n-3多不饱和脂肪酸对小鼠血液外泌体中miRNA的调节和抑制肥胖作用

目的:研究体内n-3多不饱和脂肪酸(n-3 polyunsaturated fatty acids,n-3 PUFAs)含量的增加对小鼠体质量和血液中外泌体miRNAs表达的影响,探讨n-3 PUFAs通过外泌体抑制肥胖的作用机制.方法:利用能自发生成n-3 PUFAs的fat-1转基因小鼠和同窝野生型小鼠(对照),通...     

不同泌乳期人乳外泌体miRNA表达谱的研究

采用超高速离心法从人乳中提取出囊泡结构物质,从粒径、形态和外秘体特异性标记蛋白3个方面来确定提取的物质为外泌体。采用高通量测序得到不同泌乳期外泌体中microRNA(miRNA)的表达谱。对表达谱进行分析,在人乳外泌体中共检出852种miRNA,有283种miRNA在早、中、晚3个泌乳期中均有所表达。其中,表达量排名前10位的miRNA占到总量的50%以上。在外泌体中高表达的miRNA(占总外泌体miRNA表达量2%以上的)并没有受到泌乳期的显著影响;而在外泌体中低表达的一些miRNA(占总外泌体miRNA表达量0.01%以下的)容易受到泌乳期的显著影响。此外,发现在人乳外泌体中有88种miRNA与炎症相关,其中有65种在不同泌乳期均稳定表达。综上,人乳外泌体可能具有调控炎症的功能,本研究为更好地研究不同泌乳期人乳外泌体生理功能提供基础数据。     

n-3多不饱和脂肪酸分类、来源与疾病防治功能

n-3多不饱和脂肪酸包括ALA、EPA、DPA和DHA等。增加n-3多不饱和脂肪酸摄取量可以促进婴幼儿视网膜、大脑和神经系统发育；n-3多不饱和脂肪酸通过各种途径降低人体心血管疾病和炎症的发生，降低糖尿病患者血清LDL-C和TG水平，抑制体外培养的乳腺、前列腺和结肠癌细胞增生，促进细胞凋亡。     

驴乳外泌体中miRNA的测序与分析

为探究驴乳外泌体中微小RNA(miRNA)的种类和功能性,利用Illumina测序技术对驴乳外泌体中非编码小RNA(sRNA)进行测序分析,鉴定其中的miRNA并以人乳外泌体miRNA作为对照组进行生物信息学分析。驴乳外泌体中sRNA在质量控制之后,长度主要分布在18～22 nt,在其中共鉴定到212个miRNA,其中包括16种已知miRNA和196种新miRNA。基因本体论富集分析发现,驴乳外泌体miRNA的功能性与人乳相似,构成细胞、细胞器等组分;具有结合和催化活性等功能;参与细胞代谢、生物调节等过程。京都基因与基因组百科全书通路富集分析发现,驴乳外泌体miRNA参与醛固酮的合成与分泌、Hedgehog信号、线粒体调节、癌症等通路。     

牛乳外泌体中miRNA的测序与分析

采用密度梯度离心法提取牛乳外泌体,利用Illumina测序技术对外泌体中非编码小RNA(sRNA)进行测序,探索牛乳microRNA(miRNA)的表达谱。对原始序列进行质量控制,共获得3 899 629条纯净sRNA序列,长度集中于28 nt,与数据库比对后鉴定到61种已知miRNA,346种新miRNA。基因本体论富集结果表明,牛乳外泌体miRNA在细胞过程、单一生物体过程、代谢过程等生物过程发挥作用;主要构成细胞、细胞器等组成;主要参与结合、催化活性、转运蛋白活性等分子功能。京都基因与基因组百科全书通路富集结果表明,已知miRNA与新miRNA靶基因均显著富集在百日咳（ko05133）、趋化因子信号通路（ko04062）、内吞作用（ko04144）、溶酶体（ko04142）等通路,牛乳外泌体miRNA在特定信号通路中发挥重要作用。     

n-3多不饱和脂肪酸富集纯化的研究进展

n-3多不饱和脂肪酸为一类独特的生物活性物质,在生物体内具有广泛的生理功能.随着对其生理功能的认识和研究的不断深入,对n-3多不饱和脂肪酸富集纯化的研究也成为热点.主要介绍n-3多不饱和脂肪酸的富集纯化方法,并对植物种子中α-亚麻酸的富集以及鱼油中DHA和EPA富集的研究进行了综述.     

