Nerve growth factor improves the muscle regeneration capacity of muscle stem cells in dystrophic muscle

Researchers have attempted to use gene- and cell-based therapies to restore dystrophin and alleviate the muscle weakness that results from Duchenne muscular dystrophy (DMD). Our research group has isolated populations of muscle-derived stem cells (MDSCs) from the postnatal skeletal muscle of mice. In comparison with satellite cells, MDSCs display an improved transplantation capacity in dystrophic mdx muscle that we attribute to their ability to undergo long-term proliferation, self-renewal, and multipotent differentiation, including differentiation toward endothelial and neuronal lineages. Here we tested whether the use of nerve growth factor (NGF) improves the transplantation efficiency of MDSCs. We used two methods of in vitro NGF stimulation: retroviral transduction of MDSCs with a CL-NGF vector and direct stimulation of MDSCs with NGF protein. Neither method of NGF treatment changed the marker profile or proliferation behavior of the MDSCs, but direct stimulation with NGF protein significantly reduced the in vitro differentiation ability of the cells. NGF stimulation also significantly enhanced the engraftment efficiency of MDSCs transplanted within the dystrophic muscle of mdx mice, resulting in the regeneration of numerous dystrophin-positive muscle fibers. These findings highlight the importance of NGF as a modulatory molecule, the study of which will broaden our understanding of its biologic role in the regeneration and repair of skeletal muscle by musclederived cells.     

Small molecules in stem cell self-renewal and differentiation

The use of stem cells in regenerative medicine is a promising approach to the treatment of disease and injury. Natural and synthetic small molecules have been shown to be useful chemical tools for controlling and manipulating the fates of cells. Small molecules can target signaling transduction pathways (for example, tyrosine kinase receptors) and affect DNA replication, cell differentiation, tumor metastasis and apoptosis. Stem cells share many properties with cancer cells and these similarities can provide insights to control and direct cell behavior; small molecules are already standard chemotherapeutics in the treatment of cancer. Libraries of small molecules have been examined for anticancer behavior (especially apoptosis), and, more recently, for stem cell self-renewal and differentiation capabilities in potential approaches to regenerative medicine. Differentiation therapy for cancer is based on the idea that cancer cells are undifferentiated embryonic-like cells and proposes to promote the differentiation and hence block cell proliferation. For example, retinoids have a role in stem cell differentiation to several lineages and have also been used to promote differentiation of acute promyeloic leukemic cells. Small molecules are also important tools for understanding mechanistic and developmental processes. Strategies for generating functional small molecule libraries have been outlined previously. In this review, we will look at several small molecules that have been described in the recent literature as effectors of stem cell self-renewal or differentiation as associated with the Wnt, Hedgehog or NF-kappaB pathways.     

NF-κB negatively impacts the myogenic potential of muscle-derived stem cells

Inhibition of the inhibitor of kappa B kinase (IKK)/nuclear factor-kappa B (NF-κB) pathway enhances muscle regeneration in injured and diseased skeletal muscle, but it is unclear exactly how this pathway contributes to the regeneration process. In this study, we examined the role of NF-κB in regulating the proliferation and differentiation of muscle-derived stem cells (MDSCs). MDSCs isolated from the skeletal muscles of p65(+/-) mice (haploinsufficient for the p65 subunit of NF-κB) had enhanced proliferation and myogenic differentiation compared to MDSCs isolated from wild-type (wt) littermates. In addition, selective pharmacological inhibition of IKKβ, an upstream activator of NF-κB, enhanced wt MDSC differentiation into myotubes in vitro. The p65(+/-) MDSCs also displayed a higher muscle regeneration index than wt MDSCs following implantation into adult mice with muscular dystrophy. Additionally, using a muscle injury model, we observed that p65(+/-) MDSC engraftments were associated with reduced inflammation and necrosis. These results suggest that inhibition of the IKK/NF-κB pathway represents an effective approach to improve the myogenic regenerative potential of MDSCs and possibly other adult stem cell populations. Moreover, our results suggest that the improved muscle regeneration observed following inhibition of IKK/NF-κB, is mediated, at least in part, through enhanced stem cell proliferation and myogenic potential.     

