介入富含n-3多元不飽和脂肪酸之油脂對大鼠非酒精性脂肪肝疾病與粒線體功能之影響

Effects of oils rich in n-3 polyunsaturated fatty acids on non-alcoholic fatty liver disease and mitochondrial function in rats

蔡偉恩(Wei-An Tsai)

指導教授 ： 謝榮鴻

臺北醫學大學/公共衛生暨營養學院/保健營養學研究所/碩士(2014年)

摘要

非酒精性脂肪肝疾病為非過量攝取酒精或非特殊原因造成脂肪堆積於肝臟，其主要成因之一為不當日常飲食習慣，當飲食中過多脂肪被攝入時，因送入肝臟三酸甘油酯過多，過度增加肝臟粒線體β氧化產生活性氧屬，攻擊肝臟細胞，使脂肪酸氧化降低；且極低密度脂蛋白無法有效將三酸甘油酯運送出肝臟，使其堆積於肝臟內，最終造成非酒精性脂肪肝疾病。n-3多元不飽和脂肪酸為碳基端算起第3個碳含雙鍵之不飽和脂肪酸，其功能為穩定細胞膜、訊號傳遞及能量儲備等。過去針對n-3 多元不飽和脂肪酸研究發現，其可改善血脂組成、胰島素抗性、調節脂質代謝基因並降低發炎反應等功效。常見之n-3 多元不飽和脂肪酸為α-次亞麻油酸、二十碳五烯酸以及二十二碳六烯酸，本次實驗之油脂使用為磷蝦油、魚油及亞麻籽油；而磷蝦油與魚油富含二十碳五烯酸及二十二碳六烯酸，亞麻籽油則富含α-次亞麻油酸。
實驗目的為探討磷蝦油、魚油、亞麻籽油等富含n-3 多元不飽和脂肪酸油脂介入以45 %高脂飲食誘發非酒精性脂肪肝疾病之Sprague-Dawley (SD)大鼠，對其血脂、肝臟脂肪、脂肪酸生成酵素活性、抗氧化酵素活性及粒線體功能之影響。實驗共分8組：控制組－C，高脂組－HF，磷蝦油一、三倍劑量組－KO1、3，魚油一、三倍劑量組－FO1、3，亞麻籽油一、三倍劑量組－LO1、3。除C組外，其餘組別皆給予高脂飲食；除C、HF組外，其餘組別介入不同種類及劑量之油品；而一倍、三倍劑量組別分別將其n-3總量固定為每天每克飼料4.2及13.0 毫克。12週後犧牲，取其血液及肝臟樣本進行後續分析。其結果入下， FO及LO組於血漿三酸甘油酯濃度顯著低於HF組；而胰島素抗性部分則HF、KO3、FO3顯著高於C組。KO1、FO1及LO組於肝臟三酸甘油酯濃度與病理切片有顯著改善。脂肪酸生成酵素活性為KO3及FO3組顯著高於C組。抗氧化酵素、粒線體呼吸鏈複合體酵素活性及粒線體生合成則為KO1、FO1及LO組顯著高於HF組。
以45 %高脂飲食成功誘發大鼠非酒精性脂肪肝疾病模式下，同時額外添加富含n-3多元不飽和脂肪酸油脂磷蝦油每天每公斤體重273.4毫克、魚油每天每公斤體重149.6毫克、亞麻籽油每天每公斤體重147.0與466.5毫克，其可降低血脂、肝臟脂肪與脂肪酸生成酵素活性，提升肝臟抗氧化能力與粒線體功能，達到延緩或預防非酒精性脂肪肝疾病之進展。

關鍵字

非酒精性脂肪肝疾病 ； 粒線體 ； 磷蝦油 ； 魚油 ； 亞麻籽油

並列摘要

Non-alcoholic fatty liver disease (NAFLD) is a condition of fat accumulatuin in the liver in the absent of excessive alcohol consumption (less than 20 g per day) and specific causes of hepatic steotosis. An improper dietary habit is one of the factors which induce NAFLD. When consuming too much fat, it will increase triglyceride into liver for metabolism. Meanwhile liver mitochondrial β oxidation increases and produces more reactive oxygen species, which may harm hepatic cells. On the other hand, very low-density lipoprotein can not bring triglyceride out of liver efficiently, and caused NAFLD eventually. n-3 polyunsaturated fatty acid (n-3 PUFA) is a polyunsaturated fatty acid which fist double bond is at third carbon from carbonyl tail. Its physiological functions include cell membrane maintenance, signal transduction, and energy storage. n-3 PUFA’s studies indicated that n-3 PUFA may ameliorate dyslipidemia, insulin resistance, regulate lipid metabolic genes, and reduce inflammatory response. α-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) are the menbers of n-3 PUFA’s family. In our study, krill oil, fish oil, and linseed oil, which were rich in n-3 PUFA, were used for supplement. Krill oil and fish oil contain EPA and DHA, while linseed oil contains ALA. The purpose of this experiment is to evaluate supplement with oils rich in n-3 PUFA, such as krill oil, fish oil and linseed oil, on plasma and liver lipid profiles, liver fatty acid synthesis enzyme activities, antioxidant enzyme activities, and mitochondrial function in the animal model of NAFLD induced by 45 % high fat diet. 80 Sprague-Dawley (SD) rats were divided into 8 groups, including control group (C), high fat diet group (HF), high fat diet supplied with krill oil, fish oil or linseed oil in one or triple dosage respectively (KO1, KO3, FO1, FO3, LO1, LO3). Except C, rests of the groups were fed with Adjusted Calories Diet (45/Fat) fodder. Except C and HF, rests of the groups were supplied with different oil and different dosage. One and triple dosage were used to control their supplement n-3 PUFA amount, which were 4.2 and 13.0 mg/g fodder/day respectively. After 12 weeks, SD rats were sacrified and analyzed plasma lipid profiles and glucose homeostasis, hepatic lipid profiles, biopsies, fatty acid synthesis enzyme acitivities, antioxidant enzyme activites, mitochondrial respiratory chain complex enzyme activities, and mitochondrial biogenesis. FO1, FO3, LO1, and LO3’s plasma triglyceride were significantly lower than HF. Furthermore, HF, KO3, and FO3’s HOMA-IR increased significantly. KO1, FO1, LO1, and LO3’s hepatic triglyceride content and biopsies were ameliorated significantly. Fatty acid synthesis enzyme activities in KO3 and FO3 were significantly higher than C. Antioxidant enzyme activities, mitochondrial respiratory chain complex enzyme activities, and mitochondrial biogenesis in KO1, FO1, LO1, and LO3 were significantly higher than HF. Supplement with oils rich in n-3 PUFA, such as krill oil 273.4 mg/kg b.w./day, fish oil 149.6 mg/kg b.w./day, and linseed oil 147.0 or 466.5 mg/kg b.w./day may reduce plasma and hepatic lipid profiles, fat accumulation in liver, and fatty acid synthesis; while elevating mitochondrial function, eventually ameliorate NAFLD in animal model induced by 45 % high fat diet.

並列關鍵字

non-alcoholic fatty liver disease ； mitochondrion ； krill oil ； fish oil ； linseed oil

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