基于AMPK/SREBP-1通路研究狗肝菜多糖对高脂饮食大鼠糖脂代谢的影响

本研究探讨狗肝菜多糖(DCP)对高脂饮食大鼠糖脂代谢的作用及机制。实验采用高脂饲料喂养8周,将造模成功的40只大鼠随机均分为正常组、模型组、DCP剂量组(100、200 mg/kg),每组10只;从第9周开始,DCP剂量组灌胃给药,正常组和模型组给予等体积蒸馏水灌胃,持续6周,处死,收集血样和肝脏。采用生化法检测血清中甘油三酯(TG)、总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)、游离脂肪酸(FFA)、糖基化终产物-肽(AGE-P)和糖化血红蛋白(HbA1c)含量,及肝脏中TG和肝糖原含量;葡萄糖氧化酶法测定空腹血糖(FBG),酶联免疫吸附试验(ELISA)检测血清空腹胰岛素(FINS)含量,计算胰岛素抵抗指数(HOMA-IR);油红O染色观察肝组织脂肪沉积状况;蛋白免疫印迹实验(Western blot)检测大鼠肝组织中胆固醇调节元件结合蛋白1(SREBP-1)、腺苷酸激活蛋白激酶(AMPK)和磷酸化腺苷酸活化蛋白激酶(p-AMPK)蛋白表达情况;实时荧光定量PCR(RT-PCR)检测SREBP-1 mRNA、AMPK mRNA水平。结果显示,DCP(100和200 mg/kg)剂量组能显著下调TC、TG、LDL-C、FBG、FINS、AGE-P和HbA1c含量和HOMA-IR,上调HDL-C和肝糖原含量,减少脂肪沉积物,同时明显上调p-AMPK水平,抑制肝组织SREBP-1蛋白及其mRNA的表达。结果表明,DCP调节大鼠糖脂代谢的机制可能与调控AMPK/SREBP-1通路有关。     

肥胖大鼠模型的建立及其脂代谢相关分子机制研究

目的建立饮食诱导的肥胖(diet-induced obesity,DIO)大鼠模型并初步探讨其发病的分子机制。方法用脂肪含量30%的高脂饲料饲喂雄性SD大鼠25周,观察大鼠体重、Lee’s指数、肝组织病理改变,检测大鼠空腹血糖及空腹血清胰岛素水平,并通过real-time PCR,检测成模大鼠肝脏中乙酰辅酶A羧化酶(ACC)、脂肪酸合酶(FAS)、激素敏感酯酶(HSL)以及固醇调节元件结合蛋白-1c(SREBP-1c)的表达变化。结果高脂饲料饲喂6周后,DIO组大鼠体重、Lee’s指数均显著增加;25周后肝脏脂肪异常蓄积,出现中重度脂肪肝,空腹血糖及胰岛素水平显著升高,出现明显的胰岛素抵抗。肝脏中ACC、FAS和HSL表达显著增加,SREBP-1c表达水平达到正常组的2.56倍,两组间差异极其显著。结论成功建立了DIO大鼠模型,通过检测脂代谢相关基因的表达水平,初步阐释了营养性肥胖的发生与脂代谢变化之间的关系,SREBP-1c,ACC,FAS和HSL参与了DIO的形成,从而初步揭示了脂代谢变化与营养性肥胖的发生的关系。     

大鼠前体脂肪细胞分化过程中6种基因的表达时序研究

本实验分离培养SD大鼠前体脂肪细胞,以油红O染色计数法区分分化的不同阶段,采用半定量RT-PCR法检测脂肪细胞分化过程中转录因子固醇调控元件结合蛋白(sterol regulatory element binding protein,SREBP-1c)、碳水化合物反应元件结合蛋白(carbohydrate responsive element binding protein,ChREBP)以及脂肪酸合成酶(fatty acid synthase,FAS)、乙酰辅酶A羧化酶(acetyl-CoA carboxylase,ACC1)、硬酯酰辅酶A去饱和酶(stearoyl-CoA desaturase,SCD)和激素敏感脂酶(hormone sensitive lipase,HSL)基因mRNA表达水平的变化。结果表明,上述基因在前体脂肪细胞阶段均不表达,SREBP-1c、FAS在分化初期表达,SREBP-1c、ChREBP、HSL、FAS、SCD在分化中期表达,6种基因在终末分化阶段均有表达。     

