衰老对大鼠PPARα表达的影响及与胰岛素抵抗的关系

目的　观察衰老对过氧化体增殖物激活型受体α(PPARα)的组织表达的影响 ,在分子水平上探讨衰老过程中出现胰岛素抵抗 (IR)的可能机制。方法　用 Bergman创立的微小模型技术评价年轻鼠 (8～ 1 2 w龄 )和老年鼠 (2 4月龄 )的胰岛素敏感性 ,取大鼠肝脏提取总 RNA,采用半定量 RT- PCR法检测 PPARα及其目标基因脂蛋白脂酶 (LPL )、酰基 Co A合成酶 (ACS)、肉毒碱棕榈酰转运酶 (CPT ) m RNA水平 ,用 Westernblot法检测 PPARα蛋白表达情况。结果　与年轻鼠组比较 ,老年鼠组存在明显的 IR,而老年鼠组的 PPARα m RNA及 PPARα蛋白表达明显减少 ,目标基因 LPL、ACS、CPT m RNA也明显减少。结论　衰老过程中 PPARα表达减少可能与 IR有关     

PPAR-γ在溃疡性结肠炎粘膜中的表达

目的了解过氧化物酶增生激活受体（ＰＰＡＲ－γ）在溃疡性结肠炎（ＵＣ）患者结肠活检粘膜中的表达及其与疾病严重度的关系。方法　采用免疫组化法测定３１例ＵＣ患者和１２例对照组的结肠活检粘膜中ＰＰＡＲ－γ的表达情况。结果　ＵＣ患者受累及相对正常的结肠上皮ＰＰＡＲ－γ的表达均较正常对照组下降，三组分别为２４．７％±１．４９％、４３．８％±２．０３％、７０．２％±３．７５％（Ｐ＜０．０５），且病变越重，表达越低。结论ＵＣ患者内镜下活检粘膜中ＰＰＡＲ－γ的表达下降，并与疾病严重程度成负相关，提示其可能与ＵＣ的发病有关。     

过氧化物酶体增殖物活化受体γ在哮喘气道血管重构中的作用

目的探讨过氧化物酶体增殖物活化受体γ(PPARγ)在哮喘小鼠气道血管重构中的作用。方法50只小鼠随机分为5组:对照组、激动组、拮抗组、激素组和哮喘组。卵白蛋白雾化吸入建立小鼠哮喘模型,观察支气管肺泡灌洗液、肺组织中炎症反应和重构情况;并以western blot技术测定肺组织中PPARγ的表达水平,比较其与重构程度的关系。结果哮喘组血管管壁厚度[(4.66±0.73)μm]和血管旁胶原纤维沉积量[(22.1±2.42)μm2/μm]较对照组[(2.87±0.46)μm(、1.73±0.73)μm2/μm]明显增加;激动组和激素组中这一变化均较哮喘组明显减轻,且两组间比较无显著性差异。血管管壁厚度与气道平滑肌厚度或气道旁胶原纤维面积(r=0.576、0.692,P<0.01)以及血管旁胶原纤维面积与气道平滑肌厚度或气道旁胶原纤维面积呈正相关(r=0.825、0.928,P<0.01)。除激素组外,核内PPARγ的表达水平与气道平滑肌厚度、气道旁胶原纤维面积和血管旁胶原纤维面积呈负相关(r=-0.73、-0.85、-0.91,P<0.01),而与血管管壁厚度无相关性。结论PPARγ激动剂通过促进PPARγ的核定位,抑制哮喘的气道炎症和气道重构。     

急性胰腺炎大鼠胰腺过氧化酶体增殖物激活受体的表达

目的 检测ANP大鼠过氧化酶体增殖物激活受体γ(PPARγ)mRNA和蛋白表达的变化,探讨其意义.方法 36只SD大鼠按完全随机法分成对照组和ANP组.于术后3 h、6 h、12 h处死大鼠,分别检测血清淀粉酶含量,观察胰腺组织大体及镜下病理学改变,并采用RT-PCR和免疫组化分别检测胰腺PPARγmRNA和蛋白的表达.结果 ANP组术后6 h血清淀粉酶、胰腺大体及镜下病理分值分别为(7170.83±1635.59)U/L、6.67±1.03和13.00±2.36,均显著高于对照组(P<0.01);PPARγmRNA相对表达量为0.18±0.05,与对照组的0.22±0.03无显著差异;PPARγ蛋白相对表达量为4.17±0.98.较对照组的1.83±0.71显著升高(P<0.05).结论 ANP时PPARγ mRNA无明显下降,而PPARr蛋白明显增加.表明炎症损伤时,失活状态的PPARγ增多,同时反馈性抑制了PPARγ基因的表达.     

