CIC通过激活棕色脂肪组织逆转高脂膳食诱导的肥胖

摘要 目的：探讨慢性间歇性冷暴露（Chronic intermittent cold exposure,CIC）干预对小鼠棕色脂肪组织的影响及其作用机制。方法：利用高脂饲料喂养C57BL/6小鼠,建立肥胖小鼠模型,同时给予CIC处理。将动物随机分为4组：对照组（Con组）、慢性间歇性冷暴露组（CIC组）、高脂组（HF组）、高脂冷暴露组（HF+CIC组）,每组6只小鼠;CIC干预过程中,检测小鼠体重、肛温等数据。CIC处理16周后,麻醉处死小鼠取肩胛部位棕色脂肪组织, HE染色法观察棕色脂肪组织的形态学改变,Western blotting和q-PCR 检测棕色脂肪组织Cirbp、PPAR-γ、C/EBPα、PGC-1α、UCP-1等信号分子表达情况。结果：肛温变化结果显示,干预初期小鼠冷暴露前后肛温差较大,冷适应后各组无显著性差异;与Con组相比,HF组小鼠体重升高、棕色脂肪占体重的比例下降,棕色脂肪组织中Cirbp、PPAR-γ、C/EBPα表达增高,PGC-1α、UCP-1表达下降（P<0.05）;与HF组相比,HF+CIC组小鼠体重下降、棕色脂肪占体重的比例增高,棕色脂肪组织中Cirbp、PPAR-γ、C/EBPα表达下调,PGC-1α、UCP-1表达上调（P<0.05）。结论：CIC可能是通过激活Cirbp,影响PPAR-γ-PGC-1α-UCP-1信号通路的表达变化从而对棕色脂肪组织的活化产生影响,起到防治肥胖的作用。     

运动对胰岛素抵抗大鼠肝脏BIM信号通路的影响*

目的: 探究运动干预对肥胖诱导的胰岛素抵抗大鼠肝脏BIM-JNK1-IRS1-Akt信号通路的影响。方法: 40只雄性SD大鼠随机分4组(n=10):对照组(普通膳食喂养16周);高脂膳食安静组(高脂膳食喂养16周);慢性运动组(高脂膳食喂养16周且后8周进行慢性运动干预,5%体重负重的游泳运动,1 h/d,5天/周)和急性运动组(高脂膳食喂养16周后进行同样5%体重负重的6 h急性运动干预,分两个3 h进行,中间间隔休息45 min)。干预结束后,所有大鼠称重后进行口服糖耐量和胰岛素释放实验,分别使用罗氏血糖仪和大鼠胰岛素ELISA试剂盒测定血糖含量和血清胰岛素含量,以胰岛素敏感性指数衡量胰岛素抵抗状态。Western blot方法检测肝脏Bcl-2细胞死亡调节因子(BIM),磷酸化c-Jun氨基末端激酶1(p-JNK1), 磷酸化胰岛素受体底物1(p-IRS1)和磷酸化蛋白激酶B(p-Akt)蛋白水平。结果: 与对照组大鼠相比,高脂膳食安静组大鼠体重和内脏脂肪质量显著增加(P＜0.01),胰岛素敏感性指数显著下降((P＜0.01);肝脏中BIM蛋白水平显著增加(P＜0.01),JNK1和IRS1磷酸化水平显著增加(P＜0.01),Akt磷酸化水平显著下降(P＜0.01)。与高脂膳食安静组相比,慢性运动组大鼠体重和内脏脂肪质量显著降低(P＜0.01),急性运动组大鼠体重和内脏脂肪质量无明显变化。与高脂膳食安静组相比,慢性运动组和急性运动组大鼠的胰岛素敏感性指数显著提高(P＜0.05),肝脏中BIM蛋白水平显著减少(P＜0.01),JNK1和IRS1磷酸化水平显著降低(P＜0.01),Akt磷酸化水平显著增加(P＜0.01)。结论: 慢性运动降低大鼠体重和内脏脂肪质量,急性运动并不影响大鼠体重和内脏脂肪质量,但两种运动方式都可以改善肥胖诱导的胰岛素抵抗,这可能与大鼠肝脏中BIM调节的JNK1-IRS1-Akt信号通路的改变有关。     