肌源干细胞在组织工程和再生医学的应用

背景：肌卫星细胞是肌组织损伤后修复的主要细胞来源,在肌组织再生研究领域受到广泛关注。目的：综述肌源干细胞生物学特点及在组织工程和再生医学领域的应用,探讨肌源干细胞的临床应用价值和前景。方法：应用计算机检索维普数据库和Pubrned数据库中2000年1月至2011年4月关于肌源干细胞研究应用的文章,在标题和摘要中以“肌源干细胞,肌卫星细胞,组织工程,再生医学,成体干细胞”或“MDSCs, MSCs, ASCs, regenerative medicine; tissue engineering”为检索词进行检索。选择文章内容与肌源干细胞研究应用相关文献,同一领域文献则选择近期发表或发表在权威杂志文章。初检得到189篇文献,根据纳入标准选择25篇文献进行综述分析。结果与结论：已有的动物实验和成功的临床试验表明,结合基因工程技术和组织工程的基本原则,以肌源干细胞为基础的组织工程化组织和细胞学治疗可以通过安全的措施应用于各种骨骼肌疾病、心肌疾病、泌尿系统和神经系统,为临床医生及相关疾病领域患者提供良好治愈前景。但肌源干细胞研究仍面临着许多问题。     

骨骼肌干细胞的实验研究

目的：建立人骨骼肌干细胞体外分裂分化的模式。方法：人工流产胎儿肌肉组织用胰酶和胶原酶联合消化后，经percoll密度梯离心分离骨骼肌干细胞（又称卫星细胞）。并以Matrigel为基质，在体外培养条件下观察其分裂与分化。结果：经percoll密度梯度离心，能将干细胞与成纤维细胞分离，纯度达80％以上。干细胞具有分裂、分化的潜能，在体外由成肌细胞增殖，经彼此融合成为肌管细胞，最终形成多核且具有收缩能力的骨骼肌细胞。上述分裂、分化过程历时21天，较啮齿类长。结论：人胎儿骨骼肌干细胞在体外具有分裂、分化潜能。因此，干细胞可以用作细胞移植和基因治疗的靶组织。     

Effect of VEGF on the Regenerative Capacity of Muscle Stem Cells in Dystrophic Skeletal Muscle

We have isolated a population of muscle-derived stem cells (MDSCs) that, when compared with myoblasts, display an improved regeneration capacity, exhibit better cell survival, and improve myogenesis and angiogenesis. In addition, we and others have observed that the origin of the MDSCs may reside within the blood vessel walls (endothelial cells and pericytes). Here, we investigated the role of vascular endothelial growth factor (VEGF)–mediated angiogenesis in MDSC transplantation–based skeletal muscle regeneration in mdx mice (an animal model of muscular dystrophy). We studied MDSC and MDSC transduced to overexpress VEGF; no differences were observed in vitro in terms of phenotype or myogenic differentiation. However, after in vivo transplantation, we observe an increase in angiogenesis and endogenous muscle regeneration as well as a reduction in muscle fibrosis in muscles transplanted with VEGF-expressing cells when compared to control cells. In contrast, we observe a significant decrease in vascularization and an increase in fibrosis in the muscles transplanted with MDSCs expressing soluble forms-like tyrosine kinase 1 (sFlt1) (VEGF-specific antagonist) when compared to control MDSCs. Our results indicate that VEGF-expressing cells do not increase the number of dystrophin-positive fibers in the injected mdx muscle, when compared to the control MDSCs. Together the results suggest that the transplantation of VEGF-expressing MDSCs improved skeletal muscle repair through modulation of angiogenesis, regeneration and fibrosis in the injected mdx skeletal muscle.     