The Simultaneous Expression of Peroxisome Proliferator-Activated Receptor Delta and Cyclooxygenase-2 May Enhance Angiogenesis and Tumor Venous Invasion in Tissues of Colorectal Cancers

We conducted this study to evaluate the impact of the expression of peroxisome proliferator-activated receptor delta on angiogenesis in tissue samples of colorectal cancer. We examined 52 samples of primary human colorectal carcinomas and matched normal adjacent tissues to evaluate the expression of peroxisome proliferator-activated receptor delta, cyclooxygenase-2, vascular endothelial growth factor-A, and CD34 through immunohistochemical analysis. Peroxisome proliferator-activated receptor delta was expressed in 25 (48.1%), and cyclooxygenase-2 was expressed in 26 (50.0%) of total colorectal cancer tissues. Tissue samples were divided into four groups, according to the expression of peroxisome proliferator-activated receptor delta and cyclooxygenase-2. The positive rate of vascular endothelial growth factor-A, the levels of microvascular density, and the incidence of venous vessel invasion in peroxisome proliferator-activated receptor delta (+)/cyclooxygenase-2 (+) samples exceeded significantly those in the other three groups of tissue samples (P < 0.05). The results suggest that the axis of the cyclooxygenase-2/peroxisome proliferator-activated receptor delta signal pathway might play a crucial role in the development of colorectal cancers by enhancing angiogenesis.     

胆汁酸代谢主要调节核受体和相关基因在胆汁淤积孕鼠肝脏中的表达

目的 探讨法尼醇X受体(FXR)、过氧化物酶增殖体激活受体α(PPAR α)与胆固醇7 α羟化酶(CYP7A1)、胆固醇27 α羟化酶(CYP27A1)、胆固醇12 α羟化酶(CYP8B1)mRNA在妊娠期肝内胆汁淤积孕鼠肝脏中的表达及其意义.方法将60只清洁级SD大鼠自孕第13天均分为3组,对照组:皮下注射精制植物油2.0ml·kg-1·d-1;未治疗组:皮下注射17-α-乙炔雌二醇1.25 mg·kg-1·d-1;治疗组:皮下注射17-α-乙炔雌二醇1.25 mg·kg-1·d-1,孕第17天起给予非诺贝特50 mg·kg-1·d-1灌胃.3组孕鼠分别于妊娠第13、17、21天断尾采血2 ml检测血清生物化学指标,并于妊娠第21天处死,提取肝脏组织.应用酶联免疫吸附法检测3组孕鼠血清中的胆酸水平;用实时定量PCR技术检测各组PPARα、FXR、CYP7A1、CYP27A1、CYP8B1 mRNA的表达量.多组间的比较用方差分析,多组的两两间比较用Student-Newman-Keuls法检验,两组数据间比较用t检验.结果 妊娠第17天,对照组、未治疗组、治疗组的胆汁酸水平分别为(26.6±2.3)μmol/L、(68.7±4.2)μmol/L、(69.5±3.8)μmol/L,未治疗组和治疗组胆汁酸水平与对照组比较,t值分别为2.516、2.642,P值均＜0.05,差异均有统计学意义.治疗组与未治疗组之间胆汁酸水平比较,t=1.835,P＞0.05,差异无统计学意义;妊娠第21天,对照组、未治疗组、治疗组胆汁酸水平分别为(27.1±3.2) mol/L、(69.4±3.7)μmol/L、(48.5±4.8)μmol/L,3组比较,F=7.81,P＜0.05,差异有统计学意义.对照组、未治疗组、治疗组中CYP7A1 mRNA的相对表达量分别为0.75±0.02、1.55±0.03、1.25±0.01,FXR mRNA的相对表达量分别为1.25±0.03、1.75±0.02、1.65±0.05,CYP27A1 mRNA的相对表达量分别为0.65±0.03、2.45±0.01、1.65±0.02,CYP8B1 mRNA的相对表达量分别为1.50±0.02、2.15±0.01、1.75±0.03,PPARαmRNA的相对表达量分别为1.45±0.02、0.85±0.02、1.35±0.01.CYP7A1、FXR、CYP27A1、CYP8B1 mRNA在未治疗组中的表达量与对照组相比,q值分别为6.554、5.613、8.126和6.143,P值均＜0.05,差异均有统计学意义.未治疗组中PPAR α mRNA的表达量与对照组相比,q=6.126,P＜0.01,差异有统计学意义.治疗组中CYP27A1、PPAR α mRNA、CYP8B1 mRNA水平与未治疗组相比,q值分别为6.346、7.231和5.892,P值均＜0.05,差异均有统计学意义.结论胆汁酸的合成与代谢调节机制存在障碍,是导致妊娠期肝内胆汁淤积症发生的原因之一,用PPAR α的激动剂对其有一定疗效.     