茶树新品系CFT-1提取物的降脂作用及其机制研究

探讨茶树新品系福茶1号绿茶对高脂血症大鼠的降脂作用及其机制。40只大鼠随机分为正常组(CON)、高脂模型组(HFD)、福茶1号绿茶组(CFT-1,200 mg/kg·d)和普通绿茶组(Fuyun6,200 mg/kg·d)。采用高脂饮食建立高脂血症大鼠模型。绿茶提取物干预8周后,检测大鼠血脂水平、血清和肝脏的抗氧化活性、血清ALT、AST活性,ELISA法检测血清TNF-α、IL-6、IL-10含量。利用HE染色观察肝脏组织病理变化,通过Western blot和qRT-PCR方法检测脂质代谢和氧化损伤相关基因乙酰辅酶A羧化酶(ACC)、核因子CCAAT增强子结合蛋白α(C/EBP-α)、脂肪酸合成酶(FAS)和固醇调节原件结合蛋白-Ic(SREBP-lc)、低密度脂蛋白受体(LDLR)和抗氧化相关基因过氧化物酶增殖激活的受体-a(PPAR-α)、1-氨基环丙烷-1羧酸氧化酶(ACO)和肉碱棕榈酰转移酶I(CPT-lα)的蛋白和mRNA表达。结果显示,CFT-1的绿茶提取物能显著降低高脂饮食引起的体重增加和血清中TC、TG、LDL-C水平的上升,显著提高血清HDL-C水平;明显减少肝细胞中脂滴的形成,减轻肝小叶炎症脂肪变性和防止肝纤维化;显著提高血清和肝脏的SOD、GSH-Px和CAT活性,降低MDA含量;显著降低血清异常升高的ALT、AST活性和TNF-α、IL-6含量,提高IL-10含量;显著抑制肝组织中ACC、FAS、SREBP-1c和C/EBP-α表达的升高,有效拮抗肝组织中LDLR、CPT-1α、PPAR-α和ACO表达的降低。并且CFT-1的绿茶提取物的上述作用优于普通绿茶。茶树新品系CFT-1提取物对高脂血症大鼠具有降血脂作用,其机制可能与提高抗氧化和抗炎能力,调节脂肪代谢有关。     

非酒精性脂肪肝病大鼠肝脏SOCS-3 的表达与吡格列酮干预研究

目的:探讨SOCS-3在非酒精性脂肪肝病(NAFLD)发病中的作用以及吡格列酮的干预作用。方法:29只雄性SD大鼠随机分为正常对照组(8只),高脂饮食组(21只)。饲养8周后,从高质饮食组随机抽取5只大鼠证实造模成功后,将该组余下的16只大鼠继续以高脂饲料喂养,并随机分为NAFLD对照组(8只);吡格列酮干预组(8只),予以吡格列酮3mg·kg-·1d-1灌胃。16周末,处死所有大鼠,检测血糖、血胰岛素、血脂、肝脏SOCS-3 mRNA和SREBP-1c mRNA表达及肝脏病理学。结果:与正常对照组相比,NAFLD组血糖、血胰岛素、血脂、肝脏脂肪变水平及肝组织SOCS-3 mRNA、SREBP1c mRNA表达显著上调。吡格列酮干预组SOCS-3 mRNA、SREBP-1c mRNA表达较NAFLD组下调,且血糖、血胰岛素、血脂、肝脏脂肪变水平下降。SOCS-3 mRNA表达水平与胰岛素抵抗指数、SREBP-1c mRNA表达水平、肝脂肪变成显著正相关。结论:SOCS-3可能通过胰岛素抵抗及上调肝组织SREBP-1c mRNA表达参与NAFLD发病,吡格列酮能抑制肝脏SOCS-3的表达,对NAFLD有一定治疗作用。     

运动对高脂饲料喂养大鼠骨骼肌和肝脏组织脂联素-脂联素受体-腺苷酸活化蛋白激酶通路的影响

目的：探讨运动影响高脂喂养大鼠骨骼肌和肝脏组织在腺苷酸活化蛋白激酶（AMPK）通路上的可能机制。方法：40只雄性SD大鼠随机分为4组（n=1 0）：正常对照组（C组）：正常饮食不运动;正常饮食运动组（E组）：正常饮食同时进行10周游泳运动;高脂饮食对照组（H组）：高脂饲料喂养不运动;高脂饮食运动组（HE组）：高脂饲料喂养同时进行10周游泳运动。采用实时荧光定量PCR检测大鼠骨骼肌和肝脏脂联系受体1（AdipoR1）,Adipo R2 mRNA表达,Western blot检测大鼠骨骼肌和肝脏腺苷酸活化蛋白激酶α（AMPKα）蛋白表达及磷酸化水平。结果：股四头肌AdipoR1 mRNA、肝脏AdipoR2 mRNA表达在H组显著低于C组（P<0.05）;HE组股四头肌和肝脏AMPKα（Thr172）磷酸化水平显著高于H组（P<0.05）,分别较H组高43.2%和51.1%。结论：高脂喂养导致大鼠骨骼肌和肝脏A dipoR1/R2 mRNA表达下调,运动提高了大鼠骨骼肌和肝脏AMPKα（Thr172）磷酸化水平。     

