骨骼肌卫星细胞的研究进展

目前已证实骨骼肌是具有多向分化潜能的成体干细胞的一个储存库。研究者认为骨骼肌中至少有两种干细胞:肌肉卫星细胞(muscle satellite cells)和肌源干细胞(muscle-derived stem cells),由于骨骼肌卫星细胞占了绝大部分,因此肌肉干细胞主要指骨骼肌卫星细胞。作者主要对肌肉卫星细胞的分离、培养、纯化、鉴定及影响其增殖与分化的机制做了简要概述。     

绵羊胚胎肌源性干细胞的生物学特性

为研究绵羊胚胎肌源性干细胞的生物学特性,取30日龄的绵羊胚胎,采用联合酶消化法及差速贴壁法分离培养获得均质的肌源性干细胞,并对其进行一系列生物学特性检测。结果显示,绵羊肌源性干细胞能传代培养至35代以上;免疫荧光染色和RT-PCR鉴定肌源性干细胞表面标记物Sca-1、CD34、CD144和Desmin呈阳性表达;生长曲线和细胞周期结果显示绵羊肌源性干细胞具有较强自我更新能力;通过不同的诱导方法可以将肌源性干细胞成功地诱导为肝样细胞和胰岛样细胞,Schiff染色和双硫腙染色均呈阳性,RT-PCR检测肝样细胞特异性标记物AFP和ALB以及胰岛样细胞特异性标记物Insulin均呈阳性表达,进一步证明了其诱导分化潜能。结果表明,本试验成功地分离培养获得了均质并具有较强自我更新潜能的绵羊肌源性干细胞,这种干细胞具有向肝样细胞和胰岛样细胞分化的潜能,这为临床治疗提供了潜在的理论基础和大量的种子细胞。     

牛骨骼肌卫星细胞的分离鉴定和诱导分化

本研究对牛骨骼肌卫星细胞进行体外分离培养、诱导分化和鉴定,采用胶原酶和胰酶联用的酶消化法分离肌卫星细胞,应用差速贴壁法进行纯化,观察卫星细胞及诱导分化后肌管的形态结构,并利用标志基因的反转录PCR（RT-PCR）和免疫荧光染色方法对分化前后细胞进行鉴定。结果显示,分离出的肌卫星细胞呈梭形生长,生长状态良好,RT-PCR和免疫荧光染色显示肌卫星细胞Pax7和MyoD呈阳性表达,纯化后的肌卫星细胞纯度大于93%;诱导分化后,卫星细胞融合生长,形成的肌管状态良好,分化标志基因MyoG和MHC呈阳性表达。本研究建立了一套从牛肌肉组织中分离和鉴定肌卫星细胞的方法,可以为肌肉的发育分化和肉牛肉质改良研究提供良好的细胞模型。     

兔脂肪间质干细胞的分离培养与鉴定

取兔腹股沟皮下脂肪组织，用Ⅰ型胶原酶消化，分离培养脂肪间质干细胞（MSCs），并用免疫组化和体外诱导分化方法对其表面分子标志和多向分化潜能进行鉴定。结果显示，兔脂肪组织中能够分离培养出脂肪MSCs，该类细胞表达CD29、CD44和CD105，不表达CD34、CD45及HLA—DR表面分子标志，并具有可分化为脂肪细胞、神经细胞和成骨细胞的多向分化潜能，证实兔脂肪组织中存在具有多向分化潜能的MSCs。     

猪胎儿神经干细胞的分离培养和分化

本研究旨在从猪胎儿脑组织中分离培养神经干细胞,观察神经干细胞生长特性和体外增殖、分化特点.利用神经干细胞培养体系,从胎龄30 d的猪胎儿脑组织中分离培养神经干细胞并诱导神经干细胞贴壁分化,采用RT-PCR技术检测干细胞和分化细胞表面标志或相关基因.结果成功分离培养出神经干细胞,神经干细胞具有分化潜能.神经干细胞中Nestin表达强阳性,β-actin、DCX、Hesl、Oct4、Desmin、CD-90、Nanog和Sox2表达阳性;体外诱导的神经干细胞可以分化为星形胶质细胞(表达GFAP)、少突胶质细胞(表达GalC)和神经元细胞(表达NF、NSE和MAP2).结果提示,从猪胎儿脑组织分离神经干细胞具有可行性和有效性,神经干细胞具有自我更新、增殖和分化潜能.     

