大鼠骨髓间充质干细胞的PKH26标记和示踪☆

背景：骨髓间充质干细胞标记是体内迁移分化研究的重要环节。 目的：对大鼠骨髓间充质干细胞进行PKH26标记,探讨PKH26标记对骨髓间充质干细胞的生长特征、分化的影响及体内示踪情况。 方法：培养扩增大鼠骨髓间充质干细胞,第2代细胞按PKH26标记程序进行细胞标记,观察标记组和未标记组细胞的增殖、周期和凋亡情况,对标记组细胞行成骨成脂体外诱导分化。尾静脉移植PKH26标记细胞,6周后荧光显微镜观察骨髓间充质干细胞在子宫内膜的分布情况。 结果与结论：PKH26标记对细胞增殖、凋亡和周期无明显影响,不影响成骨成脂诱导分化。子宫内膜组织中PKH26标记阳性的细胞分布于腺上皮和间质细胞。PKH26标记技术可用于示踪骨髓间充质迁移转归和干细胞移植方面的实验研究。      

全骨髓法体外培养分离大鼠骨髓间充质干细胞及PKH26标记

背景：要获得动物实验需要的标记大鼠骨髓间充质干细胞,体外培养、扩增和示踪已成为实验的关键环节。 目的：采用全骨髓培养分离大鼠骨髓间充质干细胞,以及PKH26对其体外标记,建立一种方便、实用的分离培养并示踪骨髓间充质干细胞的方法。 方法：通过全骨髓培养分离法纯化大鼠骨髓间充质干细胞。经传代扩增,细胞进一步纯化。取第3代大鼠骨髓间充质干细胞按PKH26标记程序进行标记后培养,荧光显微镜下观察标记后细胞生长状态、萤光强度变化和传代培养效果。利用四唑盐比色法测定标记后骨髓间充质干细胞的生长曲线。 结果与结论：全骨髓培养分离法能成功获得纯度高的骨髓间充质干细胞,用PKH26标记后的骨髓间充质干细胞呈红色荧光,体外连续传代培养3代后,细胞荧光强度逐渐减弱。PKH26标记骨髓间充质干细胞的生长形态、生长活力不发生改变。结果证实全骨髓培养分离法简便易行,能获取较高纯度的生长增殖状态良好的骨髓间充质干细胞,PKH26荧光标记大鼠骨髓间充质干细胞是一种有效、实用的方法。     

流动优化骨髓间充质干细胞的分化状况

背景：间充质干细胞在成体动物骨髓中含量极低。 目的：观察成年大鼠骨髓间充质干细胞经生理范围流动切应力作用后,其体外生长规律、增殖及定向分化为成骨细胞及脂肪细胞的能力。 方法：在体外取得SD大鼠骨髓原代间充质干细胞,利用平板流室系统加载1 Pa切应力,对其进行培养及扩增,并分别向成骨细胞及脂肪细胞定向诱导。 结果与结论：原代间充质干细胞为长梭形或多角形,集落样生长;经流动加载并传代后细胞生长速度加快,不以集落方式生长,而是均匀分布。细胞体积明显增大,多数为长梭形或多角形;生长曲线显示各代细胞有类似的生长规律;激光共聚焦显微镜显示CD44和CD90阳性,CD31及CD45阴性;向成骨细胞及脂肪细胞诱导14 d后,Von Kossa染色及油红O染色均为阳性,流动优化后骨髓间充质干细胞保持了体外大量增殖及多向分化潜能。     

