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研究脂肪生成的机理及其调控过程对于防治动物肥胖引起的相关疾病、改善肉品风味和质量以及畜牧生产效率具有重要意义。脂肪细胞起源于多能性骨髓间充质干细胞（MSCs）,接受细胞外刺激因子后迅速引起早期脂肪调节因子、C/EBPβ和C/EBPδ的表达,并传递信息至PPARγ和C/EBPα等转录因子,促进细胞的分化和脂滴形成。在此过程中,众多转录因子和细胞周期蛋白参与前体脂肪细胞到脂肪细胞的分化与成脂过程。植物来源的多种天然产物,如多酚类、生物碱、萜类、醌类化合物在脂肪细胞分化和抑制脂肪生成过程中发挥重要的调控作用,对这些天然化合物的深入和成药研究有望成为具有抑制细胞内脂滴聚集的潜在药物。 相似文献
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G J Hausman 《Journal of animal science》1985,60(6):1539-1552
The cellular and enzyme-histochemical differentiation of subcutaneous adipose tissue was studied in lean and obese pig fetuses at several ages. Positive reactions for a variety of cytosolic and organellar enzyme markers indicate metabolic competence of fetal adipocytes despite their small size (12 to 15 microns). Reactions for several enzymes decreased with fetal age and may be associated with a qualitative change in activity of adipocyte organelles. Age-associated increases in two lipogenic enzymes were observed in obese adipocytes. Observations on developing cells around hair follicles in the younger fetuses indicated significant temporal lags between the appearance of detectable enzyme activities in adipocytes. Enzyme activities in order of appearance were: dehydrogenases (cytosolic and mitochondrial), lipoprotein lipase and esterase. Esterase activity and several other enzymes were never observed in lipid positive cells that were not spherical. A proportion of hair follicle associated adipocytes in 110-d-old lean fetuses were histochemically and morphologically similar to brown adipocytes in the young rat. There was no evidence for brown adipocyte like cells in obese fetuses. Finally, comparison of the enzyme-histochemical differentiation of lean and obese fetal adipocytes indicates that fetal adipocytes become sensitive to external stimuli between 70 and 90 d of gestation. 相似文献
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旨在克隆山羊NR4A1基因的CDS区序列,明确其组织和细胞表达模式,以及探究过表达NR4A1基因对山羊皮下脂肪细胞分化的影响。本试验利用双酶切法构建山羊过表达载体pcDNA3.1-NR4A1。以1周岁简州大耳羊（n=5）为试验动物。利用RT-PCR方法和实时荧光定量PCR（real-time quantitative PCR, qPCR）技术克隆NR4A1基因编码区序列并明确其时空表达特性,再将山羊pcDNA3.1-NR4A1载体转染皮下脂肪细胞使NR4A1过表达,利用形态学方法检测过表达后脂滴聚集的变化,同时采用qPCR方法检测脂肪分化标志基因相对表达水平的变化。结果获得山羊NR4A1基因的编码区序列是1 797 bp,编码598个氨基酸;NR4A1在山羊各组织中广泛表达,且在山羊背最长肌中的相对表达水平最高（P<0.01）,在山羊皮下脂肪细胞分化60 h表达量最高（P<0.01）;过表达NR4A1基因显著促进山羊皮下脂肪细胞的脂滴积累,并且显著提高C/EBPα、C/EBPβ、PPARγ、LPL、SREBP1和AP2的相对表达水平（P<0.05）。NR4A1基因可能是山羊皮下脂肪细胞分化的正调控因子,且可能是协同脂肪分化标志基因的表达量来实现的。 相似文献
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The histology of developing porcine adipose tissue 总被引：4，自引：0，他引：4
At each of the following days after conception (45, 60, 75, 90 and 105), pig fetuses were removed from sows representing lean and fat stains. From two additional litters, postnatal pigs were sacrificed at 1, 3, 6, 9, 12, 15, 18 and 21 d. Pelikan dye was injected into fetuses and pigs. The whole of the dorsal subcutaneous tissue, including some underlying muscle, was removed. Tissue was fixed into paraffin blocks or was frozen. Paraffin and frozen sections were stained and examined for stromal-vascular and cellular changes during growth. Organized stromal-vascular changes occurred during a period of adipocyte formation from 45 d gestation until 9 d postnatally. At 45 d gestation, the subcutaneous