猪骨胶原蛋白肽缓解高脂饮食诱导小鼠肝脏氧化应激的基因芯片分析

本研究探讨猪骨胶原蛋白肽降血脂作用和抑制高脂饮食诱导肝脏抗氧化应激的作用机理。40只小鼠分为5组,分别饲喂6 w正常日粮、高脂日粮、添加1.6%钙的高脂日粮、添加1%胶原蛋白肽的高脂日粮和添加1.6%钙+1%胶原蛋白肽的高脂日粮。研究发现:与正常组相比,高脂日粮小鼠血脂和体重明显升高。1.6%钙处理可抑制体重过度升高,1%胶原蛋白肽和高钙可协同抑制调节血脂,防止体重升高。高脂主要通过影响肝脏生理节律和过氧化物酶体增生物激活受体信号通路引起脂代谢异常,高钙和骨胶原蛋白肽可显著抑制肝脏氧化应激,抑制生理节律紊乱。     

高糖高脂膳食诱导大鼠肝脏ChREBPmRNA表达

目的：观察高糖高脂膳食对大鼠肝组织碳水化合物反应元件结合蛋白（ChREBP）表达的影响。方法：16只雄性SD大鼠随机分为2组,对照组给予普通饲料,高糖高脂组给予高糖高脂饲料。6周后,检测血脂和肝组织中ChREBP表达水平。结果：高糖高脂膳食组ChREBPmRNA表达水平、血总甘油三酯、总胆固醇和高密度脂蛋白浓度均显著高于对照组（P〈0．05）;血低密度脂蛋白明显低于对照组（P〈0．05）。结论：高搪高脂膳食能引起肝脏组织中碳水化合物反应元件结合蛋白表达增加。     

茶多酚对营养性肥胖大鼠肝脏自由基代谢的影响

目的:探讨茶多酚对营养性肥胖大鼠肝脏自由基代谢的影响。方法:采用高脂饲料喂养,体重(200±20)g的雄性SD大鼠32只,随机分为4组(n=8),测定各组大鼠肝脏细胞O自由基和N自由基。结果:高脂饲料组大鼠肝脏超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性显著提高,茶多酚补充组丙二醛(MDA)含量比对照组及高脂饲料组显著下降;高脂饲料组大鼠肝脏TNOS、iNOS活性及NO含量显著升高,茶多酚降低了总-氧化氮合酶(TNOS)、诱导型一氧化氮合酶(iNOS)活性及NO含量。结论:高脂饲料诱导了大鼠肝脏细胞的氧化应激状态,茶多酚提高了营养性肥胖大鼠肝脏的抗氧化能力,对营养性肥胖大鼠肝脏有一定的保护作用。     

有氧运动联合破壁蛋白核小球藻对高脂膳食大鼠脂代谢某些指标的影响

目的：研究有氧运动联合破壁蛋白核小球藻对高脂膳食大鼠脂代谢某些指标的影响。方法：55只雄性Wistar大鼠经过适应性饲养4 d后进行3 d、20 min/d的无负重游泳训练,筛选淘汰5只不适应游泳训练的大鼠后,按体重以数字随机分组法分为5组：普通膳食+安静对照组（C组）、高脂膳食+安静对照组（H组）、高脂膳食+小球藻+安静对照组（HC组）、高脂膳食+有氧运动组（HM组）、高脂膳食+有氧运动+小球藻组（HMC）,每组10只。HM组和HMC组进行6周每周6次60 min/d的无负重游泳训练。C组大鼠以普通饲料常规喂养;其余各组以高脂饲料喂养;HC组和HMC组大鼠灌胃破壁小球藻1次,灌胃剂量为3.9 g/（kg·d）,灌胃体积为5 ml/kg,其余各组ig等量生理盐水。6周后,测定大鼠Lee’s指数,取血、肝脏检测相关生化指标。结果：与C组比较,H组Lee’s指数,血清FFA、IL-6、TNF-α、TC、TG、LDL-c,肝脏FFA、IL-10显著升高（P<0.01）;血清HDL-c水平显著降低（P< 0.01）。与H组比较,HC、HM、HMC组Lee’s指数,血清FFA、IL-6、TNF-α、TC、TG、LDL-c,肝脏FFA、IL-10显著降低（P<0.05或P<0.01）;血清HDL-c水平显著升高（P<0.05或P<0.01）。与HC、HM组比较,HMC组Lee’s指数,血清FFA、IL-6、TNF-α、TC、TG、LDL-c,肝脏FFA、IL-10显著降低（P<0.05）;血清HDL-c水平显著升高（P<0.05）。结论：有氧运动和破壁蛋白核小球藻干预能够不同程度改善高脂膳食大鼠脂代谢,降低肥胖对肝脏造成的脂毒性。其中联合干预较单一干预更为有效。     

