胚胎干细胞分离培养研究进展

胚胎干细胞(ESCs)是一种高度未分化,能自我复制、自我更新,在体外连续传代并保持未分化状态和具有发育全能性的细胞.文章从研究概况、体外分离培养、生物学特性、鉴定方法、影响ESCs分离培养的因素、存在问题以及应用前景等方面对胚胎干细胞进行了概述.     

不同饲养层对牛胚胎干细胞培养的影响

本研究建立牛胚胎干细胞(Bovine Embryonic Stem Cells ESCs)的分离培养体系,摸索牛ESCs的培养条件。对牛运用FSH减量注射法进行超数排卵获取胚胎。从获得的胚胎中分离ESCs,在不同的饲养层(牛骨髓间充质干细胞、牛成纤维细胞、牛乳腺干细胞)上培养,对牛ESCs进行形态学观察及鉴定。牛MSCs做饲养层与牛SFCs、牛MaSCs相比差异显著,牛MSCs的效果最佳(P0.05)。牛ESCs在牛MSCs做饲养层的条件下更易生长。分析了不同饲养层对牛ESCs分离培养的影响,建立了一种分离培养牛ESCs的饲养层体系,为进一步深入研究ESCs的诱导分化和应用打下基础。     

近交系出路的探索(摘要)

新疆白猪“21型”是在苏联大白猪、长白猪为主导的复杂杂交群体基础上开始育种工作的,于1982年通过自治区级鉴定,正式确定为新疆白猪的一个优秀类群。当新品种培育进入横交固定阶段,根据猪群外形鉴定和各项生产性能的测定(包括个体测定和后裔测定),于1977年确定以两种不同的建系方法(即系祖建系法和群体建系法),按其生产性能分别开始为建     

山东选育出高繁良种猪繁育性能指标居国际先进水平

由山东省农科院主持的"鲁农Ⅰ号猪配套系、鲁烟白猪新品种培育与应用"项目通过鉴定。鉴定委员会认为,其整体研究达到国内同类研究的领先水平,配套系母系猪和鲁烟白猪繁育性能指标居国际先进水平。据了解,该项目利用莱芜猪、烟台黑猪培育新品种和配套     

哺乳动物精原干细胞体外培养研究进展

作者综述了哺乳动物精原干细胞体外培养的研究现状、程序及方法,并从细胞化学、免疫组织化学等方面客观评定精原干细胞体外培养的形态、结构及特征,另外,还对其体外的纯化、鉴定、应用和未来的发展方向结合自己的试验体会作了逐一说明,旨在为其体外长期培养及建系提供条件.     

猪多潜能干细胞系的研究进展

猪多潜能干细胞是在体外建立起来的具有自我更新及三胚层分化潜能的一类干细胞,可应用于发育生物学研究、基因组编辑和疾病模型建立等各方面,在畜牧业生产及再生医学研究中具有重要的应用价值。培养体系对多潜能干细胞的成功构建具有重要意义,其包含多种成分,包括基础培养液、氨基酸等营养成分、小分子化合物(信号通路激活剂/抑制剂及细胞因子)共同维持细胞的多能性并抑制其分化。目前已有诸多关于猪多潜能干细胞的报道,但尚未获得高效的培养体系可以维持猪多潜能干细胞的长期传代并完成生殖嵌合。猪多潜能干细胞可分为原始态(Na6ve)、形成态(Formative)及始发态(Primed)3种不同多能性的状态特点,根据建系来源的不同分为猪扩展多潜能干细胞、猪胚胎干细胞、猪前原肠胚上胚层干细胞、猪诱导多能干细胞4种干细胞类型。作者综述了猪多潜能干细胞培养体系中常用的细胞因子和信号通路激活剂/抑制剂对猪多潜能干细胞的多能性和分化能力的影响和作用,为进一步建立具有真正生殖嵌合能力的Na6ve多能性的猪多潜能干细胞系提供研究思路。     