tissue contained many short unorganized connective tissue fibers. Gradually, these fibers became more organized in a ventral to dorsal and caudal to cranial gradient, so that by 1 d postnatally, they formed complete lobules around all existing fat cell clusters. The presumptive adipose space of the complete lobules contained delicate strands of connective tissue and reacted metachromatically for mucin. Connective tissue around lobules became progressively thinner throughout the remaining postnatal ages. Vascularity of the subcutaneous tissue increased as the stromal became organized. Lipid was not present in the subcutaneous tissue at 45 d gestation, but some deposition was apparent in the inner layer at 60 d. Between 60 d gestation and 9 d postnatally, fat cells filled both subcutaneous layers in a ventral to dorsal formation. Presumptive adipose lobules were the source of adipocytes and capillaries of developing fat cell clusters. Adipocytes from fetuses through 1-d postnatal pigs were multilocular, while unilocular fat cells were first observed at 3 d. At 9 d, multilocular adipocytes were found singly or in groups within unilocular fat cell lobules. 相似文献
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哺乳动物脂肪组织主要可以分为白色脂肪组织和褐色脂肪组织,无论细胞形态还是功能,褐色脂肪与白色脂肪都有较大差别。褐色脂肪在哺乳动物产热以及能量平衡方面发挥着重要作用。为探究绵羊褐色脂肪分布特点,本研究采集了出生1、7和30 d苏尼特羊的肾周、颈部、背部、尾部、胸部、腹股沟和心包脂肪,通过HE染色、透射电镜和免疫组织化学鉴定脂肪组织类型,并通过实时荧光定量PCR和Western blot探究苏尼特羔羊不同日龄以及不同部位褐色脂肪的特点。结果发现,苏尼特羔羊体内存在两种不同类型的脂肪细胞,多室小脂滴的褐色脂肪细胞和空泡状脂滴的白色脂肪细胞。褐色脂肪细胞内有嵴的线粒体较多,并检测到褐色脂肪组织特异性蛋白UCP1的表达。而白色脂肪细胞内很少有带规则嵴的线粒体,不表达UCP1。出生1和7 d时褐色脂肪细胞数量及UCP1表达无显著差异,但出生30 d时明显下降。本研究通过形态学观察和标记基因以及蛋白检测鉴定了苏尼特羔羊的褐色脂肪和白色脂肪,证明了肾周脂肪和尾部脂肪分别是褐色脂肪以及白色脂肪的主要来源部位。出生1和7 d时苏尼特羔羊体内褐色脂肪较多,出生30 d时褐色脂肪的表型变化较大,呈现下降的趋势。本文探究了苏尼特羔羊褐色脂肪的特点,为反刍动物褐色脂肪研究提供了一定的基础。 相似文献
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胚胎干细胞的研究与应用 总被引：9，自引：0，他引：9
胚胎干细胞（ES细胞）是由早期胚胎内细胞团或盈儿原始生殖细胞分离克隆出的具有发育全能性的细胞，是动物多种组织细胞的祖细胞。由于ES细胞与克隆动物、转基因动物、组织工程、临床克隆治疗和发育生物学、遗传学以及昨动物疾病模型等研究与应用的关系密切，引起广大学者的关注和兴趣。尤其是从1999年以来，人类ES细胞研究取得很大进展，人们渴望该技术尽快成熟，应用于临床医学克隆治疗，在世界范围内掀起了ES细胞的研究热潮。海峡两岸应组织多学科、多行业、多单位的科技工作者协同攻关，使该项研究尽快取得突破性进展。 相似文献
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旨在鉴定非编码RNA circNMT1,明确其组织和细胞的表达模式,以及探究过表达circNMT1对脂肪细胞分化的影响。本试验以30月龄中国沼泽水牛(信阳水牛,n=3)的心、肝、脾、肺、肾、背最长肌、背部皮下脂肪组织和前体脂肪细胞以及3T3-L1细胞为试验材料。通过半定量PCR和实时荧光定量PCR (real-time quantitative PCR,qRT-PCR)技术对circNMT1进行鉴定、细胞定位并明确其时空表达模式。进一步分别将其过表达到3T3-L1和水牛前体脂肪细胞中,利用形态学方法及定量方法检测过表达后脂滴累积情况,同时采用qRT-PCR检测脂肪标志基因相对表达水平的变化。结果表明,circNMT1是真实存在且稳定表达的circRNA,在水牛前体脂肪细胞的细胞核和细胞质中均表达,且在脂肪组织和成熟的脂肪细胞中高表达(P<0.001)。功能获得性试验表明,在3T3-L1细胞和水牛脂肪细胞,circNMT1显著促进脂肪细胞的脂滴积累,并且显著提高成脂标志基因PPARG、C/EBPα和FABP4的相对表达水平(P<0.01)。circNMT1可能是水牛脂肪细胞分化的正调控因子,这为circNMT1在水牛脂肪细胞中的调节作用提供了新见解。 相似文献
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MK Singh KP Singh D Kumar RA Shah T Anand MS Chauhan RS Manik SK Singla P Palta 《Reproduction in domestic animals》2013,48(2):284-291