罗格列酮对大鼠溃疡性结肠炎的疗效及其机制

目的观察罗格列酮对大鼠溃疡性结肠炎的疗效并探讨其可能存在的机制。方法应用三硝基苯磺酸(TNB)/乙醇灌肠制备大鼠溃疡性结肠炎模型。实验设正常对照组、模型对照组、阳性药物组(柳氮磺胺吡啶组,100 mg/kg)、罗格列酮给药组(2 mg、4mg、8 mg/kg),每天灌胃给药1次,给药时间从造模后第2天开始至实验结束共8 d,观察大鼠疾病活动指数(DAI)、结肠黏膜损伤指数(CMDI)及组织学评分(HS)。生化法检测大鼠结肠组织髓过氧化物酶(MPO)、超氧化物歧化酶(SOD)活性及丙二醛(MDA)的含量。结果与正常组相比,模型组大鼠DAI、CMDI、HS明显增加(P<0.01),结肠组织MPO活性、MDA水平显著升高(P<0.01),SOD活性下降(P<0.01)。罗格列酮4 mg、8 mg/kg和SASP可不同程度改善DAI、CMDI和HS(P<0.05,P<0.01),降低MPO活性和MDA水平(P<0.01),增加SOD活性(P<0.01)。结论罗格列酮对大鼠溃疡性结肠炎有保护作用,其机制可能与减少脂质氧化,增加清除氧自由基的能力有关。     

包头地区PPAR-γ2基因多态性与2型糖尿病合并冠心病的相关性研究

选取受试者366例，用PCR-RFLP法测定基因型（包括PP、PA、AA三种基因型，由于AA突变率很低，用X/A作为PA、AA共同代称）。发现单纯T2DM组X/A基因型频率明显低于正常对照组（0.1vs0.28；P〈0.05）；T2DM合并CHD组X/A基因型频率明显高于T2DM组（0.21vs0.1；P〈0.05）。表明在已经发生了T2DM的患者中X/A基因型是T2DM合并CHD发病的一个独立危险因素。     

非酒精性脂肪肝代谢调控与炎症反应的共同通路

非酒精性脂肪性肝病(NAFLD)是一种与胰岛素抵抗和遗传易感性密切相关的代谢应激性肝损伤,其病理变化随病程的进展表现有单纯性脂肪肝、脂肪性肝炎(NASH)及其相关的肝硬化和肝细胞癌[12].     

Berberine inhibits the expression of TNFα, MCP-1, and IL-6 in AcLDL-stimulated macrophages through PPARγ pathway

Macrophages are the main source of cytokines in atherosclerotic plaques. Modified low-density lipoproteins may stimulate macrophages to produce large quantities of proinflammatory cytokines that promote atherosclerosis. Berberine is the main component of the traditional Chinese medicine umbellatine, which has a widespread effect and was used to treat many diseases clinically. Our previous study found that berberine could increase adipophilin expression in macrophages, which is a target gene of PPARγ. PPARγ agonist could decrease proinflammatory cytokines in macrophage. In this study, we investigated the effects and the mechanism of action of berberine on the expression and secretion of TNFα, MCP-1, and IL-6 in vitro to identify new pharmacological actions of berberine. The results of RT-PCR and ELISA shows that berberine may inhibit the expression and secretion of the tumor necrosis factor α (TNFα), monocyte chemoattractant protein 1 (MCP-1), and interleukin-6 (IL-6) in macrophages stimulated by acetylated low-density lipoprotein (AcLDL), whereas the peroxisome proliferator-activated receptor γ (PPARγ) inhibitor GW9662 could attenuate this effect of berberine. This study demonstrates that berberine may inhibit the expression and production of TNF-α, MCP-1, and IL-6 in AcLDL-stimulated macrophages. This effect might be partially mediated through PPARγ activity.     

