【作者】 张昭萍；

【导师】 王瑞云； 戚晓红；

【作者基本信息】 南京医科大学 ， 感染病学， 2001， 硕士

【摘要】 脂肪肝主要是由于肝脏摄入、合成脂肪与其分泌、氧化分解之间失衡 引起中性脂肪（主要为甘油三酯）在肝内积聚所致。目前，国内外尚无理想的针对脂肪肝的特效治疗药物。甲壳素（chitin），是从动物甲壳中提取的一类线性高分子多糖，其脱乙酰化产物—壳聚糖具有多种药理作用，动物实验表明壳聚糖能有效地降低血胆固醇。此外，许多中药如何首乌、丹参、牛膝、泽泻等亦均有良好的降脂作用。我们在以前的研究中，用壳聚糖合并中药何首乌、丹参、牛膝预防大鼠脂肪肝取得了一定的效果，但其治疗作用如何尚未探讨，且预防组大鼠肝脂质含量与正常组相比有一定的差异。据文献报道中药决明子和泽泻有明显的降脂作用，故我们设想在原药的基础上添加决明子和泽泻，可能在治疗实验中会起到更好的治疗脂肪肝的作用。本实验通过建立大鼠脂肪肝模型，研究了原药（治疗药物1）及在其基础上添加决明子和泽泻后的药物（治疗药物2）对脂肪肝的治疗作用及其机理，以筛选更有效的治疗脂肪肝的药物，为临床治疗脂肪肝提供理论依据。 本实验在小剂量四氯化碳致肝损伤基础上合并高脂饮食建立大鼠脂肪肝模型，分别给予治疗药物1和治疗药物2进行治疗实验，结果发现四氯化碳合并高脂饮食可引起大鼠肝脏明显的脂肪变性，表现为肝组织TG、TC含量显著增加，并伴有血清ALT活性增高。病理切片检查显示：肝细胞肿胀，内部充满大小不等的脂滴，而药物治疗组大鼠肝脏TG、TC值均明显降低，以治疗组2下降最明显。光镜下药物治疗组肝细胞脂变程度明显减轻，表现为脂滴减少，脂变面积缩小，尤以治疗组2脂变程度最轻，已基本接近于正常水平。另外，治疗药物2还可使大鼠血清ALT活性明显降低，说明其具有一定的 南京医科大学硕十学位论文 保肝作用。结跪明治疗药物1和2哪8栅均有明显治疗作用，而 治疗药物二的治疗滁锄明显。 过剥匕物酶体增殖物激活受体（PPARs）是一类s敝…物 酶体增鞭H8顺，贝特类酬旨药）腑的核内弧，翩内激 素受体超账。自1990年由Issmann拄J见以来，国夕呐绷十分 WM的研究铡，其亚型PPARaM内龈代谢动妒铡 拗中走星霎卧作用。目前普遍认为，脂凡m汗患酮源。防内毒素血巧良 发病锨高，内跪（ET）可引起肿瘤坏死因子。（TN’F。）a 谢。，而鞭的腑表明TNFa可引娜内PPARamRNA衅及 蛋白衅的下降，濒TNF a可能通旬减少PPAR anlltNHM引 栅内脂质…L，从而邮girl：’w＂’＝ 中卿用。止时，游离脂 赔（FFA）在脂腑的发病邮仲 占重要地位，而脂瞅时FFA 增加与PPAR。系杉邓H贿关。因此，本研究还应用半定量逆转录一 聚合哟韩色良应（m－Pm）法观察了壳聚糖合并中药对大脐—— a mRNAmRNA铀的影响，并测定了大鼠血清ET、TTNF、FTA发J刊庄FFA 的变化，以过卜一步从J卜于水刁o开究其发挥治疗作用的邮0。结贩明， 脂 组大肌PPARa铀明显减少；娠ET、M、FFA 含量和肝FFA衅均明显增力民经药物治疗后肝PPARa 焕 肚常郴，娠ET、TN’F、FFA含量和肝FFA材均明显均下民 综上所述，壳聚糖合并中药可明显咧氏实验哪8栅大鼠扦脏 脂质飨，减洲8变程度 刷B蝴明显治疗作用。其治疗衅 可能除了减少肠铡旨肪的测妙，助能与贩PPARa协减 轻ET、TNF、FFA毒断用有关。更多还原

【Abstract】 Fatty liver, or hepatic steatosis, may occur in a variety of situations in which lipid uptake or synthesis overwhelms the capacity of the liver to oxidate and secrete them, leading to their accumulation. Triglyceride is the main lipid found in most cases of fatty livers. Chitin, a kind of linear macromolecular aminopolysaccharide prepared from the exoskeletons of crabs and shrimps, has many pharmacological effects. Previous studies have indicated that chitosan, the partly deacetylated derivative of chitin, can prevent the experimental hypercholesterolemia of rat. In addition, traditional Chinese medicines such as Polygonum multifiorum Thumb.,Salvia miltiorrhiza Bge., and Achyranthes bidentata BL. have satisfactoiy effect on treating fatty liver. Our previous study identified that cbitosan and traditional Chinese medicines including Polygonum multiflorum Thumb.,Salvia miltionhiza Bge. and Achyranthes bidentata BL.(drug 1) had a remarkable effect on preventing fatty liver, but its effect on treating fatty liver had not been studied yet . It was reported that Cassia obtasifolia L. and Alisma plantago L. had favorable effect on reducing liver lipid accumulation. So Cassia obtasifolia L. and Alisma plantago L. were added to the above-mentioned drug (drug 2) to strengthen its function of inhibiting the lipid deposition in liver. In this study, we investigated the effect and mechanism of drug 1 and drug 2 on rat fatty liver in order to search for a drug treating fatty liver effectively. Male Rats were treated with a low dose of carbon tetrachloride (CC14) and fed a high fat diet to produce fatty liver. Then, the therapeutic groups were treated with drug 1 and drug 2. The concentrations of triglyceride (TG), total cholesterol (TC) and alanine aminotransferase (ALT) were detected and the mohology changes of hepatocyte were evaluated to assess the therapeutic effect The results demonstrated that the combining use of CCLI and high-fat diet induced the contents of TG, TC in liver to increase significantly. Pathological examinations showed that swelling hepatocytes were filled with lipid droplets in model group while the treated group displayed a slight seeatosis and a lower TG, TC contents compared with the model group. Among the treated group the effect of drug 2 was more effective. Moreover, drug 2 also made the ALT activity decrease. Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear steroid hormone receptor superfamily activated by structurally diverse chemicals referred to as peroxisome proliferators such as fatty acids and fibrate lipid-lowering drugs. Studies over the past few years have shown that the a -isoform of the receptors , PPAR a, is a key regulator of lipid homeostasis. It is established that tumor necrosis factor (TNF) and free fatty acids (FFAs) play a pivotal role in the pathogenesis of fatty liver. Studies recently identified that the mRNA for PPAR a was significantly reduced by TNF a treatment. In addition, the level of PPAR a protein was also decreased after TNF a treatment. This effect may have important implications in perturbation of the lipid metabolism induced by TNTF a. Studies also found that deletion of PPAR a gene leads to a remarkable decrease in FFAs uptake. Consequently, we hypothesize that PPAR a involves in the pathogenesis of fatty liver. To explore the molecular mechanism of chitosan and traditional Chinese medicines in treating fatty liver, hepatocyte PPAR a expression was analyzed and the concentrations更多还原