高n-3多不饱和脂肪酸鸡蛋的开发研究进展

介绍了n-3多不饱和脂肪酸类别、营养功能及使用哪些饲料原料可以生产高n-3多不饱和脂肪酸鸡蛋,分析了鸡蛋中多不饱和脂肪酸的沉积规律和影响因素,并概述了高n-3多不饱和脂肪酸鸡蛋特点,以及存在的问题和解决途径,为开发高n-3多不饱和脂肪酸鸡蛋提供依据。     

功能性n-3多不饱和脂肪酸的研究进展

脂肪酸是生命代谢活动中一种重要化合物,根据脂肪酸碳链数上的双键数将脂肪酸分为饱和脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸三类。文章对n-3多不饱和脂肪酸来源、合成过程、n-3和n-6多不饱和脂肪酸的结构差异以及生物活性进行综述,为n-3多不饱和脂肪酸在功能保健食品、医学药用领域及基础研究进一步探索与全面开发提供理论依据。     

n-6/n-3多不饱和脂肪酸比例对HepG2细胞脂代谢的影响

本文研究了不同比例n-6/n-3多不饱和脂肪酸对HepG2细胞影响,通过体外培养细胞60μM不同比例LA/ALA培养24 h,通过反转录PCR研究不同比例LA/ALA对HepG2细胞SREBP-1、FAS、HMG-CR、LDLr和Apo B蛋白等脂代谢相关基因及蛋白表达量的影响。结果表明在组1(LA)、组2(10:1 LA/ALA)、组3(5:1 LA/ALA)、组4(1:1 LA/ALA)、组5(1:5 LA/ALA)、组6(1:10LA/ALA)和组7(ALA)7组比例中,1:1 LA/ALA比例处理细胞效果最佳,此比例脂肪酸通过下调HepG2细胞SREBP-1和FAS基因的表达来降低细胞TG的含量;下调HMG-CR基因的表达,上调LDLr基因的表达来降低细胞TC和LDL-C含量;通过上调SR-B1基因表达增加胆固醇逆转运,从而实现对HepG2脂代谢的有效调控。此多不饱和脂肪酸体外营养评价模型,为n-6/n-3多不饱和脂肪酸最佳营养比例推荐及食用植物油中多不饱和脂肪酸比例营养评估提供理论依据。     

n-3多不饱和脂肪酸对不同饲料喂养大鼠血糖及血脂的影响

目的:考察n-3多不饱和脂肪酸对不同饲料喂养大鼠血糖、胰岛素及血脂的影响。方法:将SD大鼠随机分成14个组,分别为:空白对照组（普通饲料喂养）,高糖高脂对照组（高糖高脂饲料喂养）,普通饲料喂养的α-亚麻酸和深海鱼油高、中、低剂量组,高糖高脂饲料喂养的α-亚麻酸和深海鱼油高、中、低剂量组。α-亚麻酸和深海鱼油高、中、低剂量组分别灌胃150、300、600mg/kg的α-亚麻酸和深海鱼油。连续灌胃8周后,分别对各组大鼠的血糖、胰岛素和血脂四项进行测定。结果:α-亚麻酸对不同饲料喂养大鼠的血糖、胰岛素以及血脂都没有影响。与空白对照组相比,深海鱼油能使大鼠空腹血糖浓度明显升高（p<0.05）,空腹胰岛素浓度明显降低（p<0.05）。深海鱼油对TG和HDL-C无影响;但是深海鱼油能使高糖高脂饲料喂养大鼠的TC和LDL-C呈下降趋势,其中TC的水平下降具有显著性差异（与高糖高脂对照组相比,p<0.05）。结论:在150⁶00mg/kg的灌胃剂量下,α-亚麻酸对大鼠的血糖、胰岛素以及血脂都没有影响;深海鱼油对不同饲料喂养大鼠都有抑制胰岛素分泌和升高血糖的作用,同时对高糖高脂饲料喂养导致的大鼠TC水平升高有降低作用。      

