Visfatin在非酒精性脂肪性肝病发展过程中的表达及意义

观察血清及肝脏组织中内脂素(Visfatin)的表达情况,探讨其在非酒精性脂肪性肝病(nonalcoholic fattyliver disease,NAFLD)发生、发展过程中的作用.以高脂饮食构建NAFLD大鼠模型,应用酶联免疫吸附法、RT-PCR及免疫组织化学等方法,动态检测大鼠NAFLD发展过程中血清Visfatin的含量及其在肝组织中的表达.结果显示:在模型组大鼠由单纯性脂肪肝(SS)发展为非酒精性脂肪性肝炎(NASH)的过程中,Visfatin在大鼠血清和肝组织中的表达均呈现由高到低的变化趋势,SS组大鼠Visfatin的表达显著高于正常对照组和NASH组(P<0.01),而正常对照组和NASH组之间无明显差异;SS组大鼠Visfatin主要表达于小叶中央静脉周围脂肪变性相对较轻的肝细胞内.由此认为,Visfatin在血清和肝组织中的高表达作为早期事件,可能在NAFLD发展过程中起重要作用.     

非酒精性脂肪性肝病大鼠肝脏PPAR-γ的表达

目的：研究PPAR-γ在非酒精性脂肪性肝病（NAFLD）大鼠肝脏组织中的表达,探讨非酒精脂肪性肝病可能的发病机制。方法：雄性SD大鼠30只,随机分为A（正常组）15只普通饮食,B（高脂组）15只高脂饮食。8周后,自两组各随机抽取2只大鼠处死,光镜观察证实脂肪肝造模成功,继续喂养4周后处死所有大鼠,取血清做免疫生化检查,取肝组织标本,分别以光镜观察做出NAS评分,免疫组化和PCR法检测肝组织PPAR-γ蛋白的表达。结果：1.高脂饮食可以成功的复制NAFLD的大鼠模型;2.血清GLU、TC、TG、HDL-C、LDL-C在高脂组表达量较正常组明显升高,差异具有统计学意义（P〈0.05）;3.免疫组化显示：高脂组PPAR-γ表达量较正常组升高;结论：1.高脂饮食可成功复制NAFLD模型;2.PPAR-γ在NAFLD大鼠肝脏成脂性改变中具有重要作用。     

非酒精性脂肪性肝病大鼠肝脏PPAR-γ的表达

目的:研究PPAR-Y在非酒精性脂肪性肝病(NAFLD)大鼠肝脏组织中的表达,探讨非酒精脂肪性肝病可能的发病机制.方法:雄性SD大鼠30只,随机分为A(正常组)15只普通饮食,B(高脂组)15只高脂饮食.8周后,自两组各随机抽取2只大鼠处死,光镜观察证实脂肪肝造模成功,继续喂养4周后处死所有大鼠,取血清做免疫生化检查,取肝组织标本,分别以光镜观察做出NAS评分,免疫组化和PCR法检测肝组织PPAR-Y蛋白的表达.结果:1.高脂饮食可以成功的复制NAFLD的大鼠模型;2.血清GLU、TC、TG、HDL-C、LDLC在高脂组表达量较正常组明显升高,差异具有统计学意义(P＜0.05);3.免疫组化显示:高脂组PPAR-Y表达量较正常组升高;结论:1.高脂饮食可成功复制NAFLD模型;2.PPAR-Y在NAFLD大鼠肝脏成脂性改变中具有重要作用.     

非酒精性脂肪肝病肝组织超微结构特点

目的:阐明非酒精性脂肪肝病(NAFLD)的超微结构特点。方法:收集我校和其他单位送检的3例单纯性非酒精性脂肪肝,16例NASH患者和4例NAFLD肝硬化患者的肝穿刺组织。用2.5%戊二醛、1%锇酸双固定、Epon 812包埋,超薄切片70nm,醋酸铀和柠檬酸铅染色后,JEM-2000EX透射电镜观察。结果:单纯性脂肪肝患者主要表现为大小不等的脂滴沉积、以小脂滴为主,可互相融合。NASH患者的肝细胞都可出现大量脂滴积聚,为大小脂滴混合型、内容物主要为中等电子密度、比较均一的甘油三酯,部分脂滴周围可见磷脂成分,NASH患者肝细胞内脂滴也互相融合。肝细胞线粒体的超微结构改变包括多形性线粒体、基质颗粒增多、线粒体增大和嵴的丧失是主要的电镜异常发现,线粒体内还可见副晶格样包涵体。部分NASH患者肝细胞内可见Mallory小体。NASH患者肝细胞周围可见淋巴细胞浸润。肝血窦Kupffer细胞增生不明显,NAFLD肝硬化患者Disse间隙和肝细胞间可见胶原纤维增生。结论:NAFLD具有较为明确的超微结构改变,电镜检查有助于诊断。     