乙酸可通过增强脂肪酸β氧化治疗小鼠肥胖

目的：探讨乙酸对高脂饮食诱导的肥胖小鼠体重及脂肪酸β氧化的影响。方法：3~4w龄C57BL/6J雄性小鼠分别给予正常饲料和高脂饲料喂养4个月以诱导肥胖,然后对肥胖小鼠实施乙酸治疗5w。喂养过程结束后,心脏采血,取结肠、肝脏和性腺周围脂肪。检测血浆葡萄糖、甘油三酯（TG）、总胆固醇（TCH）和胰岛素浓度,同时检测结肠G蛋白偶联受体（GPR43、GPR41）、酪酪肽（PYY）、胰高血糖素样肽1（GLP-1）以及肝脏和脂肪肉碱脂酰转移酶（cpt）基因mRNA表达水平。结果：高脂诱导的肥胖小鼠给予乙酸治疗5w后,体重显著性下降,但日均进食量和能量摄入却显著增加（P<0.05）。肥胖小鼠的血浆葡萄糖、TG和TCH较正常小鼠,均显著升高（P<0.05）,给予乙酸治疗后,血浆TG和TCH水平均显著降低（P<0.05）。与正常小鼠相比,肥胖小鼠结肠中GPR43、GPR41、PYY和GLP1的mRNA表达量均显著性升高（P<0.05）,脂肪和肝脏中cpt1a、cpt1c、cpt2的mRNA表达显著性降低（P<0.05）;肥胖小鼠给予乙酸治疗后,结肠中上述基因mRNA表达量均显著性降低（P<0.05）,脂肪中cpt基因mRNA表达均显著性升高（P<0.05）。结论：乙酸对小鼠肥胖有较好的治疗效果,其作用机制可能是通过特异性促进脂肪组织中脂肪酸β氧化。     

高脂饮食豚鼠高密度脂蛋白代谢的特点

目的研究豚鼠高脂饮食后高密度脂蛋白代谢的特点,并与大鼠进行比较。方法将豚鼠和大鼠分别随机分为正常组（NC）和高脂组（HF）,正常组均给予普通饲料,高脂组给予高脂饲料诱导10周后,测定血清LDL-C、HDL-C水平,HDL3/HDL2比值和LCAT、CETP的表达;采用real-time RT-PCR方法检测肝脏SR-BI表达的变化。结果与正常组相比,豚鼠高脂组血清HDL-C水平显著升高,高密度脂蛋白亚型HDL3/HDL2的比值升高,血清CETP表达均显著增加,血清LCAT表达下降,肝脏SR-BI mRNA表达水平是正常组的2.27倍。而相同高脂饲料条件下,大鼠的上述指标均无明显变化。结论豚鼠摄入高脂饮食后HDL代谢与大鼠有所不同,主要表现为血清HDL-C升高,肝脏SR-BI受体表达增加,高密度脂蛋白亚型组分发生变化,大颗粒HDL2含量相对减少,小颗粒HDL3堆积,其机制与血清CETP、LCAT的变化密切相关。     

