上皮生長因子改善腸道通透率對於大白鼠酒精性肝臟疾病之影響

Effects of epidermal growth factor on alcoholic liver disease in rats by improving intestinal permeability

謝伊晴(Yi-Ching Hsieh)

指導教授 ： 楊素卿

臺北醫學大學/公共衛生暨營養學院/保健營養學研究所/碩士(2010年)

https://doi.org/10.6831/TMU.2010.00127

摘要

近幾年對於酒精性肝臟疾病 (alcoholic liver disease, ALD) 之研究焦點逐漸重視腸道之完整性，長期攝取酒精可能藉由破壞腸道完整性及影響腸道菌叢生態，而使源自腸道之細菌內毒素 (endotoxin) 進入血液中，進一步惡化ALD之病程。研究指出上皮生長因子 (epidermal growth factor, EGF) 具有促進腸胃道上皮細胞生長及分化之功能，因此，本研究針對腸道完整性及腸道菌相變化兩方面，探討EGF之補充是否具有改善大白鼠酒精性肝臟疾病之作用及其可能機制。8週齡雄性Wistar大白鼠40隻經一週適應期後，先依照血液肝功能指數天門冬胺酸轉胺酶 (aspartate aminotransferase, AST) 與丙胺酸轉胺酶 (alanine aminotransferase, ALT) 活性將所有大鼠分成兩組，分別以正常液體飼料 (以麥芽糊精取代酒精) 及酒精液體飼料 (酒精占總熱量之35%)，飼養4週後，以有無添加EGF再各別分成兩組，包括正常液體飼料組 (C)、正常液體飼料並補充EGF組 (C+EGF)、酒精液體飼料組 (E) 及酒精液體飼料並補充EGF組 (E+EGF)，共四組。EGF (30 μg/kg/day) 直接添加至液體飼料中給予動物自由進食，並持續8週。於酒精誘導期第0、4週以及EGF介入期第4週進行尾靜脈採血，12週後進行大白鼠腸道通透性 (intestinal permeability) 試驗及糞便菌相培養，同時將動物進行犧牲以收集腹大動脈血液、肝臟及小腸樣本進行分析。實驗結果顯示，酒精組大白鼠血漿中AST與ALT活性顯著上升，且肝臟組織切片判讀評分結果發現酒精組脂肪變性 (fatty change) 評分顯著較高且發炎情形評分亦顯著較高，並可觀察到肝臟中三酸甘油酯 (triglycerides, TG) 濃度有顯著增加之現象，另外，肝臟中腫瘤壞死因子 (tumor necrosis factor-α, TNF-α)、介白素-1β (interlukine, IL-1β) 及介白素- 6 (interlukine-6, IL-6) 等促發炎細胞激素濃度亦顯著增加，而腸道完整性方面，結果顯示酒精組大白鼠之小腸黏膜總DNA含量顯著降低及小腸黏膜EGF濃度顯著增加，顯示長期攝取酒精可能導致小腸黏膜損傷，且結果發現大白鼠之腸道通透性有增加之趨勢，另一方面，糞便中大腸桿菌 (E. coli.) 菌落數有增加之趨勢而乳酸桿菌 (Lactobacillus) 菌落數則顯著減少，並且發現血漿內毒素濃度有明顯增加。EGF補充8週後，可顯著抑制血漿中AST與ALT活性上升及抑制肝臟TNF-α、IL-1β及IL-6等促發炎細胞激素濃度顯著增加，腸道完整性方面，EGF補充可使大白鼠小腸黏膜EGF濃度正常化以及顯著降低腸道通透性，另一方面，可減少糞便中E. coli菌落數及總厭氧數，因此可改善長期攝取酒精導致之內毒素血症，進一步改善肝臟之發炎反應。故補充EGF可以藉由維持腸道完整性及改變糞便中腸道菌相平衡之作用，改善大白鼠內毒素血症而降低肝臟發炎反應，而進一步達到改善大白鼠酒精性肝臟疾病之效果。

關鍵字

上皮生長因子 ； 酒精性肝臟疾病 ； 腸道通透性

並列摘要

Clinical and animal data indicate that gut-derived endotoxin and gut microbiota contribute to the pathogenesis of alcoholic liver disease (ALD). The aim of this study was to investigate whether epidermal growth factor (EGF) supplementation can improve ALD in rats by influence of intestinal integrity and gut microbiota. The 8-week-old male Sprague-Dawley rats were acclimated for 1 week, and then according to plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities, 40 rats divided into two groups (n=20 per group) for feeding a normal liquid diet (C group) or a diet containing 5% ethanol (E group). After a 4-week ethanol-induced period, both C group and E group were subdivided into two groups respectively, such as normal liquid diet without or with EGF supplement (C group, n=10; C+EGF, n=10) and a ethanol-containing diet without or with EGF supplement (E group, n=10; E+EGF group, n=10). EGF (30 μg/kg/day) intervention period were carry out for 8 weeks. At week 0 and 4 of ethanol-induced period and week 4 of EGF intervention period, blood sample was collected via the tail vein. After 12 weeks, all rats were proceeded intestinal permeability test and microbial culture of feces. Then, all rats were sacrificed and blood, liver, and small intestine were collected for analysis. Our results show that alcohol contributes to increased gut permeability, plasma AST, ALT activities and endotoxin level, as well as hepatic TNF-α, IL-1β, and IL-6, and decreased the numbers of fecal Lactobacillus. EGF supplementation effectively attenuated the alcohol?{induced endotoxemia and the increase in plasma AST and ALT activites, hepatic TNF-α, IL-1β, and IL-6 levels. EGF supplementation protected against alcohol?{induced hyperpermeability of intestine, and increase of fecal E. coli bacteria counts. In conclusion, this study demonstrates that EGF possesses a novel hepatoprotective function in ALD by improving alcohol-related changes in the gut-liver axis.

並列關鍵字

epidermal growth factor ； alcoholic liver disease ； intestinal permeability

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