非酒精性脂肪肝大鼠PPARα基因表达及脂代谢和胰岛素水平的变化

目的观察非酒精性脂肪肝（NAFLD）大鼠肝组织中PPARα基因的表达,并用PPARct激动剂进行干预,探讨其与胰岛素抵抗、脂代谢紊乱的关系。方法大鼠随机分为①正常对照组、②高脂模型组、③PPARα激动剂干预组,利用高脂饮食建立大鼠非酒精性脂肪肝模型。12周后,检测大鼠血脂、肝功能、血糖、胰岛素水平及胰岛素抵抗指数;RT-PCR法分析PPARα基因的表达;观察肝脏的形态学改变。结果PPARa激动剂可降低NAFLD大鼠转氨酶、血脂水平及胰岛素抵抗指数,可促进NAFLD大鼠中PPARa基因的表达;肝脏形态学明显改善。结论PPARα激动剂能改善NAFLD大鼠脂质代谢紊乱,有明显的保肝降酶作用,具有适度的胰岛素增敏作用。PPARα及其配体在NAFLD发病机制及治疗中的进一步深入研究,将为临床防治NAFLD提供新的思路。     

miRNA在非酒精性脂肪肝病中的作用研究进展

非酒精性脂肪性肝病(nonalcoholic fatty liver disease, NAFLD)是目前临床常见的肝病之一,随着生活水平的提高,NAFLD的发病率不断升高,严重威胁了人们的健康,其发病机制尚未完全阐明。微小RNA(microRNA, miRNA)是一类广泛存在的非编码分子RNA,通过转录后水平调节基因的表达参与调控一系列的生命活动。近年来越来越多的研究发现,miRNA通过各种途径在NAFLD的发生发展中起着关键作用。本文主要对近年来miRNA在非酒精性脂肪肝病中的机制研究进展进行简单综述。     

Nrf2及其相关因子在非酒精性脂肪肝炎形成过程中的作用

目的：通过观察大鼠非酒精性脂肪肝炎（NASH）形成过程中脂质代谢、肝组织病理学改变、核因子E2相关因子2（Nrf2）及相关键因子的转录和蛋白水平的变化,探讨Nrf2及其相关因子在NASH形成过程中的作用。方法：sD大鼠分为正常组和模型组,以饲喂高脂饲料建立非酒精性脂肪肝炎模型,分别于4、12周末处死,检测血清和肝组织中谷丙转氨酶（ALT）、谷草转氨酶（AST）、总胆固醇（TC）、甘油三酯（TG）、高密度脂蛋白胆固醇（HDL-C）、低密度脂蛋白胆固醇（LDL-C）含量;油红O染色法检测肝组织内脂肪沉积变化,常规HE染色观察肝组织病理学改变,计算NAFLD活动度积分（NAS）,免疫组化检测肝组织Nrf2表达;Real-time PCR和Westernblot技术检测肝组织Nrf2及其相关因子mRNA和蛋白表达水平。结果：①4周模型组大鼠血清ALT、AST、TC和肝组织TC、TG、LDL-C等指标较同期正常组均显著增高（P〈0．01,P〈0．05）,12周模型组大鼠血清、肝组织脂质含量持续增高（P〈0．01,P〈0．05）,肝组织HDL-C较正常组显著降低（P〈0．05）,比4周变化明显。②4周和12周模型组大鼠肝细胞内沉积大量脂肪滴,肝细胞脂肪变严重,伴有肝细胞气球样变;且随着高脂饮食喂养时间的延长,肝组织内脂肪沉积以及肝细胞脂肪变程度明显加重,NAFLD评分、Nrf2表达强度均显著增高（P〈0．01）。③4周、12周模型组大鼠Nrf2、H01、NQOt、rGCS、GST的mRNA和蛋白表达均有不同程度的上调或抑制,且12周比4周变化明显（P〈0．01,P〈0．05）。结论：Nrf2及相关因子可能参与了非酒精性脂肪性肝病的发生发展过程,在NASH形成过程中起着重要的作用。     