人脐静脉来源的间质干细胞体外分离扩增及多向分化的研究

目的： 探讨人脐静脉来源的间质干细胞(MSCs) 的体外分离、纯化、扩增和多向分化条件。 方法： 无菌条件下取正常人脐静脉,1%胶原酶Ⅱ消化脐静脉细胞，以IMDM作为培养基进行培养和纯化细胞，瑞氏染色和电镜观察形态；FACS检测其免疫表型和细胞周期；体外诱导成骨细胞、脂肪细胞分化，von Kossa染色、油红O染色和RT-PCR检测骨钙蛋白、脂蛋白脂酶mRNA的表达以检测细胞向成骨、成脂肪细胞分化情况。 结果： 脐静脉来源的细胞呈纤维样贴壁生长，瑞氏染色和电镜观察具有MSCs特征；FACS检测结果显示, 表达MSCs相关的抗原CD29、CD44、CD105，而CD31、CD13、CD34、CD45、HLA-DR为阴性；体外诱导成骨细胞、脂肪细胞分化成功。 结论： 人脐静脉来源的MSCs的细胞形态、生长特性、免疫表型、多向分化能力与骨髓来源的MSCs相似，可作为满足实验和临床需要的MSCs来源。     

人骨髓间充质干细胞接种纳米晶胶原骨构建组织工程骨

目的观察体外培养的人骨髓间充质干细胞（mesenchymal stem cells,MSCs）与纳米晶羟基磷灰石/胶原骨（nano-hydroxyapatite/collagen,nHAC）的生物相容性及细胞在nHAC上的生长情况。方法全骨髓法体外培养骨髓间充质干细胞,应用成骨诱导剂诱导向成骨细胞表型转化,通过细胞活性、免疫组化鉴定诱导培养的成骨细胞的细胞学特性。通过倒置显微镜、扫描电镜观察细胞生长及其在nHAC上的生长情况。结果原代培养的骨髓细胞增殖迅速,10～12d左右即可稳定传代,传代细胞7～9d即可传代。经诱导培养的细胞的ALP染色阳性,Von Kossa染色阳性,可见钙化的基质沉积,呈现典型的成骨细胞形态和生物学特征。构建的MSCs与nHAC共培养的模型中,细胞可在nHAC表面良好贴壁。复合培养8天,分布于支架材料上的细胞大量增殖、分泌细胞外基质。第14天,大量细胞在材料表面和孔隙中生长。细胞之间广泛存在突起连接。结论nHAC适合种子细胞的贴附、生长和增殖,是组织工程良好的载体材料。     

大鼠真皮间充质干细胞的体外长期培养及胶原海绵对其生长的影响

从新生大鼠真皮细胞中分离多能干细胞，体外长期传代培养，观察细胞形态和超微结构的变化。检测细胞增殖和分化能力的改变及胶原基质对细胞生长的影响。揭示体外长期传代培养对大鼠真皮间充质干细胞生物学性状的影响，结果表明；大鼠真皮组织中的间充质干细胞体外培养至180d，传至25代的细胞仍具有干细胞的特征；形态的均一，细胞核结构原始，细胞器不发达；体外增殖迅速，保持了向成骨细胞和软骨细胞分化的潜能，胶原基质成分可促进细胞的生长，而胶原海绵支架更利于细胞的三维生长。结论是体外长期传代培养后大鼠真皮间充质干细胞仍保持良好的干细胞特性，为真皮间充质干细胞的深入研究与应用提供了实验依据。     

成年大鼠和恒河猴骨髓基质干细胞的体外培养及鉴定

本实验目的是比较成年大鼠和恒河猴骨髓基质干细胞(MSCs)原代培养的细胞形态和生长状况的差异。分别分离成年大鼠和恒河猴的骨髓,密度梯度离心法分离MSCs,传代培养。在细胞生长过程中显微镜观察两种细胞形态及生长状况的差异,并分别进行成脂及成骨诱导。结果表明,在相同的培养条件下,成年大鼠和恒河猴MSCs原代培养细胞形态比较接近,但细胞原代及传代生长状况有差异。大鼠MSCs原代培养及细胞冻存后复苏的生长均快于猴的MSCs。两种动物的细胞都可以向脂肪和成骨细胞分化。猴的MSCs因其生长缓慢和细胞形态的明显改变,需改良其培养条件,才能用于进一步的研究。     