应用RAPD技术对中国3品系实验用小型猪进行亲缘关系的分析

随机扩增多态ＤＮＡ (ＲａｎｄｏｍＡｍｐｌｉｆｉｅｄｐｏｌｙｍｏｒｐｈｉｃＤＮＡ ,ＲＡＰＤ)技术 ,在动物、植物、微生物种属鉴定 ,亲缘关系的划分及多态性分析中得到广泛应用 ,但应用于小型猪方面的研究报道很少 ,尤其是对我国特有的实验用小型猪的研究 ,目前国内外尚未见报道。贵州小型香猪、广西巴马小型猪及西双版纳近交系小耳猪由于其近交程度高、遗传性稳定以及良好的实验应用效果 ,已引起了国内外相关领域的关注。本实验应用 1 0 0条随机引物对上述 3品系小型猪的基因组ＤＮＡ进行ＲＡＰＤ研究 ,旨在筛选具有品系间多态性的ＲＡ…     

湘黄猪选育中几项管理措施

湘黄猪系合成系猪种，其亲本中选用了杜洛克猪和皮特兰猪。由于杜洛克猪和皮特兰猪分别带有泌乳综合症和应激敏感性等种性特点，合成建系的初期种群中不可避免地受到这类遗传基础的影响。为确保选育工作顺利进展，除从表型鉴定和基因鉴定的选择外，从管理措施上探索和研究，避开种性上的缺点来提高选育效果，其措施如下。１育种群母猪的饲养管理１．１空怀、配种和妊娠母猪的饲养管理１．１．１妊娠母猪采食量模式是前低后高，体现了能量分配的关键，以此确保胎儿正常发育和母猪生理机能和乳腺机能的正常发挥。实行早、晚精，中餐青。饲养的…     

猪胚胎干细胞培养和建系的影响因素及对策

为解决胚胎干细胞的培养和建系受血清、饲养层、细胞因子、传代时机以及其他一些不明因素影响而很不稳定的问题，在总结猪胚胎干细胞(EG)培养和建系的经验教训的基础上，对一些常规的实验方法进行了改进，提出了消除上述影响因素的对策。     

无血清分离昆明系小鼠胚胎干细胞

以昆明系小鼠胚胎为研究材料,以丝裂霉素C处理的胎鼠成纤维细胞（Mouse embryonic fibroblasts,MEF）为饲养层,在胚胎干细胞（Embryonic stemcells,ESCs）培养液中添加血清替代物（Knockout serumreplacement,KSR）以替代胎牛血清（Fetal bovine serum,FBS）,并与添加FBS的培养液进行对比,研究了昆明系小鼠胚胎贴壁、ICM（Inner cell mass,ICM）集落形成以及ESCs分离的情况。结果表明,在添加KSR的培养液中,胚胎在培养3~5 d贴壁,胚胎贴壁率显著低于添加FBS的培养液;5~7 d形成ICM集落,集落未分化形态可维持2~3 d,培养10 d ICM集落仍可保持典型的未分化形态;ICM集落形成率和1代ESCs集落出现率与添加FBS的培养液相比差异不显著（P〉0.05）,但2~5代ESCs集落出现率显著高于添加FBS的培养液,其中有2株ESCs在添加KSR的培养液中传到7代;所分离细胞显示碱性磷酸酶染色强阳性,Oct-4、Nanog的免疫组化染色阳性,具有ESCs的特点。结论：在ESCs培养液中添加KSR比添加FBS更有利于维持ICM集落及ESCs的未分化状态。     

Perspectives of germ cell development in vitro in mammals

Pluripotent stem cells, such as embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) are able to differentiate into all cell lineages of the embryo proper, including germ cells. This pluripotent property has a huge impact on the fields of regenerative medicine, developmental biology and reproductive engineering. Establishing the germ cell lineage from ESCs/iPSCs is the key biological subject, since it would contribute not only to dissection of the biological processes of germ cell development but also to production of unlimited numbers of functional gametes in vitro. Toward this goal, we recently established a culture system that induces functional mouse primordial germ cells (PGCs), precursors of all germ cells, from mouse ESCs/iPSCs. The successful in vitro production of PGCs arose from the study of pluripotent cell state, the signals inducing PGCs and the technology of transplantation. However, there are many obstacles to be overcome for the robust generation of mature gametes or for application of the culture system to other species, including humans and livestock. In this review, we discuss the requirements for a culture system to generate the germ cell lineage from ESCs/iPSCs.     

