胚胎干细胞体外分化为成骨细胞研究进展

目的 对胚胎干细胞（embryonic stem cells，ESCs）体外诱导分化为成骨细胞的研究现状、诱导分化中存在的问题，以及进一步的研究方向作一综述。方法广泛查阅近年来关于ESCs体外诱导分化为成骨细胞的文献，并进行总结与分析。结果ESCs可以作为理想的成骨细胞种子细胞来源。结论诱导ESCs定向分化得到骨组织工程种子细胞——成骨细胞有巨大的应用潜力，不仅提供了分析成骨细胞发生的分子机制模型，而且奠定了其在骨组织修复中的基础。     

成人骨髓间充质干细胞体外诱导分化为软骨细胞的实验研究

目的研究体外三维培养条件下,成人骨髓间充质干细胞(BMSCs)定向分化软骨细胞可行性。方法用密度梯度离心法分离纯化BMSCs,并传代扩增后,用离心三维培养法在软骨诱导剂下进行诱导培养,以常规培养液培养的BMSCs作为阴性对照,于诱导培养第21天取出标本行苏木精-伊红染色、甲苯胺蓝染色、s-100蛋白免疫组织化学检测。结果BMSCs经21d的离心三维诱导培养后,培养管出现软骨外观组织块,组织切片甲苯胺蓝染色呈明显异染,s-100蛋白免疫细胞化学检测阳性。对照组阴性。结论成人BMSCs在三维培养条件下可成功诱导分化为软骨细胞。     

胚胎干细胞向生殖细胞的分化研究进展

胚胎干细胞（Embryonic Stem cell，ES cell）是从囊胚内细胞团中获得的具多能性的细胞。最近有研究报道，小鼠ES细胞在体外可分化为卵母细胞和精子。这一进展不仅为生殖细胞发生机制的研究提供一个重要的体外模型系统；而且在医学上，可为众多的不孕不育症患者带来新的希望。     

胚胎干细胞定向分化为肝脏细胞的研究进展

胚胎干细胞可由哺乳动物的囊胚内细胞群或着床后胚胎组织生殖嵴的原始生殖细胞中分离获得,也可以由核移植克隆技术获得;胚胎干细胞向肝脏细胞的定向分化使其可能成为肝脏细胞移植的一个重要细胞来源,为肝脏疾病的细胞移植治疗奠定基础,在治疗肝脏疾病的研究领域中有着广阔的应用前景。     

胚胎干细胞定向分化为肝脏细胞的研究进展

胚胎干细胞可由哺乳动物的囊胚内细胞群或着床后胚胎组织生殖嵴的原始生殖细胞中分离获得,也可以由核移植克隆技术获得;胚胎干细胞向肝脏细胞的定向分化使其可能成为肝脏细胞移植的一个重要细胞来源,为肝脏疾病的细胞移植治疗奠定基础,在治疗肝脏疾病的研究领域中有着广阔的应用前景.     