定向诱导大鼠骨髓间充质干细胞分化为成骨细胞

目的建立体外定向诱导大鼠骨髓间充质干细胞（MSCs）分化为成骨细胞的模型,为将MSC3用作骨组织工程的种子细胞奠定基础。方法用成骨添加剂（地塞米松10^-8mol/L、β-甘油磷酸钠10mmol／L、维生素C50mg/L）定向诱导传代大鼠骨髓MSCs分化为成骨细胞,通过形态学、生长曲线、免疫细胞化学及碱性磷酸酶染色鉴定成骨细胞。结果诱导组具有成骨细胞的形态和生长特点,增殖相对缓慢,但与对照组间的差异没有统计学意义（P〉0．05）,碱性磷酸酶活性增强。结论建立了体外定向诱导大鼠骨髓MSCs向成骨细胞转化的模型,成骨添加剂不影响细胞的增殖,可迅速大量获得种子细胞。     

人骨髓间质干细胞体外扩增和向成骨细胞分化的实验研究

骨髓间质干细胞（mesenchymal stem cell,MSCs）是一类存在于骨髓中的具有多向分化潜能的干细胞，在体外不仅可分化为间质类细胞，而且可以分化为非间质细胞。本研究探讨人骨髓间质干细胞的体外分离纯化、培养扩增和向成骨细胞诱导分化的条件。利用密度为1．073g/ml的Percoll分离骨髓的单个核细胞，以含10％胎牛血清的低糖DMEM培养基培养与扩增MSCs，细胞纯度可达95％左右。取第二代和第三代的MSCs，以含有不同浓度的抗坏血酸、β－磷酸甘油、地塞米松的诱导培养基向成骨细胞诱导，诱导向的细胞呈现典型的成骨细胞样改变，免疫组化技术显示其I型胶原染色阳性，ALP染色阳性，表明MSCs在体外具有向成骨细胞分化的潜力。     

全骨髓贴壁法培养兔骨髓间充质干细胞体外定向成骨诱导分化及鉴定

背景：流式细胞仪分离法和免疫磁珠分离法对细胞活性影响较大,密度梯度离心法虽然能够获得纯度高的单核细胞,但由于多次离心可造成细胞的大量流失且对细胞活性有一定的影响使其应用值得商榷。 目的：采用全骨髓贴壁法分离兔骨髓间充质干细胞进行成骨诱导分化及鉴定。 方法：采用全骨髓贴壁法体外分离培养兔骨髓间充质干细胞,倒置显微镜下观察细胞形态学特征。在成骨诱导剂作用下,通过碱性磷酸酶染色试剂盒行碱性磷酸酶染色,Ⅰ型胶原免疫细胞化学染色,Von Kossa法及茜素红进行矿化结节染色以及电镜下检测兔骨髓间充质干细胞成骨诱导后的形态结构。 结果与结论：经诱导后细胞出现与成骨细胞相似的形态学特征,碱性磷酸酶染色阳性,Ⅰ型胶原免疫细胞化学染色,Von-Kossa法及茜素红矿化结节染色阳性。表明经成骨诱导剂诱导后全骨髓贴壁法体外分离纯化培养的兔骨髓间充质干细胞能向成骨细胞方向分化增殖。     

Cloning of the nucleostemin gene and its function in transforming human embryonic bone marrow mesenchymal stem cells into F6 tumor cells