microRNA-206 promotes skeletal muscle regeneration and delays progression of Duchenne muscular dystrophy in mice

Skeletal muscle injury activates adult myogenic stem cells, known as satellite cells, to initiate proliferation and differentiation to regenerate new muscle fibers. The skeletal muscle-specific microRNA miR-206 is upregulated in satellite cells following muscle injury, but its role in muscle regeneration has not been defined. Here, we show that miR-206 promotes skeletal muscle regeneration in response to injury. Genetic deletion of miR-206 in mice substantially delayed regeneration induced by cardiotoxin injury. Furthermore, loss of miR-206 accelerated and exacerbated the dystrophic phenotype in a mouse model of Duchenne muscular dystrophy. We found that miR-206 acts to promote satellite cell differentiation and fusion into muscle fibers through suppressing a collection of negative regulators of myogenesis. Our findings reveal an essential role for miR-206 in satellite cell differentiation during skeletal muscle regeneration and indicate that miR-206 slows progression of Duchenne muscular dystrophy.     

诱导人眼轮匝肌来源肌源干细胞向许旺细胞样细胞的分化

背景：肌源干细胞的优越性引导学者们尝试从人眼轮匝肌中分离该细胞,同时进行许旺细胞方向的诱导分化,为周围神经的修复提供新的种子细胞来源。目的：诱导人肌源干细胞向具有许旺细胞特性的细胞分化。方法：①收集重睑成形术中切除的上睑眼轮匝肌,经酶消化和细胞筛过滤,贴壁培养分离人肌源干细胞,予细胞特异标记物以免疫组织化学染色。②取大鼠坐骨神经分离培养许旺细胞,收集许旺细胞条件培养液。③将人肌源干细胞与许旺细胞条件培养液共培养,观察转化细胞的形态和免疫组织化学染色的变化。结果与结论：①原代培养4周时可见人肌源干细胞,与传代培养之人肌源干细胞同样呈现明显的小圆形形态,折光性强,少量细胞呈现短梭形。所有人肌源干细胞表现为 Desmin 阳性,Sca-1 染色阳性。②分离培养大鼠坐骨神经来源许旺细胞S100染色阳性率为（97.4±0.7）%。③经与许旺细胞条件培养液共培养,人肌源干细胞分化后细胞表达许旺细胞特异标记物S100,GFAP和p75。结果提示分离获得人肌源干细胞与许旺细胞条件培养液共培养,可以诱导人肌源干细胞表达许旺细胞特异标记物,初步证实了人肌源干细胞可分化为许旺细胞样细胞。     

诱导人眼轮匝肌来源肌源干细胞向许旺细胞样细胞的分化

背景:肌源干细胞的优越性引导学者们尝试从人眼轮匝肌中分离该细胞,同时进行许旺细胞方向的诱导分化,为周围神经的修复提供新的种子细胞来源。目的:诱导人肌源干细胞向具有许旺细胞特性的细胞分化。方法:①收集重睑成形术中切除的上睑眼轮匝肌,经酶消化和细胞筛过滤,贴壁培养分离人肌源干细胞,予细胞特异标记物以免疫组织化学染色。②取大鼠坐骨神经分离培养许旺细胞,收集许旺细胞条件培养液。③将人肌源干细胞与许旺细胞条件培养液共培养,观察转化细胞的形态和免疫组织化学染色的变化。结果与结论:①原代培养4周时可见人肌源干细胞,与传代培养之人肌源干细胞同样呈现明显的小圆形形态,折光性强,少量细胞呈现短梭形。所有人肌源干细胞表现为 Desmin 阳性,Sca-1 染色阳性。②分离培养大鼠坐骨神经来源许旺细胞S100染色阳性率为(97.4±0.7)%。③经与许旺细胞条件培养液共培养,人肌源干细胞分化后细胞表达许旺细胞特异标记物S100,GFAP和p75。结果提示分离获得人肌源干细胞与许旺细胞条件培养液共培养,可以诱导人肌源干细胞表达许旺细胞特异标记物,初步证实了人肌源干细胞可分化为许旺细胞样细胞。     