胎儿肝干细胞的分离培养与鉴定

从人胎儿肝脏中分离、纯化肝干细胞并进行鉴定。采用改进Seglen胶原酶原位灌注消化,结合Percoll密度梯度离心分离纯化胎儿肝干细胞,计数并测定细胞活性,光镜、电镜对其形态进行观察,用免疫细胞化学法(ICC)检测细胞表面标志表达情况。结果表明,所分离细胞活性率为90.80%±2.04%,细胞平均为(2.74±0.77)×107个/肝(n=10),光镜、电镜下观察其具有肝干细胞形态及超微结构特点,ICC染色,AFP、CK19、CK8及CD34等呈阳性,原代培养可形成肝干细胞集落。研究结果为人胎儿肝干细胞的存在提供了直接依据。     

小鼠骨髓间充质干细胞(MSCs)的分离纯化及其定向诱导分化为神经元样细胞

比较了全骨髓法和密度梯度离心法分离、纯化小鼠骨髓间充质干细胞，并研究了不同培养基和血清对干细胞生长的影响以及小鼠骨髓间充质干细胞的神经分化潜能。结果表明，密度梯度离心法和贴壁法结合使用可以分离纯化小鼠骨髓间充质干细胞；所获得的小鼠骨髓间充质干细胞具有诱导分化为神经元样细胞和脂肪样细胞的潜能，为小鼠骨髓间充质干细胞体外定向诱导分化的研究提供了技术支撑。     

妊娠中期猪羊水来源干细胞EGFP基因转化及体外分化

本研究旨在获得妊娠中期猪羊水来源千细胞,并通过用EGFP对干细胞进行标记,为以EGFP作为示踪标记对干细胞进行体内移植研究奠定基础.利用羊水来源干细胞培养技术体系,从胎龄60 d猪胎儿羊水中分离获得干细胞,通过脂质体介导转染将EGFP基因导入干细胞,诱导转基因干细胞向肌细胞和神经细胞分化,观察其分化特点.采用RT-PCR技术检测干细胞和分化细胞表面标志或相关基因.结果成功分离培养出妊娠中期猪羊水来源干细胞,并获得转EGFP基因干细胞.干细胞在表达EGFP的同时仍具有分化潜能.干细胞中Oct4、CD-90和Sox2表达阳性;体外诱导的干细胞能分化为肌细胞(表达myf-6和myoD)、星形胶质细胞(表达GFAP)、少突胶质细胞(表达GalC)和神经元细胞(表达NF、NSE和MAP2).研究表明,从妊娠中期猪胎儿羊水中分离干细胞具有可行性和有效性,转EGFP基因干细胞具有自我更新、增殖和分化潜能,可以用EGFP对羊水来源干细胞进行标记、追踪,为EGFP作为示踪标记对干细胞用于体内移植研究奠定了基础.     

大鼠胰腺间充质干细胞的分离鉴定及体外诱导成脂和成骨研究

从新生大鼠胰腺中分离出间充质干细胞(MSCs),研究其分化潜能,为胰腺疾病的干细胞移植治疗探寻新的细胞来源。无菌条件取出新生3 d的大鼠胰腺,通过Ⅴ型胶原酶消化获得细胞,常规培养传代、贴壁筛选法纯化细胞、吉姆萨染色观察细胞形态、流式细胞仪测定表面标志CD34和CD44;用成骨、成脂诱导剂鉴定其分化潜能。结果显示,纯化细胞在成骨诱导剂作用下被诱导成成骨细胞,在成脂诱导剂作用下被诱导成脂肪细胞。证明所纯化的细胞为尚未分化的基质细胞,而不是组织的成体细胞,它具有多向分化潜能。     

妊娠中期猪胎儿神经干细胞分离培养及分化

从妊娠中期猪胎儿(胎龄60 d)脑组织分离培养神经干细胞并诱导其贴壁分化,采用RT-PCR技术检测干细胞及其分化细胞的表面标志.结果显示,神经干细胞中DCX、Hes1、Oct4、CD-90、Nanog、Sox2和Nestin表达阳性;体外诱导的神经干细胞可以分化为星形胶质细胞(表达GFAP)、少突胶质细胞(表达GalC)和神经元细胞(表达NF、NSE和MAP2).结果表明,从妊娠中期猪胎儿脑组织可以分离神经干细胞,神经干细胞具有自我更新和分化潜能.     

