骨髓间充质干细胞成肌和成脂分化的调控

骨髓间充质干细胞(mesenchymal stem cells,MSCs)是来源于骨髓基质的一类具有高度自我更新能力和多向分化潜能的成体干细胞.因其具有容易获取、体外扩增方便迅速、移植排斥反应较弱等优点而成为临床应用的理想细胞模型.骨髓间充质干细胞向成肌和成脂的分化对动物机体内肌肉和脂肪的组成具有直接影响,因而与肉品质及人类健康息息相关.本文综述了骨髓间充质干细胞定向分化为骨骼肌细胞和脂肪细胞的过程及其调控机制,并重点分析了关键调控因子PRDM16(PR domain-containing16)和骨形态发生蛋白(bone morphogenetic proteins,BMPs)在骨髓间充质干细胞成肌和成脂分化中的作用.     

3种间充质干细胞成软骨分化潜能比较

目的:比较骨髓间充质干细胞、脂肪间充质干细胞、滑膜间充质干细胞3种间充质干细胞的成软骨分化潜能,为软骨组织工程中种子细胞的选择提供实验依据。方法:采用贴壁法分别分离提取兔骨髓间充质干细胞、脂肪间充质干细胞、滑膜间充质干细胞3种间充质干细胞,并进行传代培养,绘制3种间充质干细胞的生长曲线并比较其倍增时间。将3种间充质干细胞成软骨诱导14 d后,行甲苯胺蓝染色及II型胶原免疫组化染色以观测3种细胞成软骨分化能力。结果:脂肪间充质干细胞的倍增时间短于骨髓间充质干细胞,滑膜间充质干细胞的倍增时间最短;3种细胞成软骨诱导14 d后均产生糖胺聚糖和II型胶原,且组与组之间II型胶原表达水平的差异有统计学意义,骨髓间充质干细胞组高于脂肪间充质干细胞组(P0.01),滑膜间充质干细胞组高于骨髓间充质干细胞组(P0.01)。结论:在一定的培养条件下,3种间充质干细胞均有一定的成软骨细胞分化潜能,滑膜间充质干细胞最快的增殖速度及最强的成软骨分化潜能。     

DDR2基因缺失对小鼠骨髓间充质干细胞生物学特性的影响

目的:骨髓间充质干细胞(Bone Mesenchymal Stem Cells,BMSCs)是骨再生工程中重要的种子细胞,它对骨组织缺损的修复有着良好的效果。但是BMSCs向成骨细胞分化并修复骨组织缺损是是由细胞外因子共同作用产生的结果。DDR2(Discoidin Domain Receptor 2)作为I型胶原的特异性受体在成骨细胞的分化中发挥重要的调节作用。而对于其在BMSCs向成骨细胞的分化过程中的所起到的作用还鲜有研究,对其作用机理尚不明确。因此我们希望通过分离、培养并鉴定比较DDR2基因缺失小鼠与野生型小鼠来源的骨髓间充质干细胞了解其生物学特性,为后续的实验奠定理论基础。方法:采用改良型的全骨髓贴壁细胞分离方法分离培养两种小鼠来源的骨髓间充质干细胞,采用流式细胞技术鉴定其表面标记物的表达,并利用诱导培养液诱导骨髓间充质干细胞向成骨细胞和成脂肪细胞分化。结果:分离培养的两种骨髓间充质干细胞形态一致,增殖能力和自我更新能力强,流式细胞术检测其表面标记物CD29,Sca-1均表达阳性,CD105,CD45表达为阴性,分离得到的两种细胞均有向成骨细胞和成脂肪细胞分化的能力,但可以明显观察到DDR2基因缺失小鼠的骨髓间充质干细胞的成骨分化能力减弱。结论:本实验通过对于DDR2基因缺失小鼠BMSCs分离、培养和鉴定,初步探索DDR2基因缺失在在成骨过程中的作用结果,为进一步研究提高BMSCs的成骨分化能力奠定理论基础。经实验证明,DDR2基因缺失小鼠来源的骨髓间充质干细胞虽然仍具备干细胞的生物学特性,但其向成骨细胞的分化能力明显减弱,说明DDR2基因缺失对其骨髓间充质干细胞的成骨分化等有着重要的影响。     