We recently established a novel tumor cell line denominated as F6, which was derived from mutated human embryonic bone marrow mesenchymal stem cells (MSCs). The difference between gene expression of F6 cells and MSCs was distinguished by fluorescent differential display. Results showed that the expression of nucleostemin, a novel factor participating in the control of stem and cancer cell proliferation, was different in F6 cells and MSCs. To further understand its role in transforming human embryonic bone marrow mesenchymal stem cells into F6 tumor cells, the full-length nucleostemin gene (1650 bp) from an LTEP-a-2 cell line was cloned, and GST-nucleostemin protein was expressed in E. coli. The characteristics of nucleostemin expression in F6 cells and other human cancer cell lines were investigated by RT-PCR, Western blot analysis, immunocytochemical staining, fluorescent microscope and confocal laser scanning microscope. The levels of nucleostemin gene expression were detected by real-time PCR in F6 tumor tissue obtained from SCID nude mice at 4, 6 and 7 weeks after the injection of F6 cells, and from the lung tissue of five lung cancer patients. Results showed that nucleostemin gene expression increased significantly in F6 tumor tissue and lung cancer tissue. The results also showed that transfection with pcDNA3.1(+)-GFP-nucleostemin for 4-20 weeks promoted cell size augmentation and nuclei multiplication, and the cells were converted to giant cell-like cells. Western blot analysis revealed that expression levels of nucleostemin in the nuclei and cytoplasm of cancer cell lines, e.g. F6, LTEP-a-2, U937, SW480 and 95D, were higher than those in MSCs and COS-7 cells. Levels of nucleostemin in F6 cells were notably high and confirmed with immunohistochemical staining. These results implied that nucleostemin may play an important role in both tumorigenesis and transforming human embryonic bone marrow mesenchymal stem cells into F6 tumor cells.     

Ex Vivo PKH26-Labelling of Lymphocytes for Studies of Cell Migration In Vivo

A prerequisite for studies of cell migration is that the cells of interest can be appropriately labelled and subsequently easily traced. The use of radioisotopes or fluorescent substances that bind covalently to the cell surface, e.g. fluorescein isothiocyanate (FITC) or rhodamine isothiocyanate (RITC), have limitations such as rapid loss of the labelling, toxicity and interference with cell surface molecules. In the present work the authors labelled rat spleen lymphocytes with the fluorescent labelling molecule PKH26, which is incorporated into the lipid bilayer of cytoplasmic membranes. The labelled lymphocytes were injected intravenously into syngeneic recipients and 2 or 6 days later the lymphocytes were detected in various organs by using flow cytometry and fluorescence microscopy. As could be expected, the lymphocytes homed to lymphoid tissues, preferably the spleen, and no labelled cells were found in non-lymphoid organs such as the heart and the kidney. Membrane labelling proved to be intense, uniform and stable and PKH26 positive cells were easily detectable in fractions less than 0.2% in peripheral blood and the various tissues after 6 days of in vivo circulation. Thus, the PKH26 dye appears to be suitable for labelling cell populations used in the study of cell migration in vivo , both under normal conditions and when specific immunological processes are taking place, such as graft rejection and tumour growth.     

新型壳聚糖基仿生网络复合膜诱导骨髓间充质干细胞定向成骨分化

目的 探讨新型壳聚糖基网络复合膜诱导骨髓间充质干细胞（MSCs）定向成骨分化的可行性.方法 采用仿生学方法,壳聚糖、明胶、果胶按照一定比例制作成新型壳聚糖基仿生网络复合膜.设计4个组：实验组1（复合膜＋常规培养基）,对照组1（常规培养基）,实验组2（复合膜＋成骨诱导（OS）培养基）,对照组2（OS培养基）.通过倒置相差显微镜、四甲基偶氮唑盐（MTT）法、扫描电镜（SEM）检测细胞在复合膜上的生长和增殖情况;通过测定碱性磷酸酶（ALP）活性来评价MSCs在复合膜上的成骨分化能力;通过特殊染色和能谱分析（EDX）来评定钙盐的沉积.结果 MSCs在网络复合膜上贴附、生长良好且增殖旺盛.MTr法检测细胞活力显示实验组吸光度（OD）值与对照组比较无统计学意义（P＞0.05）.SEM观察到细胞在支架材料表面呈聚集生长,分泌大量的细胞外基质,可见散在的结节形成.实验组1的ALP活性明显增高,与实验组2、对照组比较有统计学意义（P＜0.01）.茜素红和Von Kossa染色可见实验组细胞分化后形成的钙化结节;ALP染色可见胞浆内蓝染颗粒;EDX检测到Ca、P沉积.结论 新型壳聚糖基网络复合材料具有良好的生物相容性,在不添加诱导剂的条件下,可以诱导MSCs定向成骨分化.     