Human embryonic stem cells: possibilities for future cell transplantation therapy

Human embryonic stem cells are of great importance, and Parkinson's disease is given as an example of a condition that could benefit from the development of stem cell-based transplantation therapies. The reason for this is fairly obvious: the disease is caused by the loss of only one cell type from the brain that has one major function, namely the production of dopamine. Replacement of these cells should in principle cure the disease. But what are stem cells and how far is scientific research from being able to offer stem cell-based therapy in the clinic to patients suffering from Parkinson's disease, and other chronic diseases? These questions are addressed here together with a critical evaluation of short and long-term clinical perspectives, and a discussion of possible alternatives such as adult stem cells.     

小鼠骨骼肌Desmin启动子的克隆及表达活性分析

为了研究在体细胞中小鼠Desmin基因启动子是否具有表达活性,试验根据NCBI中小鼠Desmin启动子的序列,利用生物软件Primer Premier 6.0设计序列上、下游引物,克隆小鼠基因组中Desmin启动子片段,将克隆到的Desmin启动子片段与pAcGFP1-N1载体中的CMV启动子进行置换以构建真核表达载体pAcGFP1-N1-Des,然后将pAcGFP1-N1-Des依次转染CHO-K1、COS-7、293GP和NIH-3T3等细胞后,观察绿色荧光蛋白表达活性。结果表明:克隆得到的Desmin基因上游启动子(841 bp)与NCBI序列(NT_039173.7)比对同源性为99.76%;克隆得到的启动子中含有CAAT-box、GC-box核心调控区以及MyoD等多种转录因子结合位点;所构建的pAcGFP1-N1-Des经转染COS-7、CHO-K1和Hela细胞后可观察到呈现表达活性的绿色荧光。说明克隆获得了在COS-7、CHO-K1以及Hela细胞中的具有表达活性的小鼠Desmin基因启动子。     

Male Germ Cell Transplantation

Transplantation of male germ line stem cells from a donor animal to the testes of an infertile recipient was first described in 1994. Donor germ cells colonize the recipient's testis and produce donor-derived sperm, such that the recipient male can distribute the genetic material of the germ cell donor. Germ cell transplantation represents a functional reconstitution assay for male germ line stem cells and as such has vastly increased our ability to study the biology of stem cells in the testis and define phenotypes of infertility. First developed in rodents, the technique has now been used in a number of animal species, including domestic mammals, chicken and fish. There are three major applications for this technology in animals: first, to study fundamental aspects of male germ line stem cell biology and male fertility; second, to preserve the reproductive potential of genetically valuable individuals by male germ cell transplantation within or between species; third, to produce transgenic sperm by genetic manipulation of isolated germ line stem cells and subsequent transplantation. Transgenesis through the male germ line has tremendous potential in species in which embryonic stem cells are not available and somatic cell nuclear transfer has limited success. Therefore, transplantation of male germ cells is a uniquely valuable approach for the study, preservation and manipulation of male fertility in animals.     

Isolation and Differentiation of Mesenchymal Stem Cells From Bovine Umbilical Cord Blood

Currently, mesenchymal stem cells (MSCs) are used in veterinary clinical applications. Bone marrow and adipose tissue are the most common sources of stem cells derived from adult animals. However, cord blood which is collected non‐invasively is an alternative source of stem cells other than bone marrow and adipose tissue. Moreover, high availability and lower immunogenicity of umbilical cord blood (UCB) haematopoietic stem cells compared to other sources of stem cell therapy such as bone marrow have made them a considerable source for cell therapy, but MSCs is not highly available in cord blood and their immunogenicity is poorly understood. In this study, the cells with spindle morphology from 7 of 9 bovine UCB samples were isolated and cultured. These mesenchymal stromal cells were successfully differentiated to osteocytes, chondrocytes and adipocytes. In addition, Oct‐4 and SH3 were determined by RT‐PCR assay. It is the first report of isolation, culture, characterization and differentiation of bovine umbilical stem cells.     