超声辅助脂肪酶催化合成富含n-3多不饱和脂肪酸磷脂的研究

以脂肪酶Lipozyme TL IM为催化剂,研究了合成富含n-3多不饱和脂肪酸磷脂的最佳工艺条件,即以正庚烷:异辛烷:正已烷=8:1:1为超声介质,溶剂(mL)/底物(g)=2,酶用量为25%,超声介质中水分质量分数为2%,超声功率70 W,55℃下连续超声5.5 h,在此条件下酯交换到磷脂上的DHA和EPA总质量分数为22.99%。由此可见,通过超声辅助及酯交换条件的优化,不仅可以大大缩短反应所需的时间,而且也能充分激活Lipozyme TL IM的酶活力,从而提高酯化反应的效率。     

伊拉兔肌内磷脂n-3多不饱和脂肪酸体外抗肿瘤功效及作用机理

根据之前的研究成果体外模拟伊拉兔肌内磷脂n-3 多不饱和脂肪酸（polyunsaturated fatty acids,PUFAs） 的组成,并研究其功能特性。结果表明：采用噻唑蓝法对复合n-3 PUFAs作用的敏感细胞进行筛选,证实伊拉兔 肌内磷脂n-3 PUFAs在30～180 μmol/L剂量范围对HepG2、MV3和A375肿瘤细胞的生长均有抑制作用,且HepG2细 胞对复合肌内磷脂n-3 PUFAs的敏感度最高;HepG2的细胞形态及数量变化与复合n-3 PUFAs呈现明显的时效和量 效关系;采用膜联蛋白V-异硫氰酸荧光素和碘化丙啶双染法对肿瘤细胞进行凋亡检测,证实伊拉兔肌内复合磷脂 n-3 PUFAs的凋亡作用;进一步研究发现,复合n-3 PUFAs及其单体（α-亚麻酸、二十碳五烯酸、二十二碳五烯酸和 二十二碳六烯酸）均能够引起HepG2细胞内氧化应激的改变,它们通过显著上调细胞内丙二醛的累积量以及活性氧 的相对荧光强度水平,同时下调超氧化物歧化酶的活力实现对HepG2细胞的诱导凋亡作用,其中二十二碳六烯酸在 非酶促氧化反应中发挥主要作用,这是肌内磷脂n-3 PUFAs诱导HepG2细胞凋亡的机制之一。     

ω-3多不饱和脂肪酸在改善鸡蛋营养质量方面的研究

本文对ω-3多不饱和脂肪酸的化学结构、特性、作用及在改善鸡蛋营养质量等方面的研究进行了综述,讨论了如何通过饲喂对鸡蛋的脂肪组分加以调控,从而使其成为人类ω-3多不饱和脂肪酸的重要来源。     

Bioavailability of Eicosapentaenoic and Docosahexaenoic n-3 Polyunsaturated Fatty Acids in Salmon Patties Compared with Capsules

ABSTRACT This sequential treatment trial compared the bioavailability of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from salmon patties fortified with fish oil (DHA:EPA ratio = 1.8, total DHA + EPA about 2.2 g), unfortified salmon patties (DHA:EPA ratio = 1.9, total DHA + EPA about 1.1 g), and fish oil capsules (DHA:EPA ratio = 1.6, total DHA + EPA = 500 mg) in healthy older adults. Fortified salmon patties produced a significantly higher mean incremental area under the curve (AUC_{fasting-9 h}) than unfortified patties for plasma EPA (37.6 in contrast to 12.9 μg·h/mL, p = 0.017), for plasma DHA (103.7 in contrast to 40.8 μg·h/mL, p = 0.035) and for plasma EPA + DHA (141.2 in contrast to 53.7 μg·h/mL, p = 0.031). Plasma EPA and DHA responses were larger with the fortified than the unfortified patties, indicating that fish oil incorporated into the salmon patties was bioavailable.     