胎儿肺脏来源间充质干细胞的鉴定与损伤修复的实验研究

目的 :为研究胎儿肺脏来源间充质干细胞的生物学性状 ,表型和多向分化能力。方法 :取胎龄为 4～ 5个月水囊引产胎儿 ,将肺脏细胞在SF(含 2 %FBS)培养基中培养。测定生长曲线、利用流式细胞仪对培养细胞进行表型测定 ,细胞周期分析 ,体外诱导分化实验。NOD SCID鼠放射损伤后 ,尾静脉输入经PKH2 6染色的间充质干细胞 ,两个月后检测外源细胞在肺脏的定植情况。结果 :从胎儿肺脏可培养出间充质干细胞 ,并可诱导成骨、软骨和脂肪细胞分化 ;移植两个月后可以检测到外源细胞在肺脏的定植。结论 :从胎儿肺脏可分离培养出间充质干细胞 ,在体外有效扩增且保持其低分化状态 ;间充质干细胞可以在肺脏长时间定植。     

黄精多糖对小鼠骨髓间充质干细胞向成骨细胞分化中PINP和BMP-2表达的影响

探讨黄精多糖(PSP)对小鼠骨髓间充质干细胞向成骨细胞分化作用中I型前胶原N端前肽(Procollagen typeⅠN-terminal Propeptide,PINP)和骨形态发生蛋白2(Bone morphogenetic protein-2,BMP-2)表达的影响。取8周龄雄性BALB/C小鼠1只,无菌操作分离小鼠股骨和胫骨,注射器冲出骨髓制成细胞悬液,传代3次后分为6组用于实验。空白诱导组仅加入等量成骨诱导培养基;阳性对照诱导组加入等量成骨诱导培养基及雌二醇(10-8mol/L);各PSP诱导组:加成骨诱导培养基和各自浓度的PSP(200、300、400、500 mg/mL)。每天在倒置显微镜下观察各组细胞的生长情况及形态变化。倒置相差显微镜镜下观察细胞形态变化。在培养第7 d、第14 d采用ELISA酶联免疫吸附法分别测量细胞PINP和BMP-2的表达量。实验结果显示小鼠骨髓间充质干细胞原代培养呈长梭形,有接触抑制现象,诱导后细胞呈三角形、多角形、不规则形状,细胞生长密集时可重叠生长。各不同浓度PSP诱导组均比非诱导组高表达PINP和BMP-2(P0.01)。表明PSP呈剂量相关性促进体外培养的小鼠骨髓间充质干细胞成骨分化,高浓度PSP可显著促进骨髓间充质干细胞骨向分化过程中BMP-2和PINP的表达。     

脱细胞神经移植物对骨髓间充质干细胞的诱导分化

目的探讨脱细胞神经移植物诱导大鼠骨髓间充质干细胞分化为施旺细胞样细胞的可行性。方法将分离纯化的SD大鼠骨髓间充质干细胞进行体外培养扩增,行表型鉴定后,取第5代细胞,诱导组采用脱细胞神经移植物匀浆进行诱导,非诱导组加入等量无血清培养基,倒置相差显微镜观察诱导后细胞形态变化,免疫细胞化学染色检测诱导后细胞S-100,神经胶质纤维酸性蛋白(glial fibrillary acidic protein GFAP)的表达情况。结果BMSCs表型鉴定为CD44+、CD54+、CD34-,免疫细胞化学染色GFAP、S-100的阳性表达率分别为为(42±4)%和(64±5)%。结果 脱细胞神经移植物可诱导骨髓间充质干细胞分化为施旺细胞样细胞。     

脐带间充质干细胞——组织工程的新视角

目的 从脐带中分离培养脐带间充质干细胞(mesenchymal stem cell, MSC) 并进行鉴定,阐明其多向分化的潜在作用.方法 收集健康胎儿脐带,分离培养脐带中的间充质干细胞,以流式细胞仪对培养的间充质干细胞进行细胞表面标志检测,多种成分联合诱导其向脂肪、成骨方向分化,细胞化学染色检测诱导后的细胞变化.结果 脐带中分离培养的间充质干细胞不表达造血细胞系的标志CD34、CD45、HLA-DR,强表达CD105、CD44、CD90,在适当的诱导条件下可向脂肪及成骨方向分化.结论 脐带中存在具有多向分化潜能的间充质干细胞.     