Enhancing effects of serum-rich and cytokine-supplemented culture conditions on developing blastocysts and deriving porcine parthenogenetic embryonic stem cells

The present study was conducted to develop an effective method for establishment of porcine parthenogenetic embryonic stem cells (ppESCs) from parthenogenetically activated oocyte-derived blastocysts. The addition of 10% fetal bovine serum (FBS) to the medium on the 3rd day of oocyte culturing improved the development of blastocysts, attachment of inner cell masses (ICMs) onto feeder cells, and formation of primitive ppESC colonies. ICM attachment was further enhanced by basic fibroblast growth factor, stem cell factor, and leukemia inhibitory factor. From these attached ICMs, seven ppESC lines were established. ppESC pluripotency was verified by strong enzymatic alkaline phosphatase activity and the expression of pluripotent markers OCT3/4, Nanog, and SSEA4. Moreover, the ppESCs were induced to form an embryoid body and teratoma. Differentiation into three germ layers (ectoderm, mesoderm, and endoderm) was confirmed by the expression of specific markers for the layers and histological analysis. In conclusion, data from the present study suggested that our modified culture conditions using FBS and cytokines are highly useful for improving the generation of pluripotent ppESCs.     

Generation of embryonic stem‐like cells from in vivo‐derived porcine blastocysts at a low concentration of basic fibroblast growth factor

Although basic fibroblast growth factor (bFGF) is an essential factor supporting the maintenance of porcine embryonic stem (ES) cell self‐renewal and pluripotency, its high cost has limited previous studies, and the development of a low‐cost culture system is required. For these systems, in vivo blastocysts were progressively cultured under various conditions consisting of different culture mediums and/or different feeder cell numbers at a low concentration of bFGF. As the results, the sequential culture of in vivo‐derived porcine blastocysts on 5.0 × 10⁵ mouse embryonic fibroblast (MEF) feeder cells in alpha minimum essential medium‐based medium for primary culture, on 2.5 × 10⁵ MEF feeder cells in Mixture medium for the 1st subpassage, and on 2.5 × 10⁵ MEF feeder cells in DMEM/Ham's F10‐based medium for the post‐2nd subpassage could support the establishment and maintenance of porcine ES‐like cells at the low concentration of bFGF. The established porcine ES‐like cells showed ES cell‐specific characteristics such as self‐renewal and pluripotency. We confirmed that porcine ES‐like cells could be generated from in vivo‐derived porcine blastocysts at a low concentration of bFGF.     

Recent Progress in Embryonic Stem Cell Research and Its Application in Domestic Species

Many reports described cell lines derived in domestic species, which presented several important features typical of embryonic stem cells (ESCs). Such features unfortunately did not include the capacity to generate germ-line chimeras, therefore limiting the possibility to use these cells as tools for the genetic manipulation. However, farm animal ESCs may still be useful for the generation of transgenic animals as usually have a self-renewal capacity more prolonged than normal primary cultures thus increasing the possibility to transform and select cells to be used as nucleus donors in cloning procedures. Farm animal ESCs may also be an excellent experimental model in pre-clinical trials, assessing the feasibility of cell therapy because of the close morphological and physiological resemblance to humans of species like the pig. However, the persistent lack of standard methods for the derivation, maintenance and characterization of ESCs in domestic species stimulated the search for alternatives. Embryonic germ cells may represent such an alternative. Indeed, these cells showed a higher plasticity than ESCs as contributed to embryonic development forming chimeric newborns but, as for ESCs, standardization is still far away and efficiency is very low. Recent results indicated spermatogonial stem cells as possible tools for germ-line genetic modifications with some proof of principle results already achieved. But, a real break through could arrive from the multipotent germ-line stem cells, virtually equivalent to ESC, derived from newborn and adult mouse testis.     