Characterization of human myoblast differentiation for tissue-engineering purposes by quantitative gene expression analysis

Tissue engineering of skeletal muscle is an encouraging possibility for the treatment of muscle loss through the creation of functional muscle tissue in vitro from human stem cells. Currently, the preferred stem cells are primary, non-immunogenic satellite cells ( = myoblasts). The objective of this study was to determine the expression patterns of myogenic markers within the human satellite cell population during their differentiation into multinucleated myotubes for an accurate characterization of stem cell behaviour. Satellite cells were incubated (for 1, 4, 8, 12 or 16 days) with a culture medium containing either a low [ = differentiation medium (DM)] or high [ = growth medium (GM)] concentration of growth factors. Furthermore, we performed a quantitative gene expression analysis of well-defined differentiation makers: myogenic factor 5 (MYF5), myogenin (MYOG), skeletal muscle αactin1 (ACTA1), embryonic (MYH3), perinatal (MYH8) and adult skeletal muscle myosin heavy chain (MYH1). Additionally, the fusion indices of forming myotubes of MYH1, MYH8 and ACTA1 were calculated. We show that satellite cells incubated with DM expressed multiple characteriztic features of mature skeletal muscles, verified by time-dependent upregulation of MYOG, MYH1, MYH3, MYH8 and ACTA1. However, satellite cells incubated with GM did not reveal all morphological aspects of muscle differentiation. Immunocytochemical investigations with antibodies directed against the differentiation markers showed correlations between the gene expression and differentiation. Our data provide information about time-dependent gene expression of differentiation markers in human satellite cells, which can be used for maturation analyses in skeletal muscle tissue-engineering applications.     

应用改良差速贴壁法和有限稀释技术分离培养小鼠来源肌源干细胞

背景：研究者们通过多种方法从肌组织中分离得到肌源干细胞,并应用于各类组织工程和再生医学研究。目的：结合改良的差速贴壁法和有限稀释技术分离小鼠来源肌源干细胞,并培养其单细胞克隆和亚克隆集落。方法：以新生C57BL/6小鼠四肢作为肌组织取材对象,经三重酶消化和细胞筛过滤,运用改良的差速贴壁法分离出肌源干细胞,予细胞特异标记物以免疫组织化学染色;以有限稀释技术克隆培养的方法,获得稳定的肌源干细胞单克隆和亚克隆集落。结果与结论：差速贴壁培养过程中,肌性细胞占比逐渐增高,首次贴壁1h可以获得足够数量的细胞进行第6次贴壁培养;肌源干细胞需72h左右贴壁生长,经10d左右可以增殖为300～500细胞数量的集落,细胞形态以小圆形细胞为主,并有少量梭形细胞,肌源干细胞能够维持形态并持续增殖;应用有限稀释技术可获得肌源干细胞单克隆和亚克隆集落,肌源干细胞克隆细胞均呈现Desmin染色阳性,Sca-1染色阳性,阳性率为（92.3±4.1）%。提示应用preplate法和有限稀释技术可以分离得到小鼠来源肌源干细胞及其克隆集落。     