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。     

棘胸蛙（Quasipaa spinosa）对重复急性冷暴露的生理应激与适应耐受

为探讨棘胸蛙(Quasipaa spinosa)这一溪源性两栖类对环境温度极端变化做出的生理响应与适应机制,测定了该物种在反复遭受急性冷暴露(4℃,12 h)过程中其非特异性免疫反应、氧化还原状态以及热休克蛋白70(Hsp70)mRNA表达的变化,结果发现:棘胸蛙在初次冷暴露过程中外周血细胞吞噬活性(第4小时和第12小时;P0.05)、脾巨噬细胞呼吸爆发强度(第4小时和第12小时;P0.05)以及胃溶菌酶活力受到显著抑制(第12小时;P0.05);当蛙返回到22℃环境12 h后3种免疫指标均恢复到初始和对照组水平(P0.05)。经过连续7 d冷暴露后,除溶菌酶外,血细胞吞噬活性和脾巨噬细胞呼吸爆发强度均能恢复到初始和对照组水平(P0.05)。另外,冷暴露增加了肝脏和肾脏内丙二醛(MDA)的含量,但肾脏内MDA含量升高的幅度要明显大于肝脏;肝脏SOD活力和GSH含量也表现出急性和适应性升高,而肾脏仅SOD活力有所升高,暗示在低温胁迫状态下棘胸蛙肝脏氧自由基清除能力要强于肾脏。HSP70作为应激保护蛋白,当机体遭受冷暴露后肝脏Hsp70 mRNA表达量始终未呈现出应激性升高,反而受到显著抑制(P0.05)。综上所述,棘胸蛙在经历多次急性冷胁迫后体内部分非特异性免疫功能以及肝脏氧化防御系统可以产生不同程度的适应性改变。     

Quantitative proteomic analysis of short photoperiod and low-temperature responses in bark tissues of peach (<Emphasis Type="Italic">Prunus persica</Emphasis> L. Batsch)

In the temperate climate of the northern hemisphere, winter survival of woody plants is determined by the ability to acclimate to freezing temperatures and to undergo a period of dormancy. Cold acclimation in many woody plants is initially induced by short photoperiod and low, non-freezing temperatures. These two factors (5°C and short photoperiod) were used to study changes in the proteome of bark tissues of 1-year-old peach trees. Difference in-gel electrophoresis technology, a gel-based approach involving the labeling of proteins with different fluorescent dyes, was used to conduct a quantitative assessment of changes in the peach bark proteome during cold acclimation. Using this approach, we were able to identify differentially expressed proteins and to assign them to a class of either ‘temperature-responsive’ or ‘photoperiod-responsive’ proteins. The most significant factor affecting the proteome appeared to be low temperature, while the combination of low temperature and short photoperiod was shown to act either synergistically or additively on the expression of some proteins. Fifty-seven protein spots on gels were identified by mass spectrometry. They included proteins involved in carbohydrate metabolism (e.g., enolase, malate dehydrogenase, etc), defense or protective mechanisms (e.g., dehydrin, HSPs, and PR-proteins), energy production and electron transport (e.g., adenosine triphosphate synthases and lyases), and cytoskeleton organization (e.g., tubulins and actins). The information derived from the analysis of the proteome is discussed as a function of the two treatment factors: low temperature and short photoperiod. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

细胞寒害的热力学熵理论(Ⅱ)──超熵产生作为寒害稳定性判据的理论研究

本文从物质和能量交换的角度,运用非平衡态热力学超熵产生理论,分析了寒害定态的稳定性,并建立了超熵产生判据．理论分析所得的结论与实验结果基本相符．     

抗寒剂和高油菜素内酯对高原水稻抗冷性的影响

抗寒剂ＣＲ－４,高油菜素内酯ＢＲ－１２０分别浸种和喷洒在水稻二叶期叶面上,经低温暗胁迫２ｄ,根干重,根长和茎叶干重,叶片的超氧物歧化酶,过氧化物酶活性和还原性谷胱甘肽含量毕高于对照,抗性强的丽粳低温胁迫时清除活性氧的效果较好。回温恢复１￣５ｄ,抗性不同的两个品种的ＳＯＤ和ＰＯＸ活性、抗坏血酸含量继续增加,丙二醛含量都有下降。但抗性弱的秀子糯回温恢复时,清除活性氧的效果较好,ＰＯＸ活性和ＧＳＨ含量增     