生长分化因子5诱导兔脂肪干细胞成软骨细胞分化的实验研究

目的 探讨应用生长分化因子5(growth differentiation factor 5,GDF-5)诱导脂肪干细胞(adipose-deftved stern cells,ADSCs)成软骨细胞分化的可能性及效果. 方法 3月龄清洁级健康日本大耳白兔6只,雌雄不限,体重2～3 kg.取兔皮下脂肪4～6 Ml,采用胶原酶消化离心贴壁培养法培养ADSCs,取第3代细胞进行实验.波形蛋白免疫组织化学和CD44、CD49d、CDl06免疫荧光染色鉴定ADSCs.调整细胞密度为1×106个/Ml,分别用普通细胞培养液以及含0、10、100 ng/Ml GDF.5的软骨细胞诱导液诱导培养.倒置相差显微镜观察细胞形态变化;MTT法检测细胞增殖情况;RT-PCR检测诱导细胞Col Ⅱ和蛋白多糖Mrna的表达;免疫组织化学、阿利新蓝染色、甲苯胺蓝染色和Western blot法检测诱导细胞Col Ⅱ和蛋白多糖表达. 结果 ADSCs呈小圆形、梭形、多角形分布,表面抗原标志CD44、CD49d呈阳性表达,CD106和波形蛋白呈阴性表达.100 ng/Ml GDF-5诱导的ADSCs呈圆形或类圆形,且细胞增殖旺盛.普通培养液和0、10、100 ng/Ml GDF.5成软骨细胞诱导培养后7 d,Col Ⅱ、蛋白多糖Mrna表达均呈浓度依赖性增加,除0、10 ng/Ml GDF-5两组间差异无统计学意义(P>0.05)外,其余各组差异均有统计学意义(P<0.05):100 ng/Ml GDF.5诱导培养14 d,Col Ⅱ、蛋白多糖Mrna以及蛋白表达达高峰,阿利新蓝、甲苯胺蓝染色以及Col Ⅱ免疫组织化学染色均呈阳性. 结论 经一定浓度的GDF-5诱导的ADSCs,Col Ⅱ和蛋白多糖表达明显增加,具有软骨细胞的部分生物学功能.     

人骨髓间充质干细胞向软骨细胞定向分化的研究

目的探讨体外单层培养中诱导人骨髓间充质干细胞(Human Bone Marrow-derived Mesenchymal Stem Cells,hBMSCs)向软骨细胞定向分化的条件.方法采集志愿者骨髓3例,分离培养BMSCs,流式细胞仪分析表面标志.用含TGF-β1的无血清诱导培养基培养7d后,分别行Ⅱ型胶原免疫组化、原位杂交检测,碱性磷酸酶染色,3H标记的胸腺嘧啶脱氧核苷(3H-TdR)掺入实验检测细胞的增殖情况.结果培养的BMSCs表达CD9,而CD34、CD38、CD45、CD61呈阴性.细胞经诱导培养7d后免疫组化、原位杂交可检测到Ⅱ型胶原的表达,碱性磷酸酶染色呈弱阳性,但细胞3H-TdR掺入量低于对照组(P<0.05).结论BMSCs在特定的诱导下能向软骨细胞方向分化,但在无血清培养基中无法有效的增殖.     

干细胞研究的回顾与展望

自 198 1年Evans等[1] 首次成功地从小鼠胚泡内层细胞团中分离出胚胎干细胞以来 ,干细胞的研究已成为生命科学最活跃和最有影响的领域之一。我国国家科技部于 2 0 0 1年批准了 19项国家重点基础研究发展规划资助项目 ,其中有两项为干细胞研究 ,一项是“胚胎生殖嵴干细胞的分化与组织干细胞的可塑性研究” ,首席科学家为北京大学干细胞中心李凌松教授 ;另一项是“干细胞的基础研究与临床应用” ,首席科学家为上海第二医科大学的盛惠珍教授。在同一年度、同一领域批准两项国家重点基础研究发展规划资助项目 ,以往从未有过。2 0 0 1年 6月 ,美…     

