| Abstract: | 現今人們因生活作息及飲食習慣的改變，使得罹患肥胖、糖尿病、脂肪肝等代謝症候群之人口比例與日俱增。非酒精性脂肪肝(Non-alcoholic fatty liver disease, NAFLD)主要是因過多脂肪堆積於肝臟所導致，可能會引發肝纖維化、肝硬化，甚至肝癌，因此如何有效減緩NAFLD已成為全球不容小覷的健康議題。根據先前研究顯示，芥菜富含硫代葡萄糖苷(glucosinolate)，具有降血糖、抗氧化、抗發炎及抗癌等多重功效，鑒於硫代葡萄糖苷於減緩脂肪肝生成及不易形成體脂肪之機制尚未釐清，因此本研究擬以動物及細胞實驗模式，探討芥菜及其硫代葡萄糖?萃取物(BGE)能否有效減緩高脂飲食(High-fat diet, HFD)所導致的NAFLD及肥胖情形，並進一步探究其相關機制。在HFD誘導大鼠肥胖之實驗模式中發現，芥菜可透過降體脂、降血脂、促進脂質代謝、抑制肝臟脂肪變性、增加肝臟抗氧化酵素活性及抗發炎等作用減緩HFD所導致的肥胖及肝損傷情形。另外，於動物及細胞實驗中，以western blot分析證實，芥菜及BGE可藉由活化p-AMPK，抑制SREBP-1/FAS、SREBP-2/HMGCoR脂質生成路徑，增加脂質代謝酵素CPT-1與PPARα蛋白之表現，進而降低脂肪堆積於肝臟，此外，芥菜及BGE可藉由抑制TNF-α、NF-κB，執行其抗發炎作用，以減緩NAFLD。而3T3-L1脂肪前驅細胞分化模式中則發現，BGE可透過抑制脂肪分化因子SREBP-1及PPARγ之表達，降低脂肪的分化能力。綜述以上結果，本研究證實芥菜及BGE具減緩NAFLD與降低體脂肪之功效，期望未來能應用於護肝及減肥相關保健食品的開發，為人民健康把關。
Nowadays, due to changes in people’s lifestyle and dietary habits, the proportion of metabolic diseases such as obesity, diabetes and fatty liver have increased with each passing day. Non-alcoholic fatty liver disease (NAFLD) is mainly characterized by excessive fat accumulation in the liver. It has been suggested that NAFLD spans a spectrum of disease from hepatic steatosis to nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). Therefore, how to effectively ameliorates NAFLD and reduces the body fat formation becoming a global issue that we should not be underestimated. According to previous studies, Brassica juncea is rich in glucosinolates, which have been proven to possess many potential pharmacological properties, including hypoglycemic, anti-oxidation, anti-inflammatory and anti-carcinogenic activities. However, the potential effects of glucosinolate and the mechanism of its action in against HFD-induced NAFLD and obesity remain unclear. Therefore, this study aim to investigate whether Brassica juncea and its glucosinolate extracts (BGE) have anti-obesity and hepatoprotective effects against HFD-induced NAFLD and further explore the mechanism underlying this process in vivo and in vitro. Brassica juncea treatment significantly reduced body fat, dyslipidemia, hepatic steatosis, liver injury, inflammation and by reversing the decreased expression of antioxidant enzyme activity to attenuate oxidative stress in HFD-fed rat liver. Moreover, Brassica juncea and BGE enhanced the activation of AMPK to reduce numerous lipogenic-related proteins, such as SREBPs, FAS and HMGCoR, but increase the expression of lipolysis-related proteins including CPT-1 and PPARα to attenuate hepatic steatosis. Additionally, Brassica juncea and BGE also could ameliorate NAFLD by inhibiting TNF-α and NF-κB to anti-inflammatory. Furthermore, BGE also efficiently suppressed the expression of SREBP-1c and PPAR-γ proteins to reduce the differentiation of 3T3-L1 preadipocytes. Based on the above results, this study demonstrates Brassica juncea and BGE reverse HFD-induced obesity, hepatic steatosis and liver injury could therefore represent an unprecedented hope toward improved strategies for NAFLD and obesity. We expected BGE can be applied to the development of hepatoprotective or anti-obesity nutrient food and keep close tabs on people's health in the future. |