过氧化物酶体增殖物激活受体在代谢综合征大鼠血管重构和功能改变中的作用

目的 研究代谢综合征(MS)大鼠主动脉过氧化物酶体增殖物激活受体(PPARs)表达与血管重构和功能改变的关系.方法 健康8周龄雄性Wistar大鼠30只随机分为正常对照组(n=15)和MS组(n=15).MS组大鼠高脂饮食喂养24周建立MS模型.喂养连续期间检测鼠尾血压、血糖、胰岛素、血脂,24周喂养结束行葡萄糖耐量试验和高胰岛素-正常血糖钳夹试验,然后处死动物,取部分腹主动脉组织行HE染色和油红O染色,观察组织形态学改变,用图像分析系统测定内膜及中膜面积;应用多道生理仪测血管反应性,评价血管功能.取主动脉组织采用Western blot方法检测PPARγ、PPARδ和内皮型一氧化氮合酶(eNOS)蛋白表达.结果 1)MS组体质量、内脏脂肪、血压、血浆三酰甘油(TG)显著增加(P<0.05或P<0.01),且存在严重的胰岛素抵抗[GIR(1.3±0.8) vs (7.0±1.7)mg/(kg·min),P<0.01]和糖耐量减退,表现为典型的MS特征;2)与对照组相比,MS组大鼠主动脉内皮依赖和非依赖舒张功能减退;3)与对照组相比,MS组大鼠主动脉内膜增厚,中膜层平滑肌细胞增殖明显,内膜面积/中膜面积值增高,油红染色显示动脉粥样硬化明显;4)MS组大鼠主动脉PPARγ蛋白表达明显高于对照组,而PPARδ和eNOS表达明显减低.结论 MS大鼠主动脉结构重构明显和舒张功能障碍,血管组织PPARγ蛋白表达增加,而PPARδ表达减低,可能致脂质积聚,加剧炎症反应,并抑制eNOS表达,这可能是MS血管结构和功能改变的机制之一.     

Alcohol consumption in rhesus monkeys depletes tissues of polyunsaturated fatty acids and alters essential fatty acid metabolism

Rhesus monkeys that were maintained on an adequate diet but with low levels of essential fatty acids (1.4 en% linoleic, 18:2n-6, and 0.08 en%, linolenic acid, 18:3n-3) became depleted of 20:4n-6, and 22: 6n-3 in their livers, plasma lipoproteins, and erythrocytes during an 18-month period of alcohol exposure (2.6 g kg(-1) day(-1)). Monkeys that consumed alcohol also had higher plasma concentrations of 4-hydroxynonenal compared to controls. The metabolism of 18:2n-6 and 18:3n-3 were evaluated in both groups of animals using deuterium-labeled substrates over a 9-day period. Alcohol consumption did not appear to have an effect on the absorption of either 2H5-18:2n-6 or 2H5-18:3n-3 ethyl esters into the circulation after a single oral dose. However, there was a greater enrichment of deuterium in the biosynthesized fatty acids, 20:4n-6 and 22:6n-3, in the plasma of the monkeys exposed to alcohol compared to controls. These results suggest that chronic alcohol exposure may lead to a stimulation of the rate at which long-chain polyunsaturated fatty acids are biosynthesized to compensate for an increase in lipid peroxidation.     