羊膜和结膜基质诱导胚胎干细胞分化为上皮样细胞的初步研究

目的观察小鼠胚胎干细胞在保存人羊膜及兔眼表结膜基质上分化的情况。方法36只新西兰兔随机分为3组，每组12只。A组：将表达绿色荧光蛋白（green fluorescent protein，GFP）基因的小鼠ES-GFP细胞用5-溴脱氧尿嘧啶（BrdU）标记后行实验兔结膜下移植；B组：将小鼠ES—GFP细胞接种到人羊膜上共培养4d，用BrdU标记后移植到实验兔结膜缺损区；C组：采用保存羊膜移植到实验兔兔结膜缺损区。分别于移植后1、2、3、4，6和8周，摘取各组实验眼行荧光显微镜、组织学和免疫组织化学检查，荧光检测ES-GFP细胞在组织中的荧光表达，组织学检查移植到结膜基质的ES-GFP细胞的存活、形态变化以及移植局部的反应等情况；免疫组织化学检测移植到结膜基质的带有BrdU标记的ES．GFP细胞CK3／CK12和CK13的表达。结果小鼠ES-GFP细胞接种到人羊膜后能在羊膜上贴附生长，与羊膜共培养4d后部分ES-GFP细胞分化为多角形上皮样细胞，免疫组化显示β1整合素阳性。将负载有ES—GFP细胞的羊膜移植到兔结膜缺损区，术后荧光显微镜可在结膜上皮层检测到绿色荧光带，免疫组织化学检测结膜上皮层CK13表达阳性，CK3／CK12表达阴性，在重建的结膜上皮层可检测到BrdU核阳性细胞，未见异常增殖细胞。结论采用保存人羊膜负载小鼠ES细胞行兔结膜移植，小鼠ES细胞能在兔结膜基质存活并增殖。     

直接贴壁法诱导人胚胎干细胞分化为心肌细胞

摘要：目的利用直接贴壁法体外诱导人胚胎干细胞分化为心肌细胞,并检测其分化效率。方法人胚胎干细胞以1×10’个／cm2的细胞密度传代到铺备有基质胶的培养皿中培养,用带8ng／ml碱性成纤维细胞生长因子（bFGF）的条件培养基培养6d后,更换为RPMI1640．B27培养基,同时加入100ng／ml的人重组activinA处理24h,接着再加入10ng／ml的人重组骨形态发生蛋白4（BMP4）处理4d,之后更换为不带诱导因子的RPMI1640．B27培养基,每隔2～3d换1次培养基,持续2～3周。在光学显微镜下观察记录出现跳动心肌细胞的时间和跳动频率,并计算跳动克隆百分比,24孔板一组,共记录4组96孔;用免疫荧光染色法检测心肌细胞特异标志物心肌肌钙蛋白T（cTnT）;膜片钳实验检测心肌细胞自发性动作电位;跳动心肌细胞经过24h缺氧刺激后,用凋亡试剂盒检测心肌细胞凋亡比例。结果大量的自发跳动心肌细胞在诱导分化13d左右开始出现。分化出现自发跳动心肌细胞的时间为（13．0±1．1）d,百分比为66．7％,跳动频率为（63．0±7．0）次／分;跳动心肌细胞cTnT染色阳性;跳动心肌细胞检测到自发性动作电位;跳动心肌细胞缺氧24h后检测到凋亡比率为8．0％±0．5％。结论国内首次利用直接贴壁法在体外诱导人胚胎干细胞分化为心肌细胞,分化效率达到66．7％,分化时间13d左右。     

转导人端粒酶逆转录酶基因致人骨髓间充质干细胞永生化并向软骨细胞诱导分化的研究

目的 建立永生化人骨髓间充质干细胞系并向软骨细胞诱导分化,以供软骨组织工程基础研究及临床应用.方法 原代培养人骨髓间充质干细胞(hMSC),用含有人端粒酶逆转录酶(hTERT)基因的逆转录病毒转染hMSC,G418筛选得到阳性克隆,体外连续培养,检测端粒酶的表达及活性.TGF-β1和地塞米松对转化后的hMSC-hTERT细胞诱导,使其向软骨细胞分化,并用原位杂交和免疫组化检测II型胶原.结果 外源性hTERT在转染细胞中稳定表达并传至第50代,永生化的hMSC细胞经TGF-β1和地塞米松诱导在体外分化为软骨细胞.结论 外源性hTERT基因可以有效地在体外使hMSC永生化,永生化的hMSC细胞经诱导可在体外分化为软骨细胞,从而作为软骨组织工程研究的细胞来源.     