When buffalo embryonic stem (ES) cell–like cells that expressed surface markers SSEA‐4, TRA‐1‐60, TRA‐1‐81, CD9 and CD90 and intracellular markers OCT4, SOX2 and FOXD3, as shown by immunofluorescence, and that expressed REX‐1 and NUCLEOSTEMIN as confirmed by RT‐PCR, were subjected to suspension culture in hanging drops in absence of LIF and buffalo foetal fibroblast feeder layer support, they differentiated to form three‐dimensional embryoid bodies (EBs). Of 231 EBs examined on Day 3 of suspension culture, 141 (61.3 ± 3.09%) were of compact type, whereas 90 (38.4 ± 3.12%) were of cystic type. The cells obtained from EBs were found to express NF‐68 and NESTIN (ectodermal lineage), BMP‐4 and α‐skeletal actin (mesodermal lineage), and α‐fetoprotein, GATA‐4 and HNF‐4 (endodermal lineage). When these EBs were cultured on gelatin‐coated dishes, they spontaneously differentiated to several cell types such as epithelial‐ and neuron‐like cells. When EBs were cultured in the presence of 1 or 2% DMSO or 10?8 m or 10?7 m retinoic acid for 25 days, ES cells could be directed to form muscle cell–like cells, the identity of which was confirmed by expression of α‐actinin by immunofluorescence and of MYF‐5, MYOD and MYOGENIN genes by RT‐PCR. MYOD was first detected on Day 10 in both treatment groups and on Day 15 in controls, whereas MYOGENIN was first detected on Day 10, Day 15 and Day 25 in the presence of retinoic acid, in the presence of DMSO and in controls, respectively. The present study demonstrates the ability of buffalo ES cell–like cells to undergo directed differentiation to cells of skeletal myogenic lineage. 相似文献
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The development of adipocytes was studied in primary cultures of rat adipose tissue stromal-vascular cells on collagen-coated glass coverslips. The effects of cell density and serum source on lipoprotein lipase (LPL), esterase and lipid histochemistry were evaluated. With a mixture of fetal calf serum (FCS; 2%), horse serum (2%) and pig serum (PS; 10%), large and loosely arranged clusters of adipocytes developed with time through an increase in cell number and size. An inverse relationship was observed between cell size and the number of adipocytes in a cluster. Lower cell densities were associated with large cells and the densest areas contained smaller cells. Unilocular adipocytes were observed by d 13 after plating and were generally absent from the densest area of the coverslips. Histochemically detectable LPL activity was demonstrable before lipid deposition in adipocyte clusters. A comparison of FCS (10%) and PS (10%) as the only serum sources indicated higher level of adipocyte esterase activity and lipid deposition in PS cultures. Cultures of cells from weanling (21 to 28 d old) and old (18 mo) rats were similar, whereas cells from younger rats (2 to 4 d old) formed denser cultures that contained fewer adipocytes. These adipocytes were small (less than 30 micron) and morphologically homogeneous (all multilocular). When cells from the very young rats (2 to 4 d old) were plated at low densities, an inverse relationship between cell size and number of cells in a cluster was also observed.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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猪脂肪细胞特异膜蛋白的分离鉴定 总被引：6，自引：1，他引：5
用蔗糖密度梯度离心制备脂肪细胞及其他组织细胞膜蛋白 ,通过 SDS- PAGE分离并用薄层扫描测定不同组织细胞膜蛋白的组成、相对分子质量及含量。结果表明 ,猪皮下脂肪细胞有 19种膜蛋白 ,心脏、肝脏、脾脏、肺脏、肾脏、肌肉细胞及其他脂肪细胞有 13～ 2 4种膜蛋白 ,红细胞膜有 6种膜蛋白。经 Western- blot鉴定 ,猪皮下脂肪细胞有 8种特异性膜蛋白 ,分别为 110 770、10 3910、39970、3110 0、2 94 2 0、2 5 4 80、2 35 4 0和 2 2 0 0 0。结果显示 ,脂肪细胞与其他组织细胞膜蛋白组成及含量存在较大差异 相似文献
