UM E-Theses Collection (澳門大學電子學位論文庫)
Title
Protective effects of Penthorum chinense Pursh against alcohol-induced liver injury in mice
English Abstract
Consistent, excessive alcohol consumption leads to alcoholic liver disease (ALD), ranging from hepatic steatosis to hepatitis, progressive fibrosis, cirrhosis and hepatocellular carcinoma. ALD has been considered to be a major cause of mortality among people with alcohol abuse. Despite severe health impact of ALD, there is still no satisfactory therapy to prevent or reverse the pathogenesis and progression of ALD, except the abstinence from alcohol. In the past years, herbal medicines have received the considerable attention as potential agents for the prevention and treatment of ALD, due to their multi-target actions and less side effects. Penthorum chinense Pursh (PCP, Penthoraceae), a Miao ethnomedicine, has been used as functional food and folk medicine for the treatment of jaundice, cholecystitis, oedema and infectious hepatitis. The tea made from the whole plant of PCP is becoming popular among the bartenders in local wineries and local residents who often drink wine. The present study is aimed to investigate the probable protective effect of aqueous extract of P. chinense against ethanol-induced liver injury in vivo and their molecular mechanisms. Two alcohol feeding models, including chronic and acute ethanol-induced liver injury, were used to examine the effects of P. chinense in our study. In chronic ethanol-induced liver injury model, mice were fed a Lieber-DeCarli liquid diet containing alcohol or isocaloric maltose dextrin as control diet with or without aqueous extract of P. chinense (PCP, 5.15 and 10.30 g/kg/BW) for 4 weeks. Silymarin (86 mg/kg) was used as positive control to compare the efficacy of PCP against chronic ethanol-induced induced hepatotoxicity. In acute alcohol-induced liver injury model, male C57BL/6 mice were treated with aqueous extract of PCP (5.2 and 10.3 g/kg BW) once daily for 7 consecutive days priors to ethanol gavage (4.7 g/kg) every 12 h for a total of three doses. Both in chronic and acute alcoholic liver injury models, treatment with PCP significantly decreased the elevation of serum enzyme activities, i.e. alanine aminotransferase (ALT) and aspartate aminotransferase (AST), hepatic lipid accumulation, and inflammatory cytokines (i.e. TNF-α and IL-6), which induced by chronic and acute ethanol exposure. In chronic alcoholic liver injury model, PCP was also found to attenuate reactive oxygen species (ROS) generation and malondialdehyde (MDA) level, restore the glutathione (GSH) depletion, and increase the superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities in liver. Additionally, PCP supplementation (10.30 mg/kg) inhibited the induction of hepatic cytochrome P450 2E1 (CYP2E1), a major contributor to ethanol-mediated oxidative stress, and up-regulated the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream anti-oxidant protein heme oxygenase-1 (HO-1) in ethanol-treated mice. In acute ethanol-induced liver injury model, PCP decreased the elevation of MDA level, restored GSH level and enhanced the activities of SOD and catalase (CAT) in both serum and liver, which was associated with the inhibition of hepatic CYP2E1. Additionally, alcohol exposure markedly induced the lipolysis of white adipose tissue (WAT) through up-regulating protein expression of adipose triglyceride lipase (ATGL) and phosphorylation of hormone-sensitive lipase (p-HSL), and enhanced fatty acid uptake capacity in liver by elevated hepatic CD36 expression, which attenuated by PCP treatment. Taken together, our data demonstrated that treatment of PCP protected against chronic and acute ethanol-induced liver injury, possibly through reducing CYP2E1- dependent oxidative stress and ameliorating dysfunctional WAT derived-fatty acids influx to the liver. Our findings also suggested that PCP might be a promising agent for the prevention of alcoholic liver disease.