Differentiation of encapsulated embryonic stem cells after transplantation

BACKGROUND: Embryonic stem cells (ESC) when transplanted into recipients with different major histocompatibility antigens may be rejected, especially as cells differentiate and expression of these antigens increases. One method to prevent rejection is to place the developing ESC in microcapsules. It is currently unknown what effect encapsulation has on the ability of ESC to differentiate. METHODS: Human ESC (hESC; hES03 line) and mouse ESC (mESC; R1 line) were encapsulated in 2.2% barium alginate and transplanted intraperitoneally in SCID and BALB/c mice respectively. Cell morphology, viability, and gene characterization were assessed after retrieving the capsules up to four weeks from SCID mice and three months from BALB/c mice. RESULTS: Encapsulation prevented hESC and mESC from forming teratomas up to four weeks and three months, respectively. mESC but not hESC formed aggregates within the capsules, which remained free of fibrosis. Some but not all the transplanted encapsulated hESC differentiated towards all three lineages, but more so towards an endodermal lineage as shown by increased expression of alpha fetoprotein. This was similar to what occurred when encapsulated and non-encapsulated hESC were cultured in vitro for two weeks. In contrast to the hESC, transplanted encapsulated mESC differentiated mostly towards an ectodermal lineage as shown by increased expression of nestin and glial fibrillary acidic protein. In vitro, encapsulated and nonencapsulated mESC also began to differentiate, but not down any specific lineage. CONCLUSIONS: Encapsulated ESC do differentiate, although along multiple pathways, both when transplanted and maintained in culture, just as nonencapsulated ESC do when removed from their feeder layer.     

Differentiation of embryonic stem cells after transplantation into peritoneal cavity of irradiated mice and expression of specific germ cell genes in pluripotent cells

Permanent embryonic stem cell lines (ES cells) are considered as one of the most promising cellular sources for regenerative medicine. ES cells have a high proliferative potency and ability to differentiate into all kinds of somatic and germ cells. However, transplantation of undifferentiated ES cells into adult recipient tissue results in the formation of teratomas. To understand the mechanisms underlying self-renewal and determination of pluripotent cells, we investigated differentiation potencies of undifferentiated ES cells and differentiating embryoid bodies (EB). ES cells and EBs growing on acetate-cellulose membranes were transplanted into the peritoneal cavity of irradiated mice. Behavior and differentiation of transplanted cells were studied within 1, 2, 3, and 6 weeks after transplantation. No differences in the cell composition were found in the teratomas formed by ES cells and differentiating EBs. The pattern of expression of the genes specific for pluripotent and germ cells was studied in all types of experimental teratomas. The expression of oct4, stella, fragilis was detected in the teratomas, but nanog was not expressed. We conclude that pluripotent cells are retained in the experimental teratomas formed after transplantation of ES cells and EBs but the pattern of expression of the studied genes underwent changes.     

Differentiation of murine embryonic stem cells in skeletal muscles of mice

Possible myogenic differentiation of SSEA-1- and OCT-4-positive murine embryonic stem cells (ESCs) and embryoid bodies (EBs) was studied in vitro and in vivo. In vitro, ESC- or EB-derived ESCs (EBs/ESCs) showed only traces of Pax 3 and 7 expression by immunocytochemistry and Pax 3 expression by immunoblot. By RT-PCR, myogenic determinant molecules (myf5, myoD, and myogenin) were expressed by EBs/ESCs but not by ESCs. However, in such cultures, very rare contracting myotubes were still present. Suspensions of LacZ-labeled ESCs or EBs were injected into anterior tibialis muscles (ATM) of different cohorts of mice for the study of their survival and possible myogenic differentiation. The different cohorts of mice included isogenic adult 129/Sv, nonisogenic CD1 and mdx, as well as mdx immunosuppressed with 2.5 mg/kg daily injections of tacrolimus. Ten to 90 days postinjections, the injected ATM of nonisogenic mice did not contain cells positive for LacZ, SSEA-1, OCT-4, or embryonic myosin heavy chain. The ATM of intact mdx mice contained very rare examples of muscle fibers positive for dystrophin and/or embryonic myosin heavy chain. In the ATM of the isogenic normal and the immunosuppressed mdx mice, as expected, large teratomas developed containing the usual diverse cell types. In some teratomas of immunosuppressed mdx mice, small pockets of muscle fibers expressed dystrophin and myosin heavy chain. Our studies indicated that in muscles of animals nonisogenic with the used ESCs, only very rare ESCs survived with myogenic differentiation. These studies also indicated that ESCs will not undergo significant, selective, and preferential myogenic differentiation in vitro or in vivo in any of the models studied. It is probable that this strain of murine ESC requires some experimentally induced alteration of its gene expression profile to secure significant myogenicity and suppress tumorogenicity.     