过氧化物酶体增殖物激活受体在代谢综合征大鼠血管重构和功能改变中的作用

目的研究代谢综合征(MS)大鼠主动脉过氧化物酶体增殖物激活受体(PPARs)表达与血管重构和功能改变的关系。方法健康8周龄雄性Wistar大鼠30只随机分为正常对照组(n=15)和MS组(n=15)。MS组大鼠高脂饮食喂养24周建立MS模型。喂养连续期间检测鼠尾血压、血糖、胰岛素、血脂,24周喂养结束行葡萄糖耐量试验和高胰岛素-正常血糖钳夹试验,然后处死动物,取部分腹主动脉组织行HE染色和油红O染色,观察组织形态学改变,用图像分析系统测定内膜及中膜面积;应用多道生理仪测血管反应性,评价血管功能。取主动脉组织采用Western blot方法检测PPARγ、PPARδ和内皮型一氧化氮合酶(eNOS)蛋白表达。结果1)MS组体质量、内脏脂肪、血压、血浆三酰甘油(TG)显著增加(P<0.05或P<0.01),且存在严重的胰岛素抵抗[GIR(1.3±0.8)vs(7.0±1.7)mg/(kg.min),P<0.01]和糖耐量减退,表现为典型的MS特征;2)与对照组相比,MS组大鼠主动脉内皮依赖和非依赖舒张功能减退;3)与对照组相比,MS组大鼠主动脉内膜增厚,中膜层平滑肌细胞增殖明显,内膜面积/中膜面积值增高,油红染色显示动脉粥样硬化明显;4)MS组大鼠主动脉PPARγ蛋白表达明显高于对照组,而PPARδ和eNOS表达明显减低。结论MS大鼠主动脉结构重构明显和舒张功能障碍,血管组织PPARγ蛋白表达增加,而PPARδ表达减低,可能致脂质积聚,加剧炎症反应,并抑制eNOS表达,这可能是MS血管结构和功能改变的机制之一。     

Introduction to JMCC symposium on myocardial energy metabolism in health and disease

G. D. Lopaschuk and L. H. Opie. Introduction to JMCC Symposium on Myocardial Energy Metabolism in Health and Disease. Journal of Molecular and Cellular Cardiology (2002) 34, 1075-1076.     

The effect of adenosine on myocardial metabolism and oxygen consumption in the isolated dog heart preparation

The effects of adenosine on myocardial metabolism and oxygen consumption were examined in the isolated supported dog heart preparation (ISHP) perfused at a constant coronary blood flow. Heart rate was controlled by right atrial pacing. Coronary arterial and venous blood samples were collected and oxygen content, lactate, glucose and free fatty acid levels were determined. From arterialvenous differences and coronary blood flow, oxygen consumption and substrate uptake were determined. A 3 min intracoronary infusion of adenosine (50 and 100 μg/min) produced a significant dose-dependent decrease in MV?O₂ while increasing glucose uptake and decreasing the uptake of lactate. The decrease in oxygen consumption, the increase in glucose uptake and the decrease in the uptake of lactate were all found to be dependent on the initial MV?O₂. These findings suggest that, in addition to its putative role as a regulator of coronary vascular resistance, adenosine might also exert important metabolic effects on the heart.     

Genetic modification of the heart: transgenic modification of cardiac lipid and carbohydrate utilization

Many recent advances in cardiovascular research have been made possible by the use of transgenic technology. This review will discuss a number of mouse models where transgenic technology has been utilized to alter expression of genes involved in cardiac uptake and metabolism of either lipid or carbohydrate. Particular attention will be paid to the proteins which regulate (1) carbohydrate and lipid transport into cardiomyocytes and (2) the subsequent metabolic process which occur within the cytosol. These steps are important in determining substrate availability for mitochondrial oxidative metabolism. The heart relies predominantly on fatty acids as its major fuel supply, while glucose and lactate provide a small percentage. Under certain conditions, this balance becomes altered such that the heart relies more on glucose, as seen in pathological hypertrophy or may rely almost solely on fatty acids, as observed in cardiac tissue of animal models of diabetes. Initially this switch in metabolic substrate provides adequate energy to maintain normal cardiac function however with time diastolic dysfunction and cardiac failure often occur associated with depletion in high-energy phosphates. The creation of transgenic mice with altered expression of genes involved in carbohydrate and lipid metabolism have provided a unique insight into the fine balance which exits in the mouse heart to maintain energy status and cardiac function. The models discussed in this review define both transport and cytosolic metabolism of lipid and carbohydrate as key cellular processes in the regulation of cardiac function and the pathogenesis of cardiac disease.     