Chinese Abstract
酒精的長期和過量攝入會造成肝臟的損害性病變,當肝細胞內的脂質堆積超過 肝臟濕重的 5%時,可定義為脂肪肝。在世界範圍內,酒精性脂肪肝的發病率呈 逐年上升的趨勢,由其引起的肝臟炎症,肝硬化和肝癌已經嚴重危害了人體的生 理健康。到目前為止,還沒有 FDA 批准上市的藥物可用於治療酒精性脂肪肝。 中醫藥對肝臟的保益作用一直被大家所關注,諸如解酒保肝湯,加味溫膽湯等中 藥方劑均表現出良好的保肝作用。該論文研究所涉及的趕黃草,原是中國古蘭苗 族地區用來泡茶醒酒的一味中草藥。由於近年來,研究者通過實驗調查發現其顯 著的保肝退膽作用,已漸漸成為治療肝病的一種潛在可開發藥物,而其對酒精性 脂肪肝的作用及內在機理還未有深入的報道。 目的:研究趕黃草水提物對小鼠急性和慢性酒精性脂肪肝的保護作用并通過 脂肪-肝臟軸,氧化應激和炎性通路等多方面探究其產生作用的內在機制。 方法:建立小鼠酒精性脂肪肝體內模型。急性造模採用 4.7g/kg BW 乙醇, 間隔 12h 灌胃,給藥組于造模前進行連續 7 天的灌胃給藥,對照組同時灌胃超純 水;慢性造模採用經典的 Lieber-DeCarli 液體飼料飼餵 4 周,藥物于飼料中同時 給予。給藥劑量均為兩組(5.3g/kg,10.3g/kg),按不同模型分別給藥。于造模給 藥結束后,麻醉小鼠,取血漿和肝臟保存于-80°C 待測。通過油紅染色觀察肝 細胞內脂質堆積情況。常規測定血漿生化學指標丙氨酸氨基轉移酶、天門冬氨酸 氨基轉移酶、血脂四項,用酶聯免疫法測定肝臟內 TNF-a, IL-6 的含量。最後運 用免疫印跡和定量 PCR 測定相關蛋白和 mRNA 的表達情況。 結果:實驗成功的複製了小鼠急慢性酒精性脂肪肝的體內模型。結果顯示, 趕黃草水提物對小鼠急性或慢性酒精性脂肪肝均有一定的保護作用。具體表現為, 給藥組小鼠肝臟內的脂滴堆積減少,脂滴體積變小,血漿 ALT,AST 均較模型組 顯著下降,肝臟內 TG 含量下調,肝內炎性因子 TNF-a,IL-6 下降,相關氧化抗 氧化酶和非酶系統(MDA, SOD, GSH, GPx, ROS)均有不同程度的改善; 線粒體 內肝藥酶 CYP2E1 在蛋白和 mRNA 的表達上較模型組均有顯著性的下降。在急 性模型中,幫助脂解的蛋白 p-HSL 和 ATGL 在攝入酒精后,均表達上調,PCP 能降低由酒精引起的脂解相關蛋白上調,并使肝臟內攝入游離脂肪酸的載體蛋白 CD36 表達減少,減少游離脂肪酸攝入,減低血中和脂肪組織釋放的 FFA 含量;在慢性模型中,PCP 增加了 Nrf2 和其下游 HO-1 的表達,激活了抗氧化通路。 結論:趕黃草水提物對小鼠急性和慢性脂肪肝均有一定的保護作用,其產生 保護作用的機理有所側重。慢性模型中,PCP 顯示出良好的抗氧化作用,通過激 活氧化應激,產生對肝細胞的保護作用,防止肝細胞的進一步損傷;在急性模型 中,PCP 能改善由酒精引起的脂解增加,防止游離脂肪酸向肝臟的流動,減少肝 臟對 FFA 的吸收,通過減少脂質堆積,維持肝細胞的正常功能。急性模型中, PCP 也顯示出了良好的抗氧化作用。不論急性還是慢性模型,PCP 均顯示出了對 有關炎性的指標的改善作用。總結說明 PCP 通過各通路相互協調,共同改善了 酒精性脂肪肝的脂質堆積和肝細胞受損程度,為未來的新藥開發,提供了一定的 嚮導作用。 關鍵字:酒精性脂肪肝;趕黃草水提物;氧化應激;肝臟-脂肪軸;抗炎
Issue Date
2015
Author
Cao, Yi Wei
Faculty
Institute of Chinese Medical Sciences
Degree
M.Sc.
Subject
Alcoholic liver diseases -- Prevention
Medicinal plants -- China
Materia medica -- China
Chinese Medicinal Science -- Institute of Chinese Medical Sciences
中藥學 -- 中華醫藥研究院
Supervisor
萬建波
Library URL
b3507929
Files In This Item:
Full-text (Intranet only)
Location
1/F Zone C
Supervisor
--