脂質代謝相關基因 ； 短鏈脂肪酸

並列摘要

Objective: The main purpose of this study supplement konjac fiber (konjac glucomannan, KGM) and inulin oligosaccharides (inulin) in the non-fiber feed to the Sprague Dawley (SD) rat blood, liver lipid metabolism and related metabolic pathways of influence, as well as the impact of antioxidant mechanisms.
Materials and Methods: The 5-week-old male SD rats were randomly divided into three groups: non-fiber group (fiber-free, FF), Konjac group (KGM) and the inulin group (inulin). Experimental reference AIN-76 formula feed formula, which does not add non-cellulose fiber group, the other two groups are added 5% konjac or inulin. Experimental period of 28 days, feed and water are collected free feeding method, and record their daily food intake, body weight is recorded twice a week. Two days before sacrifice, a continuous collecting 48 hours of fresh manure and quantitative fecal bacteria. Fasting 24 hours before sacrifice, after the capture of CO2 a coma for analysis of blood lymphocyte DNA damage in blood and plasma lipid levels and malondialdehyde (malonaldehyde) and vitamin E, and cut tissue to determine the liver lipid content, lipid oxide and lipid metabolism-related gene expression, small intestinal mucosa antioxidant enzyme gene expression, the contents of the cecum concentration of short-chain fatty acids and colorectal tissue before and after the section of malondialdehyde concentration.
Results: Adding KGM significantly lower plasma total cholesterol, LDL cholesterol and triglyceride levels; added inulin is significantly reduced plasma low-density lipoprotein cholesterol and triglyceride levels, but the two simply can not influence plasma high-density fiber lipoprotein cholesterol concentrations. Liver lipids, the three groups of total cholesterol and triglyceride levels were not significantly different. Liver lipid metabolism-related gene expression, the added KGM significantly enhance HMG CoA reductase, cholesterol 7-alpha-hydroxylase, LDL receptor, peroxisome proliferator-activated receptor α gene expression, but does not affect the fatty acid synthase, AMP-activated protein kinase 2 and SREBP-cleavage activating protein 7 gene expression. Only inulin significantly enhance SREBP-cleavage activating protein 7 expression. In terms of antioxidant effects, KGM can significantly reduce blood lymphocyte DNA damage. Plasma malondialdehyde concentration in KGM and inulin groups tended to decrease, but no statistically significant difference. Plasma vitamin E concentrations, the total lipid-corrected, KGM group can significantly enhance their concentration. Inulin significantly reduced malondialdehyde concentration of proximal colon, and KGM is significantly reduced malondialdehyde concentration. There were not significantly different on the concentration of
liver MDA total cholesterol and triglyceride. GSH in liver, inulin group were significantly higher than FF and KGM Groups. Antioxidant gene expression in, KGM can significantly increase liver glutathione peroxidase gene expression; inulin increased liver and intestinal mucosa of superoxide dismutase and catalase gene expression. The study found that adding both KGM and inulin increased cecal short-chain fatty acid concentration and content. On fecal microflora, KGM, and inulin improve Lactobacilli spp. concentrations and daily fecal Bifidobacterium spp and Lactobacilli spp.'s excretion, and inhibit bad bacteria Clostridium spp..
Conclusion: Results of this study show that added konjac fiber and inulin oligosaccharides in normal fat-free fiber diet may be through regulation of gene expression and hepatic lipid effectively reduce blood lipids. In addition, both dietary fiber reduce blood oxidative stress, and increase the blood, liver and intestinal mucosa cells of anti-oxidation mechanism.

並列關鍵字

Konjac fiber ； inulin oligosaccharides ； lipid metabolism-related genes ； short-chain fatty acids

參考文獻

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