Knockout mouse production assisted by Blm knockdown

Production of knockout mice using targeted embryonic stem cells (ESCs) is a powerful approach for investigating the function of specific genes in vivo. Although the protocol for gene targeting via homologous recombination (HR) in ESCs is already well established, the targeting efficiency varies at different target loci and is sometimes too low. It is known that knockdown of the Bloom syndrome gene, BLM, enhances HR-mediated gene targeting efficiencies in various cell lines. However, it has not yet been investigated whether this approach in ESCs is applicable for successful knockout mouse production. Therefore, we attempted to answer this question. Consistent with previous reports, Blm knockdown enhanced gene targeting efficiencies for three gene loci that we examined by 2.3–4.1-fold. Furthermore, the targeted ESC clones generated good chimeras and were successful in germline transmission. These data suggest that Blm knockdown provides a general benefit for efficient ESC-based and HR-mediated knockout mouse production.     

Putative embryonic stem cell lines from pig embryos

Embryonic stem cells (ES cells) were first established in the mouse, and they represent a population of pluripotent, undifferentiated cells derived from early embryos that is capable of proliferating without any limitation in an undifferentiated state. These cells retain the ability to differentiate in vitro or in vivo into derivates of all three germ layers, and when injected into blastocysts, they can participate in the formation of all tissues, including gonads (germ-line chimeras). It is possible to transfect them with a gene of interest, and the resulting transgenic cell lines can also be used for production of chimeras. Unfortunately, mammalian germ-line chimeras that can carry an inserted gene into their progeny have only been produced in the mouse. Logically, before application of stem cell therapies into a human medicine, it is necessary to verify the efficiency and safety of these methods with an acceptable animal model. The pig is currently used as a very convenient animal for pre-clinical applications, and therefore establishment of porcine ES cell lines is highly needed; unfortunately, no convincing ES cell lines have been produced in this species (and other domestic animals) to date. In this article, we discuss the recent advances in this field, especially oriented on possible reasons and obstacles why derivation of porcine ES cell lines is still unsuccessful.     

胚胎干细胞分离和克隆影响因素的研究进展

胚胎干细胞ES是从早期胚胎或原始生殖细胞中分离出来的能够在体外进行传代培养,而不分化的全能性细胞,ES细胞最主要的生物学特征是具有发育的全能性或多能性,ES细胞能在体外培养、增殖、传代、冻存和诱导分化,是研究生物发育、行为和建立人体疾病模型的理想工具,本文重点论述了影响胚胎干细胞分离和克隆的因素。并展望了胚胎干细胞的应用前景。     

PPV培养细胞的选择及在ST细胞中的增值规律

猪细小病毒毒株在不同细胞系上的生长情况不尽相同,如不能掌握其规律,将难以生产出优质的疫苗.本研究对PPV（M2株）在PK15和ST细胞上生长情况进行了研究,得出ST细胞更适合其生长。之后将PPVM2毒株同步接种于ST细胞,用测定HA和TCID50的方法研究了其在ST细胞上增殖的基本规律。病毒在接种后24h可在细胞较稀的区域看到非常轻微的病变,病毒TCID50测定结果也表明,接毒后17h,病毒已经明显增殖。当病毒培养到约40h,其TCID50即接近高峰,并进入平台期,病毒的TCID50已达到10^7.5／0．hmL以上。继续培养,最高可达到10^8.5／0．1mL以上,且直到122h,也不见明显降低。病毒培养40-122h,不管是用Gibco血清还是用Hyclone血清培养病毒,其差异都非常小,变异系数都在5％以内。病毒HA价也出现同样的平台期,但HA价的平台期出现比TCID50的平台期出现更晚。