2014-08-012024-05-13https://scholars.lib.ntu.edu.tw/handle/123456789/644142摘要：膽汁滯留性肝臟疾病是先天性或後天性肝臟疾病最重要-的表現之一，慢 性膽汁滯留會造成致命性的肝硬化及肝衰竭，此外膽汁滯留性肝臟疾病亦是兒童 肝臟移植的首要病因。膽汁滯留性肝臟疾病最大的影響，就是肝臟最重要的生理 功能─膽汁分泌及膽汁流通,發生障礙。由於膽汁的主要功能是在腸道內幫助消 化脂肪及脂溶性維生素的吸受，因此膽汁滯留時，會造成脂肪及脂溶性維生素 (A,D,E,K)的缺乏疾病，進而造成生長不良及多重器官功能障礙。這包括凝血功 能異常、軟骨症、神經及視力功能受損。此外，體內維生素 A 及 E 濃度低下， 也影響肝臟抗氧化之作用，加重膽汁滯留肝傷害的程度。抗氧化劑在近年被認為在治療肝臟疾病方面有不錯的效果，其作用機制正 被廣泛積極研究中。維生素 E 用於非酒精性脂肪性肝炎已被證實具有療效，而 其在膽汁滯留的療效及機轉仍不清楚；值得注意的是，在我們的臨床研究中，發 現慢性膽汁滯留病人，雖接受固定維生素補充，然維生素 A 及 E 缺乏比率仍達 70% 及 90%以上，此問題過去一直被忽視。在過去研究中,我們建立了大鼠肝細 胞培養系統，及其膽酸傷害模式，此系統可測試篩選可能具治療功能的藥物; 我 們發現 beta-carotene 及 tocopherol 有利於肝細胞型態、存活及生長，並且beta-carotene 可能有促進膽小管傳送蛋白之表現之功能，此兩種藥物可能對於膽 汁滯留肝臟疾病有治療的潛力。本研究將利用動物實驗,進一步證實 beta-carotene 及 tocopherol，其在活體 治療膽汁滯留的效果，我們將利用總膽管結紮大鼠作為阻塞性膽汁滯留的疾病治 療模式，分析其血清膽汁酸及脂肪濃度、肝功能指標、血漿 beta-carotene 及 tocopherol 濃度、肝臟病理變化，並著重分析肝細胞膜傳送蛋白之表現變化，比 較給予大鼠藥物治療後其膽汁滯留肝傷害改善情形。若此藥物可促進肝細胞膜傳 送蛋白之表現及定位，則不但可改善膽汁治流引起之肝傷害，並可促進膽汁排 出，減低肝臟膽汁的負擔，能更有效的治療膽汁滯留. 第三年我們將篩選治療效 果良好的其中一種藥物，進行機轉探討，我們將分析其使用藥物前後，肝臟核受 體 FXR,PXR 調控之基因變化(包括 CYP7A1,SHP,BSEP,OATP2 等)，並利用 FXR 拮抗劑 guggulsterone (GGS) ，探討 beta-carotene 或 tocopherol 對於膽汁排出的作<br> Abstract: Cholestatic liver disease is one of the most common form of liver disorders resulted from inherited or acquired liver diseases. Chronic cholestatic liver disease may progress to liver cirrhosis and liver failure, and is the leading cause for pediatric liver transplantation. In cholestatic liver diseases, an important physiological function,i.e. bile secretion is impaired, which results in of defective absorption for fat andfat-soluble vitamins (vitamins A,D,E, and K). Deficiency in fat-soluble vitamins may result in multiple organ dysfunctions, including rickets, coagulopathy, and defective neurological and visual function. In addition, low levels of Vitamin A and E also attenuate the antioxidant activity in the body, and may aggravate the cholestatic liver injury.Anti-oxidant therapy has been found to be promising in treatment various liver diseases. Vitamin E has been used to treat nonalcoholic steatohepatitis. However, the effects of fat-soluble vitamins in ameliorating liver injuries in cholestatic liver diseases have not been well investigated. Of note is that from our clinical study, a strikingly high prevalence of Vitamin A and E deficiency was noted: 70% and 90% despite the patients have been regularly followed-up. It is important that deficiency in fat-soluble vitamins is been overlooked. In our previous study, we have used primary rat hepatocyte culture system to screen some candidate drugs for cholestatic injury.We found that beta-carotene and tocopherol were effective for hepatocyte survival and growth. Beta-carotene were found to enhance the expression for canalicular proteins.In the present study, we will investigate the therapeutic effects ofbeta-carotene and tocopherol in experimental animal models of cholestasis. In experimental animal model using common bile duct ligated rats, we will analyze the changes of plasma biochemistry, plasma levels of fat-soluble vitamins, liver histology, and focusing on the changes of expression of canalicular transporters and nuclear receptors. We will investigate whether administration of beta-carotene and tocopherol may attenuate the cholestatic liver injuries, and also investigate mechanisms of their therapeutic effects in relation to bile metabolism and excretion.The present study is important to clarify the dual therapeutic effects of fat-soluble vitamins, not only for correcting the nutritional defects but also foranti-oxidant and choleresis effects. The mechanisms of preventing liver injuries in cholestasis and therapeutic targets through changes of heptocyte transporters andnuclear receptors are also to be analyzed. The results will have great potential in clinical applications in human patients with cholestatic liver diseases and will benefit cholestatic patients in the near future.