Osteoinductivity of partially purified bovine, ostrich and emu bone morphogenetic proteins in vitro

The aim of this study was to observe the osteogenic activity of native bone morphogenetic proteins (BMPs) obtained from different species including bovine, ostrich and emu sources in order to compare mammalian and avian BMPs. Rat mesenchymal progenitor marrow stromal cells and pre-osteoblastic C2C12 cell cultures, were exposed to the native BMPs and alkaline phosphatase (ALP) and creatine kinase (CK) levels were determined by assay. The results showed that the ALP activity in C2C12 cultures was elevated by bovine BMP by 2- to 10-fold (p < 0.05-0.001) from day 3 during 14 days. There were no significant differences in avian BMP related elevations of ALP activity except with ostrich BMPs at day 14 (p < 0.05). However, exposure of MSCs cultures to BMPs derived from bovine, ostrich or emu sources resulted in elevated ALP from day 3 (p < 0.05). Bovine BMP resulted in more ALP elevation than with either of the avian BMPs. All of BMPs elevated Creatine kinase (CK) activity from day 1 and climbed until peaking at day 7. Compared with control cultures, CK was elevated more with exposure to emu BMP and was more elevated with greater statistical significance than with bovine and ostrich BMP before day 5. These higher levels remained until day 14 (p < 0.05). The results of this study suggest that both bovine and avian BMPs are able to stimulate osteogenesis in mature osteoblasts in vitro. The strongest synergistic effect on osteogenesis was detected in cells stimulated with bovine BMP. Avian BMPs had lower effects on ALP and CK activity, emu BMP being more effective than ostrich BMP.     

神经生长因子转染骨髓间充质干细胞诱导分化成神经样细胞

目的探讨神经生长因子(NGF)转染大鼠骨髓间充质干细胞(MSCs)后的表达及其对MSCs分化成神经样细胞的影响。方法在体外低密度扩增大鼠骨髓MSCs。应用基因重组技术,构建pEGFP-NGF真核表达质粒,并将其转染至MSCs中。免疫荧光标记法检测中间神经丝蛋白(NF-M)和胶质纤维酸性蛋白(GFAP)的表达。在荧光显微镜下观察MSCs阳性荧光的表达率、细胞的形态变化和类型。结果MSCs阳性荧光的表达率约为30%。转染后,MSCs呈现多突起,且几个突起之间互相连接成网状,似神经元样的形态。免疫荧光标记法鉴定其中一部分细胞表达NF-M,另一部分细胞表达GFAP。结论转染的MSCs可表达NGF并在含有NGF的微环境中分化成神经样细胞。     

Double labelling of human umbilical cord mesenchymal stem cells with Gd‐DTPA and PKH26 and the influence on biological characteristics of hUCMSCs

The aim of this study was to determine whether double labelling of human umbilical cord mesenchymal stem cells (hUCMSCs) with gadolinium‐diethylene triamine penta‐acetic acid (Gd‐DTPA) and PKH26 influences their biological characteristics. A tissue adherence technique was used to separate and purify the hUCMSCs and flow cytometry was performed to detect the surface markers expressed on them. Gd‐DTPA and PKH26 were used to label the stem cells and MRI and fluorescence microscopy were used to detect the double‐labelled hUCMSCs. A MTT assay was used to delineate the growth curve. Transmission electron microscopy (TEM) and atomic force microscopy were used to demonstrate the ultrastructural features of the hUCMSCs. Flow cytometry showed that hUCMSCs highly expressed CD29, CD90, CD44 and CD105. No expression of CD31, CD34 and CD45 was detected. Very low expression of HLA‐DR and CD40 was detected. Atomic force microscopy showed these cells were long, spindle shaped, and the cytoplasm and nucleus had clear boundaries. After double labelling, TEM showed Gd particles aggregated in the cytoplasm in a cluster pattern. The proliferation activity, cell cycle, apoptosis and differentiation of the stem cells were not influenced by double labelling. Thus a tissue adherence technique is helpful to separate and purify hUCMSCs effectively; and Gd‐DTPA and PKH26 are promising tracers in the investigation of migration and distribution of hUCMSCs in vivo.     

