阿斯匹靈改善倉鼠因長期高脂高膽固醇飼料所造成之肝臟發炎

Abstract

非酒精性脂肪肝疾病 (Non-alcoholic fatty liver disease, NAFLD) 是一系列疾病進程的總稱：包含單純脂質堆積 (Steatosis)、非酒精性脂肪肝炎 (Non-alcoholic steatohepatitis, NASH) 與更嚴重的肝纖維化 (Liver fibrosis) 及肝硬化 (Cirrhosis)。其中由脂質堆積進展到 NASH 是 NAFLD 往更嚴重病程惡化的關鍵。過去文獻與實驗室游盈甄學姊的研究結果發現，阿斯匹靈可抑制 NF-κB 路徑。NF-κB 路徑被視為是引起 NASH 的關鍵促發炎路徑之一，而阿斯匹靈 (又名乙醯水楊酸, Acetylsalicylic acid, ASA) 是一種常見且普遍應用於臨床的非類固醇消炎藥，先前游盈甄學姊的實驗結果顯示，在高油高膽固醇飼料 (HF diet) 誘發 NASH 的倉鼠動物模式中，飼料中添加 0.01% ASA 經過 6 週與 10 週餵養，可抑制 NF-κB 活化與降低血脂。而由於 NAFLD 為慢性且早期幾乎無症狀，於是我們想瞭解 ASA 是否在長期的處理下還可具有延緩 NASH 進展的效果。因此本實驗測試在60週的高油高膽固醇飼料 (HF diet) 誘發 NASH 的倉鼠動物模式中，ASA 是否可改善NASH的進展。此實驗將黃金敘利亞倉鼠分為兩組，分別為餵食高油高膽固醇飼料的 HF 組，與 HF 飼料中外加 0.01% ASA 的 HF + ASA 組。結果顯示，餵食 60 週後相較於 HF 組，HF + ASA 組除了可降血漿總膽固醇，也會降低相關促發炎細胞激素：TNF-α、IL-1β 與 IL-6 之 mRNA 表現量與 IL-1β 之蛋白量，達到抗發炎的效果。與 HF 組相比，HF+ASA 組之TGF-βmRNA表現量顯著降低至62%；且肝纖維化評分上也發現，Stage3 等級視野比例降低至 30%。此外，在本次實驗中觀察到 HF 組的肝臟外部形態有白色小突起的構造，而在 HF + ASA 組中則沒有發現。加上HF+ASA組肝臟TGF-α與AFP (α-Fetoprotein)的mRNA表現量也顯著降低至72%與28%，顯示在60週處理下，ASA具有延緩肝纖維化與HCC發生的潛力。不過同時也發現相較於HF組，HF + ASA組會提高CD36 mRNA的表現量，而CD36有文獻指出被認為是促發炎因子。雖然如此，本實驗發現整體而言，ASA的抗發炎潛力大於促發炎潛力，至於抗發炎與促發炎兩者間的交互作用有待未來後續實驗進一步深入探討。

Nonalcoholic fatty liver disease (NAFLD), is a spectrum of liver disease in the absence of excessive alcohol consumption, includes simple steatosis, nonalcoholic steatohepatitis (NASH), fibrosis and ultimately cirrhosis. Progress of simple steatosis to NASH is the key point for NAFLD progressing to more severe stages. Previous studies showed that Aspirin inhibited NF-κB pathway, which has been considered one of the key proinflammatory signaling pathway that leads to NASH. Moreover, Aspirin, also known as acetylsalicylic acid (ASA), is one of the commonly used nonsteroidal anti-inflammatory drugs (NSAIDs). It has been widely used in clinical practice. Our previous data showed that ASA inhibited NF-κB activation and decreased plasma lipids in HFC diet-induced NASH in hamsters in 6 and 10 weeks studies. NAFLD is a chronic disease and there is few or no symptom in the early stage; therefore, the aim of this study is to investigate if ASA is able to delay progression to NASH in a long-term period. In this study, we tested if ASA able to improve NASH in the hamster model fed with HF diet for 60 weeks. Golden Syrian hamsters were fed with high fat high cholesterol diet (HF) or HF diet supplemented with 0.01% ASA (HF + ASA) for 60 weeks. The results show that compared to the HF group, ASA not only lower plasma levels of total cholesterol but also lower the levels of TNF-α, IL-1β, IL-6 mRNA and the protein level of IL-1β in the liver. Furthermore, the levels of TGF-1 mRNA in HF+ASA group was 62% of that in the HF group, and the Stage3 fibrosis score was 30% of that in the HF group. In addition, white spots on the surface of livers in HF group, but they were not found in livers in HF + ASA group. Moreover, the levels of hepatic TGF-and -fetoprotein (AFP) mRNA in the HF+ASA group were 72% and 28%, respectively, of that in the HF group. These data suggest that ASA tend to delay the progression of liver fibrosis and HCC. However, compared to the HF group, ASA also increased hepatic mRNA levels of CD36 which has been considered a proinflammatory factor. Nevertheless, the anti-inflammatory potential is stronger than proinflammatory potential in the HF+ASA group than in the HF group. Investigation of the interaction between anti-inflammatory and proinflammatory effects of ASA can be planned in the future.