Effect of adipose-derived mesenchymal stem and regenerative cells on lameness in dogs with chronic osteoarthritis of the coxofemoral joints: a randomized, double-blinded, multicenter, controlled trial

Autologous stem cell therapy in the field of regenerative veterinary medicine involves harvesting tissue, such as fat, from the patient, isolating the stem and regenerative cells, and administering the cells back to the patient. Autologous adipose-derived stem cell therapy has been commercially available since 2003, and the current study evaluated such therapy in dogs with chronic osteoarthritis of the hip. Dogs treated with adipose-derived stem cell therapy had significantly improved scores for lameness and the compiled scores for lameness, pain, and range of motion compared with control dogs. This is the first randomized, blinded, placebo-controlled clinical trial reporting on the effectiveness of stem cell therapy in dogs.     

Characterization of spheres derived from canine mammary gland adenocarcinoma cell lines

There is increasing evidence for the presence of cancer stem cells in several solid tumors, and these cancer stem cells have a potential role in tumor initiation, aggression, and recurrence. The stem cell-like properties of spheres derived from canine mammary tumors remain largely elusive. We attempted to induce sphere formation using four cell lines of canine mammary adenocarcinoma, and characterized the spheres derived from a CHMp line in vitro and in vivo. The CHMp-derived spheres showed predominantly CD44⁺CD24⁻ population, higher expression of stem cell-related genes, such as CD133, Notch3 and MDR, and higher resistance to doxorubicin compared with the CHMp-derived adherent cells. Xenograft transplantations in nude mice demonstrated that only 1 × 10⁴ sphere cells were sufficient for tumor formation. Use of the sphere assay on these sphere-derived tumors showed that sphere-forming cells were present in the tumors, and were maintained in serial transplantation. We propose that spheres derived from canine mammary adenocarcinoma cell lines possess a potential characteristic of cancer stem cells. Spheres derived from canine mammary tumors could be a powerful tool with which to investigate novel therapeutic drugs and to elucidate the molecular and cellular mechanisms that underlie tumorigenesis.     

Stem cell therapy in veterinary dermatology

Background –  Adult stem cells come from many sources and have the capacity to differentiate into many cell types, including those of the skin. The most commonly studied stem cells are those termed mesenchymal stem cells (MSCs), which are easily isolated from bone marrow and adipose tissue. Mesenchymal stem cells are known to produce a wide array of cytokines that modulate the regeneration process. The ease of collection, propagation and use of these MSCs in therapy of traumatic, ischaemic and immune‐mediated skin conditions is emerging. Approach and evidence –  In traumatic and ischaemic skin damage, MSCs are used in tissue‐engineered skin and by direct injection into damaged tissue. For immune‐mediated diseases, systemic administration of stem cells can modulate the immune system. The earliest clinical work has been with autologous stem cell sources, such as adipose tissue and bone marrow. In immune‐mediated diseases, the MSCs are used to downregulate production of inflammatory cytokines and to block T‐cell activation. Cells are generally given intravenously. Multiple sclerosis, rheumatoid arthritis and lupus have been successfully treated in human clinical trials. Mesenchymal stem cells can also stimulate resident local cells, such as keratinocytes and progenitor cells, to proliferate, migrate and repair skin injury and disease. Looking ahead –  The discovery of the MSC in adipose tissue has spawned a global effort to utilize these cells in therapy of a wide range of diseases of the skin. Reconstructive surgery, scar blocking and resolution and skin regeneration have all been shown to be possible in human and animal studies.     

An in vitro study of hematopoietic progenitor cells from peripheral blood of rabbits

The purpose of this study was to isolate and cultivate a subpopulation of pluripotent stem cells (PSCs) from the peripheral blood of rabbits, which are frequently used in veterinary research as an animal model. Pluripotent stem cells, as described in human beings, are fibroblast-like cells that exhibit a CD34 marker, specific from other hematopoietic stem cells. Commonly used human commercial media has been researched for culturing rabbit PSCs. These findings allow us to contemplate the direct application of this simple and standardized methodology in several areas of study, such as of the pharmacological effect of many drugs on hematopoietic cells, veterinary practice, and even the study of new strategies in cellular therapy for some human diseases.