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旨在探究民猪脂肪细胞分化过程中产热基因和米色脂肪标记基因的表达变化规律，为进一步研究民猪脂肪细胞向米色脂肪细胞分化的分子机制提供依据。本研究采集1月龄民猪的背部脂肪组织，分离前体脂肪细胞进行培养及成脂诱导，观察分化过程中细胞形态并进行油红O染色鉴定；检测产热基因UCP3、PGC-1α、PPARα和米色脂肪标记基因EBF2、CD81、PDGFRα在诱导分化第0、2、4、6、8天的表达量。结果表明，随着诱导分化的时间增加，细胞中的脂滴逐渐增多，在分化第8天时进行油红O染色，多数细胞达到成熟脂肪细胞阶段。以第0天为对照，PGC-1α、EBF2、PDGFRα在第2天时表达量极显著升高（P<0.01），且达到最高，第4、6、8天呈下降趋势。UCP3在第4、6、8天表达量极显著升高（P<0.01），第8天有所下降。PPARα和CD81在第2天时表达量极显著升高（P<0.01），且在第4和6天表达量与第2天相比变化不大。综上表明，本研究成功进行了民猪前体脂肪细胞的成脂诱导分化，揭示了分化过程中产热和米色脂肪标记基因的表达规律，为进一步研究民猪前体脂肪细胞向米色脂肪细胞分化的分子机制和民猪抗寒能力奠定基础。 相似文献
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Pluripotent stem cells--model of embryonic development,tool for gene targeting,and basis of cell therapy 总被引：2，自引：0，他引：2
Embryonic stem (ES) cells are pluripotent cell lines with the capacity of self-renewal and a broad differentiation plasticity. They are derived from pre-implantation embryos and can be propagated as a homogeneous, uncommitted cell population for an almost unlimited period of time without losing their pluripotency and their stable karyotype. Murine ES cells are able to reintegrate fully into embryogenesis when returned into an early embryo, even after extensive genetic manipulation. In the resulting chimeric offspring produced by blastocyst injection or morula aggregation, ES cell descendants are represented among all cell types, including functional gametes. Therefore, mouse ES cells represent an important tool for genetic engineering, in particular via homologous recombination, to introduce gene knock-outs and other precise genomic modifications into the mouse germ line. Because of these properties ES cell technology is of high interest for other model organisms and for livestock species like cattle and pigs. However, in spite of tremendous research activities, no proven ES cells colonizing the germ line have yet been established for vertebrate species other than the mouse (Evans and Kaufman, 1981; Martin, 1981) and chicken (Pain et al., 1996). The in vitro differentiation capacity of ES cells provides unique opportunities for experimental analysis of gene regulation and function during cell commitment and differentiation in early embryogenesis. Recently, pluripotent stem cells were established from human embryos (Thomson et al., 1998) and early fetuses (Shamblott et al., 1998), opening new scenarios both for research in human developmental biology and for medical applications, i.e. cell replacement strategies. At about the same time, research activities focused on characteristics and differentiation potential of somatic stem cells, unravelling an unexpected plasticity of these cell types. Somatic stem cells are found in differentiated tissues and can renew themselves in addition to generating the specialized cell types of the tissue from which they originate. Additional to discoveries of somatic stem cells in tissues that were previously not thought to contain these kinds of cells, they also appear to be capable of developing into cell types of other tissues, but have a reduced differentiation potential as compared to embryo-derived stem cells. Therefore, somatic stem cells are referred to as multipotent rather than pluripotent. This review summarizes characteristics of pluripotent stem cells in the mouse and in selected livestock species, explains their use for genetic engineering and basic research on embryonic development, and evaluates their potential for cell therapy as compared to somatic stem cells. 相似文献