焦磷酸测序法检测OCT4启动子在大鼠骨髓源性肝干细胞分化中的甲基化变化

骨髓间充质干细胞具有分化成为肝细胞的潜能已得到证实,但其分化的调控机理还不完全清楚。通过检测大鼠骨髓源性肝干细胞(rat bone marrow-derived liver stem cells,RBMLSCs)诱导分化为肝细胞过程中OCT4启动子甲基化的变化,来探讨启动子甲基化调控细胞分化的机制。RBMLSCs用25μg/L重组人肝细胞生长因子和0.1 nmol/L地塞米松进行诱导,在诱导之后不同时间点(0 d,7 d,14 d)提取细胞的DNA及RNA。用荧光定量PCR法检测白蛋白(albumin,Alb)和OCT4的m RNA表达水平,应用焦磷酸测序法定量检测OCT4基因的启动子中4个Cp G位点的甲基化变化。结果表明:在RBMLSCs分化过程中,Alb m RNA持续增高(P0.05),但OCT4 m RNA表达在7 d及14 d明显减少(P0.005);同时OCT4启动子上游的Cp G 1-2-3甲基化频率显著上升(P0.001),但Cp G 4甲基化无明显变化。这些结果说明OCT4启动子高甲基化可能导致其m RNA表达减少,RBMLSCs多能性消失,但Cp G 4并不参与这一分化调控过程。     

KLF9通过上调CD36调节肝脏脂代谢

非酒精性脂肪性肝病(nonalcoholic fatty liver disease, NAFLD)的发生和发展与脂肪酸的摄取密切相关。本研究旨在探索Krüppel样转录因子9 (Krüppel-like factor 9, KLF9)对脂肪酸转位酶CD36、肝细胞的脂代谢以及非酒精性脂肪肝的发生和发展所产生的影响。采用高脂饮食构建的高脂模型C57BL/6J小鼠和db/db糖尿病小鼠,检测其肝脏内Klf9和Cd36基因和蛋白表达水平的变化。分离C57BL/6J小鼠原代肝细胞进行体外培养,分别给予Ad-GFP、Ad-Klf9、Ad-shCtrl或Ad-shKlf9处理,然后利用油酸和棕榈酸进行24 h的诱导;同时构建肝脏特异性Klf9基因敲除小鼠,采用Western blot检测KLF9蛋白表达水平的变化,real-time PCR检测Klf9和Cd36 mRNA表达水平的变化,试剂盒测定甘油三酯含量的变化,油红O染色检测脂质含量的变化。结果显示:(1)与对照组相比,高脂饮食诱导的肥胖小鼠或db/db糖尿病小鼠肝脏Klf9的表达显著增加;(2)在小鼠原代肝脏细胞中过量表达Klf9会增加Cd36表达水平,导致细胞脂肪含量增加;(3)相反,在小鼠原代肝脏细胞中敲低Klf9的表达则降低Cd36表达水平,从而减少肝细胞脂肪含量;(4)小鼠肝脏Klf9敲除能降低肝脏Cd36表达,改善高脂饮食诱导的脂肪肝表型。上述结果表明,肝脏KLF9通过促进CD36的表达影响肝脏的脂代谢。     

非酒精性脂肪肝大鼠脂质代谢及病理变化的动态观察

目的通过高脂饮食建立NAFLD大鼠模型,连续监测4～16周模型动物肝功能、脂质代谢、胰岛素抵抗及肝细胞凋亡在NAFLD进展过程中的变化情况及相互关系,为该模型在脂肪肝发病机制、脂肪肝治疗药物评价等方面的应用提供参考依据。方法 SD大鼠50只,除正常对照组外,其余动物饲喂高脂饲料,分别检测4,8,12,16周大鼠血清GLU、CHO、TG、HDL、LDL、GPT、GOT及胰岛素水平,肝脏组织切片进行病理学及细胞凋亡观察,进一步分析大鼠肝功能、脂质代谢、胰岛素抵抗及肝细胞凋亡对肝组织病理改变的影响。结果模型组大鼠4周后就出现肝功能损伤,脂质代谢紊乱、胰岛素抵抗,肝细胞凋亡8 W后明显增加,肝细胞脂变及炎症为肝组织病理变化的主要特征,且造模时间越长,病变程度越严重。结论经过高脂饲料的喂养,SD大鼠在4～16周内可形成病变程度逐步加重的NAFLD模型,肝功能损伤,脂质代谢紊乱及肝细胞凋亡是引起非酒精性脂肪肝中脂肪变性和炎症的重要因素,该模型可应用于脂肪肝治疗药物评价等方面。     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various