小鼠胎肝干细胞抗原阳性细胞移植后向神经组织细胞分化

目的了解小鼠胎肝干细胞是否具有向神经组织细胞分化的潜能。方法　采用免疫磁珠法分离雄性胎鼠肝脏的千细胞抗原1阳性(Sca-1 )细胞;将8-10周的C57BL/6J雌性小鼠用致死剂量(10.0Gy)放射线照射,然后尾静脉注射Sca-1 细胞2.0×103。Sca-1 细胞移植后2、4、6个月后,将受者脑组织作免疫组织化学和FISH双染色检测。结果移植后雌性受鼠脑组织内存在大量Y染色体阳性细胞;统计比较移植后2、4、6个月时,受者脑组织中Y染色体阳性细胞百分数无明显差别。免疫组织化学分析显示,这些Y染色体阳性细胞表达神经组织细胞特异标志,如神经元核特异蛋白(Neu N)、神经纤维细丝蛋白(NF-M)、微管蛋白Ⅲ(TuJ-1)或者胶质纤维酸性蛋白(GFAP) 等。Y染色体阳性细胞约占脑组织总细胞数的(4.5±0.5)%.其中Y染色体和Neu N均阳性的细胞为(1.2±0.3)%、Y染色体和GFAP均阳性的细胞为(1.0±0.2)%。结论经尾静脉移植小鼠胎肝Sca 1 细胞能迁移进入经致死剂量全身照射的雌性小鼠脑组织,并且能分化成神经组织细胞,且能长期存活(存活至少6个月以上)。这为神经组织细胞发育分化机制研究和神经系统疾病的治疗提供了理论依据和研究材料     

骨髓间充质干细胞定向肝细胞样分化的研究

目的探讨骨髓间充质干细胞定向肝细胞样分化的诱导条件，为肝组织工程提供新的种子细胞来源。方法分离小鼠骨髓间充质干细胞，在特定肝细胞培养液中用肝细胞生长因子(HGF)和表皮细胞生长因子(EGF)定向诱导。在倒置显微镜下观察细胞形态。应用免疫荧光法鉴定细胞性质。结果骨髓间充质干细胞经HGF和EGF诱导7d后变为肝细胞样圆形；2周后免疫荧光染色可见分化后细胞表达肝细胞标志物CK18和白蛋白。结论骨髓间充质干细胞在特定条件诱导下可以向肝细胞方向分化。有可能作为肝组织工程的种子细胞来源。     

Differentiation of human embryonic stem cells on periodontal ligament fibroblasts in vitro

Abstract:  Human embryonic stem cells (hESCs) are pluripotent cells with unlimited proliferation potential and differentiation capacity to all types of somatic cells. Periodontal tissue engineering based on in vitro expanded cells holds the promise to overcome the limitations associated with contemporary regenerative techniques. The aim of this study was to investigate the differentiation patterns of hESCs under the influence of periodontal ligament cells in vitro. hESCs (HUES-9) were expanded and characterized for their pluripotency. Then they were transfected with green fluorescent protein-carrying plasmid, and cocultured with human periodontal ligament fibroblastic cells for 21 days. Two experimental groups were established with different medium constituents. Specimens were fixed at days 7, 14, and 21 and were analyzed morphologically under inverted light microscope, and by immunohistochemistry using antibodies against collagen types I and III, fibronectin, fibroblast surface protein, vimentin, and pancytokeratin. Our results demonstrate different patterns of cell differentiation between groups, with about one-fifth of cells in colonies acquiring characteristics similar to periodontal ligament fibroblastic progenitors while others proceed toward distinctive lineages. This indicates the feasibility to direct the differentiation of hESCs toward the periodontal ligament fibroblastic progenitors to some extent. These findings support the notion that hESCs may become a cell source with unlimited supply for periodontal tissue engineering applications.     