柑桔抗寒研究的现状与展望

柑桔是一种经济价值极高但又常受冻害影响的亚热带果树,本文总结了柑桔抗寒研究取得的成果,介绍了对于柑桔抗寒研究还是空白但是在其他植物抗寒研究上取得的新进展,并由此提出了柑桔抗寒可在冷诱导蛋白、冷诱导基因和抗寒基因工程等方面进行探讨以及作者粗浅的研究设想。     

葡萄COR27基因的克隆与抗寒功能研究

冬季低温是制约我国葡萄和葡萄酒产业发展的主要因素之一,揭示葡萄在冷胁迫下的信号转导通路、挖掘抗寒相关基因并解析其功能,对高耐寒品种的培育具有重要的理论和应用价值。本研究在欧亚种‘玫瑰香’葡萄(Vitis vinifera L.‘Muscat Hamburg’)冷胁迫相关转录组分析的基础上,鉴定了一个抗寒候选基因,通过同源性分析将其命名为VvCOR27。VvCOR27基因的cDNA序列(1082 bp)中,其开放阅读框(ORF)为909 bp,编码302个氨基酸。同源性分析显示,13个物种的COR27蛋白均具有3个特有的保守结构域。定量RT-PCR分析表明,VvCOR27在4℃低温处理24 h后大量表达。基于基因组序列的启动子基序分析表明,VvCOR27启动子区均只含有1个EE、EEL、G-box、ABREL元件,其数量少于AtCOR27,这可能是VvCOR27响应冷胁迫较AtCOR27滞后的原因。对3个超表达VvCOR27转基因拟南芥株系的抗寒性鉴定表明,VvCOR27参与了植株对冷胁迫的应答并作为正调控因子增强了植株对冷胁迫的耐受能力。     

Characterization of a three-phase response in gloved cold-stressed fingers

Seven gloves were studied worn by eight sedentary subjects (six men and two women) exposed to cold–dry, C–D, (mean dry bulb temperature −17.2^∘C; mean dew point temperature ), and cold–wet, C–W, ( 0^∘C; ) conditions. Mean endurance times were 75 min for the C–D and 162 min for the C–W conditions. A three-phase response pattern of the temperature in the fingers was characterized. Phase I comprised an initial period during which finger temperature remained close to the pre-exposed level, due to delayed vasoconstriction in the finger. Phase II involved an exponential-like decrease of finger temperature indicative of the onset of vasoconstriction in the finger. Phase III manifested periodic finger temperature changes due to cold induced vasodilatation (CIVD). Mean wave patterns for phase III indicated approximately 3.5 waves · h⁻¹ in the C–D but only about 2 waves · h⁻¹ in the C–W condition. Extension of endurance time, due to CIVD, was defined as the difference in time between the actual end of the experiment and the time the finger-tip would have reached the set temperature endurance limit as extrapolated by a continued exponential drop. Three overall response patterns of fingers in the cold were characterized: type A exhibiting all 3 phases; type B₁ or B₂ exhibiting either phases I+II or phases II+III; and type C showing only phase II. Considerable inter- and intra-subject variability was found. In both test conditions the final physiological thermal states of the subjects were between comfortable and slightly uncomfortable but acceptable and thus did not correlate with the responses in the fingers. Accepted: 5 January 1998     

Monitoring expression profiles of Arabidopsis genes during cold acclimation and deacclimation using DNA microarrays

