阿斯匹靈及黃連素減輕倉鼠因高脂高膽固醇飼料所引起的非酒精性脂肪肝炎

Aspirin and berberine ameliorate high-fat/high-cholesterol diet induced Nonalcoholic Steatohepatitis (NASH) in hamsters

游盈甄(Ying-Chen Yu)

指導教授 ： 呂紹俊

國立臺灣大學/醫學院/生物化學暨分子生物學研究所/碩士(2015年)

https://doi.org/10.6342/NTU.2015.10321

摘要

非酒精性脂肪肝 (Nonalcoholic fatty liver；NAFLD) 為最常見的慢性肝臟疾病。其病程有不同嚴重程度的發展，由單純的脂肪堆積，到較嚴重的非酒精性脂肪肝炎 (Nonalcoholic stetohepatitis；NASH)、肝纖維化，甚至到肝硬化。許多動物模式的研究也都指出飲食中脂肪，尤其是膽固醇，是肝臟從脂肪堆積演變成NASH的重要因素。而實驗室學長利用高脂高膽固醇飼料餵食倉鼠，建立了新的NASH動物模式。
黃連素 (Berberine；BBR) 是植物性生物鹼，已被證實可以藉由增加LDL受器蛋白表現量，進而降低血液中LDL-膽固醇，被認為是機轉不同於Statin類藥物的降血脂藥。阿斯匹靈 (Aspirin；ASA) 是非類固醇消炎藥的一種，報導指出可以改善肥胖大鼠的高血糖及血脂異常等症狀。我的實驗目的是要探討在倉鼠的NASH動物模式中，BBR及ASA是否能夠改善NASH的症狀。
首先，我們以高脂高膽固醇飼料餵食的倉鼠動物模式，評估ASA及BBR是否有抑制NASH的功效。倉鼠餵食一般chow diet或高脂高膽固醇的飼料 (HFC) 以及HFC添加ASA (HFC＋ASA)或BBR (HFC+BBR)，為期10週。結果顯示ASA及BBR兩者皆會降低血漿膽固醇、三酸甘油酯濃度以及ALT、AST活性。透過膠體過濾法分析，顯示HFC+ASA及HFC+BBR組的VLDL-、LDL-膽固醇含量都低於HFC組的倉鼠；肝臟病理切片分析，觀察到在HFC+ASA及HFC+BBR組的發炎程度也低於HFC組的倉鼠。本次實驗顯示降膽固醇藥以及抗發炎藥可以減緩NAFLD進展成NASH的程度。
由於實驗一的動物每組只有3隻，因此我們再進行一個動物實驗去驗證ASA及BBR抑制NAFLD進展成NASH的功效。在餵食6週後，結果顯示BBR仍然可降低血漿膽固醇、三酸甘油酯濃度以及ALT、AST活性。而ASA仍明顯降低ALT、AST活性，但並無降低血液膽固醇、三酸甘油酯濃度的作用。然而，ASA及BBR共同處理並沒有加成效果。不過仍然觀察到HFC+ASA及HFC+BBR的倉鼠，其肝臟發炎和纖維化程度都低於HFC組的倉鼠。除此之外，在免疫組織染色中觀察到，與HFC組倉鼠相比，HFC+ASA及HFC+BBR兩組NF-κB訊號都有明顯減少。本次實驗顯示ASA及BBR可以抑制NF-κB活化，另外BBR可以提高LDLR降低血液膽固醇，進而減輕倉鼠因高脂高膽固醇飼料而誘導的NASH。

關鍵字

非酒精性脂肪肝 ； 非酒精性脂肪肝炎 ； 阿斯匹靈 ； 黃連素 ； NF-κB ； 膽固醇

並列摘要

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide. NAFLD has a wide histologic spectrum ranging from simple steatosis, nonalcoholic steatohepatitis (NASH), to fibrosis and cirrhosis. Recent studies indicate that dietary lipid, especially cholesterol, is a critical factor of the development of NASH. An NASH animal model, by feeding golden Syrian hamster with high-fat/high-cholesterol (HFC) diet, is established in our laboratory.
Berberine (BBR) is a plant alkaloid, and has been demonstrated to lower cholesterol by increasing LDL-receptor; the mechanism of action is different from that of statins. Aspirin (ASA) is a nonsteroidal anti-inflammatory drug, has been reported to reverse hyperglycemia and dyslipidemia in obese rodents. In this study, we aim to test if BBR and ASA able to improve NASH in the hamster model.
In the first animal experiment, golden Syrian hamsters were fed with chow diet, or high fat-cholesterol diet (HFC), HFC+ASA diet or HFC+BBR diet for 10 weeks. The results show that both ASA and BBR lower plasma levels of cholesterol, triglycerides, alanine aminotransferase (ALT), aspartate aminotransferase (AST). And gel-filtration analysis of the lipoprotein profile reveals that both ASA and BBR decrease cholesterol levels in VLDL and LDL fractions compared with that in the HFC-fed hamsters. Histopathological analyses of liver showing that hamsters treated with ASA and BBR have lower inflammation level than hamsters in the HFC group. Our results in this study suggest that cholesterol-lowering drug and anti-inflammatory drug may help to alleviate the severity of NASH in HFC fed hamsters.
Because every experimental group has only 3 hamsters, we then carried out another animal experiment to evaluate the effects of ASA and BBR. In this study 6 hamsters in each group were fed the experimental diets for 6 weeks. The results show that BBR still lowers plasma levels of cholesterol, triglycerides, ALT and AST. And ASA lowers ALT, AST, but it has no effect on plasma levels of cholesterol and triglycerides. However, there is no additive effect in ASA+BBR group. The hamsters in HFC+ASA and HFC+BBR groups exhibit less hepatic inflammation and fibrosis than the hamsters in HFC group. Furthermore, immunohistochemistry stain showing that both ASA and BBR reduced hepatic NF-κB signals compared with that in HFC group. Our results in this study suggest that ASA and BB inhibited NF-κB activation and decreased plasma lipids and thus alleviate inflammation in HFC diet-induced NASH in hamsters.

並列關鍵字

NAFLD ； NASH ； Aspirin ； Berberine ； NF-κB ； cholesterol

參考文獻

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