Differentiation of human and mouse embryonic stem cells along a hepatocyte lineage

Embryonic stem (ES) cells may differentiate along a hepatocyte lineage; however, currently there are no reports of culture conditions yielding high levels of hepatocyte-specific gene expression in these cells. We investigated culture conditions for differentiating ES cells into hepatocyte-like cells in vitro. Various combinations of culture media, growth and differentiation factors, and substratum precoatings were evaluated, and it was determined that a combination of Iscove's modified Dulbecco's medium with 20% fetal bovine serum, human insulin, dexamethasone. and collagen type I precoating was optimal for directing mouse ES cells along a hepatocyte lineage. Treatment of mouse ES cell with the optimal condition led to prealbumin gene expression 20% as high, and albumin synthesis 7% as high, as in mouse liver. The optimal culture condition also induced albumin gene expression in differentiated human ES cells 1% as high as in normal human hepatocytes as shown by Western blot analysis, and cells were positive for human albumin by immunocytochemistry. In addition, our optimal condition led to high levels of albumin gene expression in primary mouse hepatocytes after 35 days of culture, levels 10-fold higher than with other hepatocyte differentiation media. In conclusion, our optimal condition directed both mouse and human ES cells along a hepatocyte lineage. This represents the initial step in establishing cell lines that can be employed in cell-based therapeutics in humans and for toxicology and pharmacology studies.     

罗氏易位伴少弱精子症来源的胚胎干细胞向生殖细胞诱导分化的研究

目的:建立罗氏易位伴少弱精子症来源的人胚胎干细胞(ESC),利用体外诱导ESC向生殖细胞分化作为模型,评估辅助生殖技术子代的潜在风险。方法:利用罗氏易位伴少弱精子症患者夫妇捐赠的胚胎,通过分离囊胚内细胞团,培养、传代、扩增,建立ESC CCRM16,其核型为46,XY,+14,rob(13;14)(q10;q10);添加2 mol/L维甲酸体外诱导分化,分析其向生殖细胞分化过程及其相关基因的表达,并与遗传背景完全正常的ESC CCRM23相比较。结果:CCRM16表达OCT4,TRA-1-81,NANOG及SSEA4多能性标记基因,体外能形成拟胚体(EB),体内、体外都能向3个胚层分化。添加维甲酸可直接诱导ESC向生殖细胞分化。原始生殖细胞标志基因DAZL和减数分裂标记基因SCP3的表达水平在CCRM16中较正常夫妇捐赠胚胎建立的ESC CCRM23明显减少。结论:核型为46,XY,+14,rob(13;14)(q10;q10)CCRM16具有ESC典型特征,但其向早期精子分化的过程异常。体外诱导CCRM16向精子分化作为研究模型,可应用于评估少弱精子症患者辅助生殖出生子代的健康风险。     

睾丸间质干细胞分化和移植

睾丸间质细胞是男性体内合成雄激素的主要细胞,胚胎发育期中肾胚的间质细胞及生精小管周成纤维样细胞可能是睾丸间质细胞的干细胞。在胚胎期间质干细胞分化为胎儿型间质细胞;出生后间质干细胞经间质祖细胞、未成熟间质细胞分化为成熟间质细胞。老年期间质细胞数量可能不变,但雄激素合成下降。间充质干细胞及脂肪干细胞等干细胞经诱导可分化为分泌雄激素的睾丸间质细胞,因此,间质干细胞移植可望成为治疗男性性腺功能不全和中老年雄激素缺乏的创新方法,本文对睾丸间质干细胞的分化及移植方面研究进行综述。