应用改良差速贴壁法和有限稀释技术分离培养小鼠来源肌源干细胞

背景:研究者们通过多种方法从肌组织中分离得到肌源干细胞,并应用于各类组织工程和再生医学研究.目的:结合改良的差速贴壁法和有限稀释技术分离小鼠来源肌源干细胞,并培养其单细胞克隆和亚克隆集落.方法:以新生C57BL/6小鼠四肢作为肌组织取材对象,经三重酶消化和细胞筛过滤,运用改良的差速贴壁法分离出肌源干细胞,予细胞特异标记物以免疫组织化学染色;以有限稀释技术克隆培养的方法,获得稳定的肌源干细胞单克隆和亚克隆集落.结果与结论:差速贴壁培养过程中,肌性细胞占比逐渐增高,首次贴壁1 h可以获得足够数量的细胞进行第6次贴壁培养;肌源干细胞需72 h左右贴壁生长,经10 d左右可以增殖为300~500细胞数量的集落,细胞形态以小圆形细胞为主,并有少量梭形细胞,肌源干细胞能够维持形态并持续增殖;应用有限稀释技术可获得肌源干细胞单克隆和亚克隆集落,肌源干细胞克隆细胞均呈现Desmin染色阳性,Sca-1染色阳性,阳性率为(92.3±4.1)%.提示应用preplate法和有限稀释技术可以分离得到小鼠来源肌源干细胞及其克隆集落.     

Hematopoietic stem cells: An overview

Considerable efforts have been made in recent years in understanding the mechanisms that govern hematopoietic stem cell (HSC) origin, development, differentiation, self-renewal, aging, trafficking, plasticity and transdifferentiation. Hematopoiesis occurs in sequential waves in distinct anatomical locations during development and these shifts in location are accompanied by changes in the functional status of the stem cells and reflect the changing needs of the developing organism. HSCs make a choice of either self-renewal or committing to differentiation. The balance between self-renewal and differentiation is considered to be critical to the maintenance of stem cell numbers. It is still under debate if HSC can rejuvenate infinitely or if they do not possess ‘‘true” self-renewal and undergo replicative senescence such as any other somatic cell. Gene therapy applications that target HSCs offer a great potential for the treatment of hematologic and immunologic diseases. However, the clinical success has been limited by many factors. This review is intended to summarize the recent advances made in the human HSC field, and will review the hematopoietic stem cell from definition through development to clinical applications.     

Stem cell bioengineering for regenerative medicine

Stem cells can be used to treat a variety of diseases and several recent studies in animal models demonstrate the potential of bioengineering strategies targeting adult and embryonic stem cells. In order to obtain the desired cells for transplantation, stem cell bioengineering approaches entail the manipulation of environmental signals influencing cell survival, proliferation, self-renewal and differentiation. In that regard, multivariate analytical approaches have been used with success to optimise different stem cell culture processes. The genetic or molecular enhancement of stem cells is also a powerful means to control their proliferation or differentiation or to correct genetic defects in recipients. In the future, systems-level approaches have the potential to revolutionise the field of stem cell bioengineering by improving our understanding of regulatory networks controlling cellular behaviour. This advance in basic biology will be instrumental for the implementation of many stem cell-based regenerative therapies at the clinical level, as treatment accessibility will depend on the development of robust technologies to produce sufficient cell numbers.     

miRNA与干细胞的生物学行为

背景：以往对干细胞的研究主要集中在基因方面,但目前越来越多的证据表明,miRNA在干细胞的自我更新和分化过程中发挥着重要的调控作用。目的：介绍miRNA的形成及其对干细胞自我更新和多向分化的影响。方法：以＂microRNA,stem cell＂为检索词,应用计算机检索Elsevier数据库2000-01/2010-05文章;以＂miRNA,干细胞＂为检索词检索中国期刊全文数据库2000-01/2010-05文章。结果与结论：不同组织不同细胞存在自身特异的miRNA表达谱及序列特征,这可以作为某些组织或细胞的特异性分子标志。在细胞的不同发育阶段,miRNA组成不同,决定细胞的分化方向以及分化时相,是细胞＂定时＂、＂定向＂分化的＂开关＂。在各种干细胞中均存在特异性的miRNA,并且在干细胞的不同分化阶段亦有特异性miRNA表达,它们是保持干细胞自我更新和多向分化特性的关键分子之一。miRNA作为一种新的调控基因表达的小分子RNA,为干细胞的研究提供了一种新的途径。     

Stem cells and diabetes.

