大豆蛋白對非酒精性脂肪變性肝炎影響機制之探討

Mechanisms of the Beneficial Effects of Soy Protein on Non-Alcoholic Steatohepatitis

邱詩涵(Shih-Han Chiu)

指導教授 ： 陳俊榮

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(2008年)

摘要

摘要
本研究室先前發現以大豆蛋白取代酪蛋白作為大鼠飼料中50%的蛋白質來源時，可延緩非酒精性脂肪變性肝炎 (non-alcoholic steatohepatitis, NASH) 疾病進程之作用。本研究誘發大鼠NASH後，將實驗組飲食中的蛋白質來源改為大豆蛋白或大豆蛋白胃蛋白酶水解物，以探討大豆蛋白中可改善NASH的功效成分及機制。實驗共進行18週，前12週為誘發飲食期，後6週為實驗飲食期。C組於實驗進行中全程餵食AIN-93M標準飲食，其餘所有動物於誘發飲食期間餵食NASH誘發飲食，實驗飲食期則將分別餵予各組實驗飼料，包括：N 組 (NASH誘發飲食)、NA組(NASH誘發飲食 + 大豆蛋白SPI )、 NS 組 (NASH誘發飲食 + 大豆蛋白水解物水溶性成分SSP)及NP 組 (NASH誘發飲食 + 大豆蛋白水解物非水溶性成分 PSP)。結果顯示，飼料中添加大豆蛋白及大豆蛋白水解物，可顯著降低NASH大鼠口服葡萄糖後血漿葡萄糖濃度、肝臟中總膽固醇、三酸甘油酯及游離脂肪酸濃度，但肝臟中PPAR-α、PPAR-γ蛋白質表現量在各組間並無顯著差異。另一方面，添加大豆蛋白及其水解物的實驗組中，肝臟CYP2E1、CYP4A蛋白質表現、TNF-α及Hydroxyproline濃度皆顯著低於N組。由研究結果推論，大豆蛋白及其水解物皆可在不影響 PPAR-α、PPAR-γ蛋白質表現的路徑下，藉由降低胰島素抗性、減少肝臟脂質堆積並可改善氧化壓力、肝臟發炎情形，進而延緩肝細胞走向纖維化，達到延緩 NASH 疾病進程之作用。

關鍵字

非酒精性脂肪變性肝炎 ； 大豆蛋白 ； 胰島素抗性 ； PPARs ； 氧化壓力

並列摘要

Abstract
In the previous study, we found that fed rats with diet containing soy protein as 50% of the protein dietary protein source instead of casein significantly retarded the progression of non-alcoholic steatohepatitis (NASH). Therefore, our objective of the study is to investigate the mechanisms and effective components of soy protein on NASH. In this study, rats were induced to have steatohepatitis with liquid high fat diet for 12 weeks and divide into four experiment groups for 6 weeks. Diets of the experiment groups contain soy protein or pepsin-digested soy protein (hydrophobic or hydrophilic fraction) as substitution of part of casein. Results showed that diets containing soy protein isolate or soy protein hydrolysates could significantly decrease insulin resistance, hepatic lipid of total cholesterol, triglycerides and free fatty acid and reduced the concentrations of lipid peroxides, but all groups had no significantly different in contents of hepatic PPAR-α and PPAR-γ protein. Additionally, soy protein isolate and soy protein hydrolysates intake lowered hepatic CYP2E1, CYP4A protein expression, TNF-?? and hydroxyproline concentration. In conclusion, soy protein isolate and soy protein hydrolysates may improve the liver function in patients with NASH by lowering liver lipid levels, decreasing oxidative stress and improving insulin resistance but not result from the changes of PPAR-α and PPAR-γ protein expression.

並列關鍵字

NASH ； soy protein ； insulin resistance ； PPARs ； oxidative stress

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