抹草萃取物改善肝臟脂質堆積之體內外研究

The inhibitory effect of Desmodium caudatum extract on hepatic lipid accumulation in vivo and in vitro

張綺紋(Chi-Wen Chang)

指導教授 ： 陳璟賢

中山醫學大學/健康管理學院/營養學系/碩士(2021年)

https://doi.org/10.6834/csmu202100189

摘要

非酒精性脂肪肝病(nonalcoholic fatty liver disease, NAFLD)為一種慢性肝病，包含肝臟脂質過度堆積或脂肪變性等病徵。過去的研究中發現，抹草萃取物(Desmodium caudatum extract,DCE)具有抗發炎、抗氧化和抗癌等功效，但目前尚未有DCE改善NAFLD之研究。故本研究以體內外實驗來探討DCE改善NAFLD之能力，先以細胞模式探討DCE減少肝臟細胞HepG2中的脂肪堆積作用，實驗結果顯示DCE可降低油酸(oleic acid, OA)誘導之HepG2細胞內脂肪堆積，並增加肝醣儲存量。再由西方墨點法發現DCE可透過磷酸化AMPK (5' adenosine monophosphate-activated protein kinase)進而降低HMGCR (Hydroxymethylglutaryl-CoA reductase)及ACC (Acetyl-CoA carboxylase)蛋白表現量並抑制膽固醇和三酸甘油脂合成；DCE可增加CPT-1 (Carnitine palmitoyltransferase I)及GSK3β (Glycogen synthase kinase 3 beta)關鍵酵素的表現以促進脂肪酸氧化和肝醣合成。接續以高脂飲食(high fat diet, HFD)合併鏈脲佐菌素(streptozotocin, STZ)誘發C57BL/6小鼠作為NAFLD之實驗動物模式，每日管餵給予100 mg/kg和200 mg/kg之DCE 持續6週進行實驗，並以辛伐他汀(simvastatin)與鹽酸二甲雙胍(metformin hydrochloride)作為實驗對照組，犧牲後分析血清生化數值發現，相較於誘導組，100 mg/kg DCE組能有效降低空腹血糖值，而200 mg/kg DCE 組則是能顯著降低總膽固醇與三酸甘油酯。進一步將肝臟組織進行病理切片發現，DCE可減少肝臟的脂肪堆積，上述結果皆與細胞實驗結果一致。總結，經由體內外實驗證實，DCE可減少肝臟內脂肪堆積，並調節肝醣代謝，未來可應用於輔助治療非酒精性脂肪肝。

關鍵字

非酒精性脂肪肝 ； 抹草 ； 肝臟細胞 ； 脂質堆積 ； 肝醣代謝

並列摘要

Nonalcoholic fatty liver disease (NAFLD) is a major cause of chronic liver disease, including excessive accumulation of cholesterol, triglycerides, or steatosis in the liver. Desmodium caudatum extract (DCE) has been shown to possess anti-inflammatory, anti-oxidant, and anti-cancer activities, but there isn’t much research on improving NAFLD. Therefore, we aimed to investigate the anti-NAFLD effect of DCE. Human hepatocytes HepG2 cells co-treated with oleic acid (600 μM) and DCE were designed to be an in vitro model. The result indicated that DCE could reduce oleic acid-induced lipid accumulation, and reverse glycogen storage in HepG2 cells. Western blotting found that DCE could decrease HMGCR (Hydroxymethylglutaryl-CoA reductase), ACC (Acetyl-CoA carboxylase) to suppress cholesterol and triglycerides synthesis, and stimulated expression of CPT-1 (Carnitine palmitoyltransferase I), and GSK3β (Glycogen synthase kinase 3 beta) for activating fatty acid β-oxidation and glycogen synthesis by phosphorylation of AMP-activated protein kinase (AMPK). In vivo, the NAFLD animal model was induced by continuous high-fat diet feeding and low-dose streptozotocin (STZ) for five days. 100 and 200 mg/kg DCE, simvastatin, or metformin were given for 6 weeks after STZ injection. The results revealed that 100 mg/kg DCE can improve fasting blood glucose, while 200 mg/kg DCE can decrease significantly the serum levels of total cholesterol and triglycerides. Further, histologic examination revealed the lipid accumulation in the liver decreased by DCE treatment. In summary, DCE can reduce lipid accumulation in the liver and increase glycogen content, and it can be used in the treatment of NAFLD.

並列關鍵字

non-alcoholic fatty liver ； Desmodium caudatum ； liver cells ； lipid accumulation ； Glycogen metabolism

參考文獻

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