Diabetes mellitus is a metabolic disorder affecting 2-5% of the population. Transplantation of isolated islets of Langerhans from donor pancreata could be a cure for diabetes; however, such an approach is limited by the scarcity of the transplantation material and the long-term side effects of immunosuppressive therapy. These problems may be overcome by using a renewable source of cells, such as islet cells derived from stem cells. Stem cells are defined as clonogenic cells capable of both self-renewal and multilineage differentiation. This mean that these cells can be expanded in vivo or in vitro and differentiated to produce the desired cell type. There exist several sources of stem cells that have been demonstrated to give rise to pluripotent cell lines: 1) embryonic stem cells; 2) embryonic germ cells; 3) embryonic carcinoma cells; and 4) adult stem cells. By using in vitro differentiation and selection protocols, embryonic stem cells can be guided into specific cell lineages and selected by applying genetic selection when a marker gene is expressed. Recently, differentiation and cell selection protocols have been used to generate embryonic stem cell-derived insulin-secreting cells that normalise blood glucose when transplanted into diabetic animals. Some recent reports suggest that functional plasticity of adult stem cells may be greater than expected. The use of adult stem cells will circumvent the ethical dilemma surrounding embryonic stem cells and will allow autotransplantation. These investigations have increased the expectations that cell therapy could be one of the solutions to diabetes.     

Dystrophin delivery in dystrophin-deficient DMDmdx skeletal muscle by isogenic muscle-derived stem cell transplantation

Duchenne's muscular dystrophy (DMD) is a lethal muscle disease caused by a lack of dystrophin expression at the sarcolemma of muscle fibers. We investigated retroviral vector delivery of dystrophin in dystrophin-deficient DMD(mdx) (hereafter referred to as mdx) mice via an ex vivo approach using mdx muscle-derived stem cells (MDSCs). We generated a retrovirus carrying a functional human mini-dystrophin (RetroDys3999) and used it to stably transduce mdx MDSCs obtained by the preplate technique (MD3999). These MD3999 cells expressed dystrophin and continued to express stem cell markers, including CD34 and Sca-1. MD3999 cells injected into mdx mouse skeletal muscle were able to deliver dystrophin. Though a relatively low number of dystrophin-positive myofibers was generated within the gastrocnemius muscle, these fibers persisted for up to 24 weeks postinjection. The injection of cells from additional MDSC/Dys3999 clones into mdx skeletal muscle resulted in varying numbers of dystrophin-positive myofibers, suggesting a differential regenerating capacity among the clones. At 2 and 4 weeks postinjection, the infiltration of CD4- and CD8-positive lymphocytes and a variety of cytokines was detected within the injected site. These data suggest that the transplantation of retrovirally transduced mdx MDSCs can enable persistent dystrophin restoration in mdx skeletal muscle; however, the differential regenerating capacity observed among the MDSC/Dys3999 clones and the postinjection immune response are potential challenges facing this technology.     

Environmental cues to guide stem cell fate decision for tissue engineering applications

The human body contains a variety of stem cells capable of both repeated self-renewal and production of specialised, differentiated progeny. Critical to the implementation of these cells in tissue engineering strategies is a thorough understanding of which external signals in the stem cell microenvironment provide cues to control their fate decision in terms of proliferation or differentiation into a desired, specific phenotype. These signals must then be incorporated into tissue regeneration approaches for regulated exposure to stem cells. The precise spatial and temporal presentation of factors directing stem cell behaviour is extremely important during embryogenesis, development and natural healing events, and it is possible that this level of control will be vital to the success of many regenerative therapies. This review covers existing tissue engineering approaches to guide the differentiation of three disparate stem cell populations: mesenchymal, neural and endothelial. These progenitor cells will be of central importance in many future connective, neural and vascular tissue regeneration technologies.     