吡格列酮和非诺贝特对SD大鼠体脂分布及能量代谢的调节作用

目的观察过氧化物酶体增殖物激活受体(PPAR)-γ和-α激动剂吡格列酮、非诺贝特对高淀粉饮食SD大鼠能量代谢及体脂分布的影响。方法50只雄性SD大鼠随机分为4组:对照组(NC组),高淀粉组(SC组),高淀粉 非诺贝特组(SF组)、高淀粉 吡格列酮组(SP组)。CT测定大鼠腹部皮下脂肪面积及腹内脂肪面积。结果吡格列酮增加大鼠摄食量[(1524±145) vs (1437±162)g,P＞0．05]、摄食效率[(0．050±0．005) vs (0．044±0．004)g/kcal,p＜0．05]及体重[(428．0±20．6) vs (361．7±23．6) g,P＜0．05],与高淀粉组相比,没有进一步增加腹内脂肪及皮下脂肪面积。非诺贝特显著降低大鼠摄食量[(1174±169) vs (1437±162)g,p＜0．01]、摄食效率[(0．034±0．001) vs (0．044±0．004)g/kcal,P＜0．05]及体重[(287．7±61．5) vs (361．7±23．6)g,P＜0．01],减少总体脂含量。结论吡格列酮、非诺贝特对大鼠能量代谢及体脂分布的影响不同。     

The role of dietary salt in metabolism and energy balance: Insights beyond cardiovascular disease

Dietary salt (NaCl) is essential to an organism's survival. However, today's diets are dominated by excessive salt intake, which significantly impacts individual and population health. High salt intake is closely linked to cardiovascular disease (CVD), especially hypertension, through a number of well-studied mechanisms. Emerging evidence indicates that salt overconsumption may also be associated with metabolic disorders. In this review, we first summarize recent updates on the mechanisms of salt-induced CVD, the effects of salt reduction and the use of salt substitution as a therapy. Next, we focus on how high salt intake can impact metabolism and energy balance, describing the mechanisms through which this occurs, including leptin resistance, the overproduction of fructose and ghrelin, insulin resistance and altered hormonal factors. A further influence on metabolism worth noting is the reported role of salt in inducing thermogenesis and increasing body temperature, leading to an increase in energy expenditure. While this result could be viewed as a positive metabolic effect because it promotes a negative energy balance to combat obesity, caution must be taken with this frame of thinking given the deleterious consequences of chronic high salt intake on cardiovascular health. Nevertheless, this review highlights the importance of salt as a noncaloric nutrient in regulating whole-body energy homeostasis. Through this review, we hope to provide a scientific framework for future studies to systematically address the metabolic impacts of dietary salt and salt replacement treatments. In addition, we hope to form a foundation for future clinical trials to explore how these salt-induced metabolic changes impact obesity development and progression, and to elucidate the regulatory mechanisms that drive these changes, with the aim of developing novel therapeutics for obesity and CVD.     

The influence of chronic potassium deficiency on energy production, calcium metabolism and phospholipid composition of isolated heart mitochondria.

Rabbits were maintained for an average of 28 days either on a normal (controls) or a K⁺-deficient diet. In the low potassium group, myocardial contractility was significantly decreased revealing the cardiomyopathy. The K⁺ content of the serum as well as of the myocardial tissue was significantly decreased while the Na⁺ content in serum was higher than in the control animals. Ca²⁺ and Mg²⁺-concentrations remained unchanged. In mitochondria isolated from K⁺-depleted hearts, the state-4-respiration and the rate of Ca²⁺-uptake in the presence of ATP were increased (P < 0.001 or 0.01). Passive Ca²⁺-binding to isolated cardiac mitochondria was significantly higher as compared with controls. These data suggest that mitochondria are able to store and take up more Ca²⁺ in K⁺-deficiency. The mitochondrial phospholipid pattern shows a depression of the phosphatidylcholine content so that the phosphatidylethanolamine portion is relatively increased. A positive correlation was found between the phosphatidylethanolamine content of cardiac mitochondria and the amount of passively bound Ca²⁺. Comparing the fatty acid composition of mitochondrial phospholipids, the linoleic acid content of the cardiolipin fraction was increased in chronic K⁺-deficiency when compared with control animals. The absolute amount of linoleic acid was positively correlated to the mitochondrial state-4-respirations as well as to the ATP-dependent calcium uptake both from K⁺-depleted and normal animals.