黄芪决明子微乳对综合因素复制的脂肪肝大鼠的影响研究

目的:研究黄芪决明子微乳(ACM)对脂肪肝大鼠的防治作用,并进行相关机理探讨.方法:采用高脂饮食饲养,灌服酒精及注射小剂量四氧化碳制备大鼠脂肪肝模型,同时给予ACM制剂进行治疗.通过检测血清TC,TG,LDL-C,HDL-C,ALT,AST等指标及肝组织中TC,TG含量,肝组织SOD活性,MDA含量等各项指标,观察肝组织病理学变化,从而考察不同剂量ACM对大鼠脂肪肝的防治作用.结果:ACM能明显改善脂肪肝大鼠肝组织病理学表现,减轻肝脂变程度;降低的血清中ALT的含量;显著升高血清HDL-C含量,降低血清TC,LDL-C,VLDL-C含量;降低肝组织TC,TG含量,降低肝组织MDA含量,增强肝组织SOD活性.结论:ACM对大鼠脂肪肝有良好的防治作用,防治机理与其具有调节血脂,降低肝脂,改善肝功能,增强肝脏抗氧化,清除肝毒性物质等作用相关.     

植物乳杆菌对非酒精性脂肪肝小鼠的肝保护机制

为了揭示植物乳杆菌对非酒精性脂肪肝小鼠的肝保护机制,本研究通过对昆明小鼠饲喂高脂高糖小鼠饲料来建立非酒精性脂肪肝小鼠模型,之后按10 m L/kg的剂量对小鼠灌胃1.0×108 CFU/mL的植物乳杆菌NCU116溶液,持续8周。研究结果显示,植物乳杆菌NCU116处理,不仅显著降低小鼠血清TC、TG和LDL水平,并升高血清HDL水平(p0.05);也显著降低小鼠的血清和肝脏中的FFA水平(p0.05);且显著抑制ALT和AST的升高;增加AMPK和ACC的磷酸化水平,并抑制了SREBP-1和FAS的表达(p0.05);同时显著升高CAT和SOD水平,并显著降低MDA水平(p0.05);显著上调Nuclear Nrf2和HO-1的表达水平,并下调Keap1水平(p0.05)。本研究结果表明植物乳杆菌NCU116对非酒精性脂肪性肝病具有保护作用,通过激活AMPK和Nrf2通路来抑制脂质代谢和氧化应激。     

ALPL缺陷加速高脂诱导小鼠肝内脂肪沉积

摘要 目的：明确肝/骨/肾型碱性磷酸酶基因（liver/bone/kidney alkaline phosphatase,ALPL）在高脂诱导肝内脂肪沉积的作用。方法：利用野生型（WT）和ALPL敲除小鼠（ALPL^+/-）,给予高脂饮食8周诱导脂肪肝模型,检测小鼠肝内脂肪沉积和血清中葡糖糖、甘油三脂及胆固醇含量,并应用RT-PCR、Western blotting和免疫荧光染色检测肝组织中脂肪酸生成和转运相关基因表达变化。结果：ALPL^+/-组在正常饮食条件下较WT组肝内脂肪沉积无明显变化,而血清中葡萄糖和胆固醇含量增加;高脂条件下,敲除ALPL小鼠肝内脂肪沉积明显增加,且伴随血清中甘油三脂含量增加。RT-PCR和Western blotting结果显示,在高脂诱导下ALPL^+/-小鼠肝组织中关键脂肪酸生成基因ACC1、ACC2和 PPAR-γ,及脂肪酸生成基因LPL表达明显增加。此外,免疫荧光染色结果显示高脂诱导下敲除ALPL小鼠肝组织中的PPAR-γ阳性肝细胞明显增加。结论：ALPL敲除促进肝内脂肪酸生成和转运,加速高脂诱导小鼠肝内脂肪沉积,为阐明脂肪肝病变分子机制提供理论支持。     

牛磺酸对HepG2细胞甘油三酯合成的影响研究

本文探讨牛磺酸对HepG2细胞甘油三酯合成的影响,为牛磺酸预防/改善机体高脂状态的深入研究提供参考。在DMEM培养基中添加0.05 mmol/L油酸建立高甘油三酯细胞模型,分别以终浓度为1、5、10、20 mmol/L的牛磺酸处理细胞24、48、72 h,测定细胞内甘油三酯水平;并检测5 mmol/L牛磺酸作用24 h后细胞内固醇调节元件结合蛋白1c(SREBP-1c)及脂肪合成相关酶乙酰辅酶A合成酶(AceCS)、乙酰辅酶A羧化酶(ACC)、脂肪酸合成酶(FAS)、长链酰基辅酶A合成酶1(ACSL1)的蛋白表达水平。1 mmol/L牛磺酸作用72 h,5和10 mmol/L牛磺酸作用24、48、72 h,20 mmol/L牛磺酸作用24和48 h均可使高脂HepG2细胞内甘油三酯水平显著下降(P<0.05);5 mmol/L牛磺酸作用24 h,高脂HepG2细胞的SREBP-1c、FAS、ACC、AceCS1、ACSL1表达明显减少(P<0.05),磷酸化ACC表达显著增加(P<0.05)。结论:牛磺酸通过调控SREBP-1c及其下游靶基因而抑制高脂HepG2细胞脂...     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.