A comparative analysis of gene expression profiles during cold acclimation and deacclimation is necessary to elucidate the molecular mechanisms of cold stress responses in higher plants. We analyzed gene expression profiles in the process of cold acclimation and deacclimation (recovery from cold stress) using two microarray systems, the 7K RAFL cDNA microarray and the Agilent 22K oligonucleotide array. By both microarray analyses, we identified 292 genes up-regulated and 320 genes down-regulated during deacclimation, and 445 cold up-regulated genes and 341 cold down-regulated genes during cold acclimation. Many genes up-regulated during deacclimation were found to be down-regulated during cold acclimation, and vice versa. The genes up-regulated during deacclimation were classified into (1) regulatory proteins involved in further regulation of signal transduction and gene expression and (2) functional proteins involved in the recovery process from cold-stress-induced damages and plant growth. We also applied expression profiling studies to identify the key genes involved in the biosynthesis of carbohydrates and amino acids that are known to play important roles in cold acclimation. We compared genes that are regulated during deacclimation with those regulated during rehydration after dehydration to discuss the similarity and difference of each recovery process.Electronic Supplementary Material Supplementary materials are available for this article at     

Seasonal variation in physiological responses to mild cold air in young and older men

Eight men aged 60–65 years and six men aged 20–25 years, wearing only swimming trunks, were exposed to an air temperature of 17° C and 45% R.H. in each of the four seasons. The increase in the rate of metabolic heat production for the older group in the cold test was significantly higher in summer and autumn than in winter and spring (P<0.05), but did not differ in the young group between seasons. Compared to the young group the was significantly greater for the older group (due to a marked increase in four individuals) in summer and autumn (P<0.04). At the end of the period of cold exposure, the decrements of rectal temperature (T _re), mean skin temperature ( ; due to a marked decrease in four individuals) and foot skin temperature (T _foot) were significantly greater for the older group compared to the young group at all times of the year (P<0.003). Seasonal variations in the two groups were similar, e.g., theT_re gradually became smaller from summer to winter (P<0.05) and then increased slightly in the spring (P=0.07).T _foot for both groups decreased from summer to autumn (P<0.01) and remained unchanged subsequently. No seasonal variations were observed for in either group. The increase in diastolic blood pressure (BP_d) during the test was significantly smaller in winter in both groups (P<0.05). BP_d became larger again during spring in the older group (P<0.01), but remained low in the young group. The BP_d was significantly greater for the older group than the young group in winter and spring (P<0.05). Compared to young men these results suggest that older men may lose the tolerance acquired by earlier cold acclimatization as seen by the BP_d responses, and have a somewhat lower thermoregulatory capability in coping with mild cold air in all seasons.     

Modeling cold tolerance in the mountain pine beetle, Dendroctonus ponderosae

Cold-induced mortality is a key factor driving mountain pine beetle, Dendroctonus ponderosae, population dynamics. In this species, the supercooling point (SCP) is representative of mortality induced by acute cold exposure. Mountain pine beetle SCP and associated cold-induced mortality fluctuate throughout a generation, with the highest SCPs prior to and following winter. Using observed SCPs of field-collected D. ponderosae larvae throughout the developmental season and associated phloem temperatures, we developed a mechanistic model that describes the SCP distribution of a population as a function of daily changes in the temperature-dependent processes leading to gain and loss of cold tolerance. It is based on the changing proportion of individuals in three states: (1) a non cold-hardened, feeding state, (2) an intermediate state in which insects have ceased feeding, voided their gut content and eliminated as many ice-nucleating agents as possible from the body, and (3) a fully cold-hardened state where insects have accumulated a maximum concentration of cryoprotectants (e.g. glycerol). Shifts in the proportion of individuals in each state occur in response to the driving variables influencing the opposite rates of gain and loss of cold hardening. The level of cold-induced mortality predicted by the model and its relation to extreme winter temperature is in good agreement with a range of field and laboratory observations. Our model predicts that cold tolerance of D. ponderosae varies within a season, among seasons, and among geographic locations depending on local climate. This variability is an emergent property of the model, and has important implications for understanding the insect's response to seasonal fluctuations in temperature, as well as population response to climate change. Because cold-induced mortality is but one of several major influences of climate on D. ponderosae population dynamics, we suggest that this model be integrated with others simulating the insect's biology.