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为了探究小尾寒羊脂肪细胞分化过程中相关基因的变化规律,试验采集2月龄小尾寒羊腹股沟白色脂肪组织,通过酶消化法体外分离小尾寒羊前体脂肪细胞。培养前体脂肪细胞布满细胞板后,分别用诱导Ⅰ液、诱导Ⅱ液对细胞进行诱导分化,使其成为成熟的脂肪细胞。利用油红O染色法验证成熟脂肪细胞并检测脂滴含量。分别在增殖期细胞增殖70%、90%及分化期诱导Ⅰ液处理48 h、诱导Ⅱ液处理48 h、完全培养液处理48 h时（2、4、6、8、10 d）提取细胞总RNA,反转录成cDNA。采用实时荧光定量PCR检测PPARγ、C/EBPα、LPL、SREBP1、KLF5、KLF6、FABP4、STAT5、ACSS2、IGF1、ADD1、FOXO1、ACACA、DGAT1、CPT1A基因的表达规律。结果表明,试验成功分离并诱导前体脂肪细胞变为成熟的脂肪细胞,细胞内部具有明显脂滴;实时荧光定量PCR结果表明,上述基因在细胞分化阶段具有明显波动,峰值出现的时间均不相同;C/EBPα、FOXO1基因表达峰值出现在第6天,可能在细胞分化早期发挥作用;PPARγ、LPL、SREBP1、KLF5、KLF6、FABP4、STAT5、ADD1、ACSS2基因表达峰值出现在第8天,但表达倍数与趋势均不相同;ACACA基因表达量出现上下波动;IGF1、DGAT1基因表达峰值出现在第10天;CPT1A基因表达量则一直下降;FABP4基因表达倍数显著高于其他基因。本研究全面检测了小尾寒羊前体脂肪细胞在分化过程中关键基因的表达规律,可为探究小尾寒羊脂肪分化过程分子机制、挖掘参与脂肪分化新的关键基因、提高小尾寒羊肌间脂肪含量等研究提供一定的理论参考。 相似文献
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In vitro lipolytic response of isolated murine fat cells to epinephrine (EPI) or clenbuterol (CB) was used to evaluate the potential for the beta 2-adrenergic agonist, CB, to induce cellular resistance to further beta-adrenergic stimulation. Feeding CB (20 mg/kg diet) to mice for 1, 3 or 6 wk decreased adipocyte sensitivity to EPI or CB by 35-45%, with no differences in magnitude of this desensitization across time. Basal and maximal rates of lipolysis were similar for control- and clenbuterol-fed mice. In agreement with the feeding studies, a 2 hr preincubation of control-fat tissue with either 10 microM EPI or 100 microM CB, followed by adipocyte isolation and restimulation with EPI, reduced adipocyte sensitivity by 50%. In addition, maximal rates of lipolysis were decreased 24% and 34% for EPI and CB treated tissue, respectively. The similar adaptive responses of the adipocytes to CB exposure in vivo or in vitro suggest that CB interacts directly with fat cells in vivo and can induce tolerance. Mice fed CB for 12 wk had 33% smaller epididymal fat pads compared to controls, but pad weight differences were only 10% if feeding of CB was discontinued 1 wk before the 12 wk analysis. The reversal in fat pad gain with a 1 wk removal of CB from the diet indicates at least partial effectiveness of CB through 12 wk. The modest beta-adrenergic desensitization established by wk 1 was similar on wk 6 suggesting that CB-induced adipocyte resistance is of little consequence to the fat-reducing properties of CB administration. 相似文献
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旨在研究RNF20及其介导的组蛋白H2B第120位赖氨酸的单泛素化（H2Bub）对小鼠棕色脂肪细胞成脂分化的影响。采集1日龄和2月龄雄性C57BL/6小鼠的棕色脂肪组织（n=3），用Western blot方法检测RNF20的表达及其介导的H2Bub水平。利用胶原酶消化法分离获得1日龄小鼠的棕色前体脂肪细胞。分别诱导棕色前体脂肪细胞和C3H10T1/2细胞系成脂分化，通过油红O染色检测其分化效果，进一步通过Western blot检测细胞分化前后（0和8 d）RNF20的表达及其介导的H2Bub水平。通过siRNA干扰Rnf20基因在C3H10T1/2细胞系中的表达，油红O染色方法观察Rnf20基因对成脂分化的影响，利用qPCR和Western blot技术检测Rnf20基因的干扰效率及其介导的H2Bub水平。结果显示，2月龄小鼠棕色脂肪组织中RNF20表达量及其介导的H2Bub水平均显著高于1日龄小鼠。脂肪细胞分化标记蛋白PPARγ和CEBPα的表达水平，RNF20表达量及其介导的H2Bub水平在棕色前体脂肪细胞及C3H10T1/2细胞成脂分化后均显著增加。此外，在C3H10T1/2细胞中敲降Rnf20基因后，与阴性对照组相比，RNF20及其介导的H2Bub水平显著降低，成脂分化后脂滴明显减少。综上表明，RNF20对小鼠棕色脂肪细胞的分化是必需的，敲降Rnf20基因导致组蛋白H2Bub水平显著降低，且降低了C3H10T1/2细胞的成脂分化效率。本研究丰富了小鼠棕色脂肪细胞分化过程中的表观遗传调控研究，为深入理解动物脂肪细胞分化提供了新的基因素材。 相似文献