Means of Delivering Recommended Levels of Long Chain n-3 Polyunsaturated Fatty Acids in Human Diets

ABSTRACT:  n-3 Polyunsaturated fatty acids (n-3PUFA) of marine origin have been shown to be essential for brain development and cognitive function. In addition to their essentiality, the scientific literature is full of evidence to suggest that regular consumption and/or dietary supplementation with long chain n-3PUFA give several health benefits including: prevention of cardiovascular diseases, inflammatory diseases, dyslexia, and depression. Long chain n-3PUFA intake in the Western countries, including Australia, has been shown to be inadequate. This is largely due to the fact that the Western populations do not eat seafood on a regular basis because of its cost and availability, and many individuals do not like the flavor/taste/odor of seafood. Foods fortified with long chain n-3PUFA could play an important role in meeting the demands for optimal health. Marine n-3PUFA are not likely to compete with saturated, monounsaturated, and n-6PUFA as a major source of dietary fat; however, increasing the intake of foods containing marine n-3PUFA is an important strategy for the prevention of chronic illnesses. Recent developments in food technology allow fortification of foods, such as bread, dairy products, eggs, pasta, biscuits, margarines, and other spreads, without the undesirable fish odor/taste and with reasonable shelf life. There is a need to increase the amount of long chain n-3PUFA consumed per serve and optimize their bioavailability. This article reviews the foods fortified with marine n-3PUFA and their role in meeting daily requirements, and highlights the need for further research in this important area of functional foods.     

Endogenous production of n-3 and n-6 fatty acids in mammalian cells

Polyunsaturated fatty acids (PUFA) are important components of mammalian diets, and the beneficial effects of n-3 PUFA on human development and cardiovascular health have been well documented. Caenorhabditis elegans is one of the few animals known to be able to produce linoleic (LA, 18:2n-6) and alpha-linolenic (ALA, 18:3n-3) essential fatty acids. These essential PUFA are generated by the action of desaturases that successively direct the conversion of monounsaturated fatty acids (MUFA) to PUFA. The cDNA coding sequences of the C. elegans Delta(12) and n-3 fatty acid desaturases were each placed under the control of separate constitutive eukaryotic promoters and simultaneously introduced into HC11 mouse mammary epithelial cells by adenoviral transduction. Phospholipids from transduced cells showed a significant decrease in the ratios of both MUFA:PUFA and n-6:n-3 fatty acids relative to control cultures. The fatty acid profile of transduced cellular phospholipids revealed significant decreases in MUFA and arachidonic acid (20:4n-6), and increases in LA, ALA, and eicosapentaenoic acid (20:5n-3). The fatty acid composition of triacylglycerols derived from transduced cells was similarly, but less dramatically, affected. These results demonstrate the functionality of C. elegans fatty acid desaturase enzymes in mammalian cells. Expression of these desaturases in livestock might act to counterbalance the saturating effect that rumen microbial biohydrogenation has on the fatty acid profile of ruminant products, and allow for the development of novel, land-based dietary sources of n-3 PUFA.     

多不饱和脂肪酸的营养作用及其基因表达调控

多不饱和脂肪酸是一种重要的营养物质,是所有细胞膜的重要成分,具有重要的生理功能,人们越来越关注多不饱和脂肪酸的研究与应用。本文着重论述了多不饱和脂肪酸的营养功能和其调控基因表达的分子机制。