微弧氧化陶瓷膜表面骨髓间充质干细胞生物相容性实验

目的观察微弧氧化（micro-arc,MAO）陶瓷膜表面骨髓间充质干细胞（mesenchymal stem cell,MSC）的黏附和增殖生长情况,通过MSC在三组不同表面处理材料表面的黏附和增殖情况评价微弧氧化陶瓷膜表面的生物相容性。方法贴壁法培养大鼠骨髓间充质干细胞,骨诱导培养后,做碱性磷酸酶染色和茜素红钙结节染色,鉴定其成骨潜能。取生长良好的第三代MSC,调整细胞密度为5×10^4/mL,接种到三组钛片表面。在接种细胞后第1、3、5、7天每组分别取出5枚钛片,一个做电镜扫描,另外4个细胞计数。观察MSC在不同材料表面的黏附增殖情况。电镜扫描MAO陶瓷膜表面形貌特征,EDX分析其表面主要元素含量。结果MSC具有良好的成骨特性,在MAO陶瓷膜表面的增殖优于光滑组和喷沙组。电镜下微弧氧化陶瓷膜表面有无数2～10m的微孔,并含有钙、磷成分。结论MAO陶瓷膜具有良好的生物相容性,大鼠骨髓间充质干细胞在其多孔,含有钙、磷元素表面的黏附及增殖均优于其它组。     

Utilization of transgenic models in the evaluation of osteogenic differentiation of embryonic stem cells

Abstract

Previous studies reported that embryonic stem cells (ESCs) can be induced to differentiate into cells showing a mature osteoblastic phenotype by culturing them under osteo-inductive conditions. It is probable that osteogenic differentiation requires that ESCs undergo differentiation through an intermediary step involving a mesenchymal lineage precursor. Based on our previous studies indicating that adult mesenchymal progenitor cells express α-smooth muscle actin (αSMA), we have generated ESCs from transgenic mice in which an αSMA promoter directs the expression of red fluorescent protein (RFP) to mesenchymal progenitor cells. To track the transition of ESC-derived MSCs into mature osteoblasts, we have utilized a bone-specific fragment of rat type I collagen promoter driving green fluorescent protein (Col2.3GFP). Following osteogenic induction in ESCs, we have observed expression of alkaline phosphatase (ALP) and subsequent mineralization as detected by von Kossa staining. After 1 week of osteogenic induction, ESCs begin to express αSMARFP. This expression was localized to the peripheral area encircling a typical ESC colony. Nevertheless, these αSMARFP positive cells did not show activation of the Col2.3GFP promoter, even after 7 weeks of osteogenic differentiation in vitro. In contrast, Col2.3GFP expression was detected in vivo, in mineralized areas following teratoma formation. Our results indicate that detection of ALP activity and mineralization of ESCs cultured under osteogenic conditions is not sufficient to demonstrate osteogenic maturation. Our study indicates the utility of the promoter-visual transgene approach to assess the commitment and differentiation of ESCs into the osteoblast lineage.     

放射抑制小鼠骨髓间充质干细胞成骨潜能并导致骨损伤

目的 观察放射对小鼠骨髓间充质干细胞(BMMSCs)体外成骨潜能及体内骨组织的影响.方法 分离、培养正常的及接受4Gy放射后28d的小鼠BMMSCs,用碱性磷酸酶(ALP)和Von Kossa染色法鉴定BMMSCs体外成骨分化潜能的改变,并通过骨组织形态学和骨密度(BMD)检测放射后小鼠体内骨组织的相关变化.结果 4Gy照射28d后小鼠BMMSCs的成骨潜能明显降低,同时体内骨组织结构破坏,小鼠骨密度降低.结论 放射损伤后小鼠BMMSCs的成骨潜能显著降低,可能在干细胞水平参与了放射后骨损伤的发生.