Environmental cues to guide stem cell fate decision for tissue engineering applications

The human body contains a variety of stem cells capable of both repeated self-renewal and production of specialised, differentiated progeny. Critical to the implementation of these cells in tissue engineering strategies is a thorough understanding of which external signals in the stem cell microenvironment provide cues to control their fate decision in terms of proliferation or differentiation into a desired, specific phenotype. These signals must then be incorporated into tissue regeneration approaches for regulated exposure to stem cells. The precise spatial and temporal presentation of factors directing stem cell behaviour is extremely important during embryogenesis, development and natural healing events, and it is possible that this level of control will be vital to the success of many regenerative therapies. This review covers existing tissue engineering approaches to guide the differentiation of three disparate stem cell populations: mesenchymal, neural and endothelial. These progenitor cells will be of central importance in many future connective, neural and vascular tissue regeneration technologies.     

大鼠肌源性干细胞的培养与鉴定

背景:肌源性干细胞是一种成体多能干细胞,已成为基因治疗和细胞介导的组织工程领域内的研究热点,临床应用自体肌源性干细胞注射治疗压力性尿失禁具有广泛前景。目的:探讨大鼠肌源性干细胞体外原代培养的方法,为临床应用自体肌源性干细胞注射治疗压力性尿失禁提供实验依据。设计:重复观察测量。单位:武汉大学人民医院生殖中心与泌尿外科。材料:实验于2003-12/2004-05在武汉大学人民医院泌尿外科实验室完成。选取4～6周龄雌性SD大鼠20只,XI型胶原酶、胰酶、多聚赖氨酸(Sigma公司),dispase酶(Gibco公司),鸡胚提取液(自制)。方法:①将大鼠以质量浓度为10g/L的戊巴比妥钠30g/kg腹腔麻醉后,无菌条件下取腓肠肌,置入冷DMEM培养基中,D-Hank’s液洗涤组织块,除去筋膜、肌腱、神经和血管,剪成1.0～3.0mm3小块,移入离心管。向组织中加入0.2%XI型胶原酶及0.1%的胰酶,采用胶原酶分离大鼠骨骼肌细胞。②应用差速贴壁法大鼠骨骼肌细胞进行纯化。细胞筛网过滤后接种至多聚赖氨酸包被的培养瓶中,37℃、体积分数为0.05的CO2培养箱中孵育1h,未贴壁细胞移入新的培养瓶中,加入新的培养基37℃培养1h后,未贴壁细胞再次转瓶换液,37℃培养过夜,如此反复,每次间隔24h转瓶换液,培养第5～6天贴壁的细胞即肌源性干细胞。③细胞生长到70%融合后,胰蛋白酶消化,以1∶2的比例进行传代。传代细胞消化后接种于放有盖玻片的6孔培养板中,加入生长培养基,24h后制备细胞爬片,采用免疫组织化学方法鉴定所培养细胞上特异性结蛋白抗原和干细胞抗原-1的表达。主要观察指标:肌源性干细胞的形态及其鉴定结果。结果:①肌源性干细胞的形态观察:从骨骼肌组织中分离出来的肌源性干细胞呈球形,折光性强。培养12h后开始贴壁仍为圆形,48h后贴壁完全并开始增生,细胞逐渐延展成梭形或纺锤形,有两极,体积小。随培养时间的延长,细胞相互融合形成成熟的多核肌管。②肌源性干细胞的鉴定结果:细胞特异性结蛋白抗原和干细胞抗原-1染色呈阳性,荧光显微镜可见细胞浆发出红色荧光,阳性率达90%。结论:肌原性干细胞属于成体干细胞,具有取材方便、免疫原性低、移植后存活时间长等优点。高纯度的肌原性干细胞可通过体外原代培养获取,免疫组化技术可鉴定其肌源性和干细胞特性,在组织工程和基因治疗中具有广泛的应用前景。