大鼠脂肪间充质干细胞的分离鉴定与生物学特性研究

脂肪间充质干细胞(adipose-derived mesenchymal stem cells,ADSCs)是一类具有多向分化潜能的成体干细胞,在组织器官修复方面具有潜在应用前景。体外培养条件下脂肪间充质干细胞增殖活性和分化潜能的维持对其应用研究具有重要意义。该研究通过大鼠腹股沟部脂肪组织分离获得了脂肪间充质干细胞,并对其细胞生长曲线、细胞群体倍增时间、细胞克隆形成等进行了检测,从而筛选出细胞生长最适的血清及浓度;再进一步对筛选条件下培养的大鼠脂肪间充质干细胞进行了免疫荧光检测、流式细胞术分析和诱导分化能力鉴定。结果显示,大鼠脂肪间充质干细胞在20%血清浓度下生长状态最好,增殖较快,细胞群体倍增时间较短,细胞克隆形成率可达(27.33±0.58)%。分离的大鼠脂肪间充质干细胞中CD44、CD90、CD106的阳性率分别为99.12%、99.59%、65.81%,CD34分子呈阴性。诱导后,细胞经油红O、碱性磷酸酶、阿新兰染色,结果表明,细胞具有向脂肪、骨、软骨方向分化的潜能。以上结果表明,成功建立了大鼠脂肪间充质干细胞系。     

猫4种不同来源间充质干细胞的生物学特性比较

为比较猫的脂肪、骨髓、羊膜、脐带等器官组织4种不同器官来源间充质干细胞(Mesenchymal stem cells,MSC)的生物学特性,本研究通过全血培养法分离培养骨髓来源的间充质干细胞,并采用消化法分离培养脂肪、脐带和胎盘来源的间充质干细胞,比较它们的细胞形态、生长曲线、成脂成骨分化能力以及细胞表面标志物等生物学特性。结果显示,分离得到的4种不同来源的MSC均呈贴壁生长,细胞形态呈梭形、多棱形;均具有成脂成骨分化能力;脂肪源和骨髓源MSC的细胞增殖速度较快,细胞倍增时间较短,而羊膜与脐带源的MSC增殖能力较差,细胞倍增时间较长,4种细胞中脂肪来源MSC的增长活性最好,细胞传至第9代的时候依然保持良好的增殖活性,提示AD-MSC的临床应用可能比较好;4种MSC细胞表面均高表达CD105、CD90和CD44等标志物,低表达CD34。     

雪貂脂肪间充质干细胞的分离、分化与鉴定

目的分离、多向诱导分化并进行鉴定雪貂脂肪间充质干细胞。方法无菌采取雪貂腹部皮下脂肪,机械剪碎为0.5 mm~2,采用含0.075%的胶原酶I消化,应用高糖-DMEM培养基(添加4 ng/mLβ-FGF)培养,观察细胞形态特征,流式细胞术分析细胞表面抗原标志的表达,并检测其体外成脂、成骨、成软骨分化能力,还进一步尝试了诱导神经分化。结果运用组织块贴壁法可以从新鲜脂肪组织中分离到贴壁生长的类似成纤维细胞样细胞,流式分析结果显示高表达CD29(53.1%),CD90(99.6%),CD105(93.7%),低表达CD11b(36.3%),CD45(28.3%)。这些细胞在体外经诱导可以分化成为脂肪、骨、软骨和神经元。结论从雪貂脂肪组织中可以分离得到脂肪间充质干细胞,这些细胞具有多向分化能力。     

Equine bone marrow mesenchymal or amniotic epithelial stem cells as feeder in a model for the in vitro culture of bovine embryos

Various studies have shown that the in vitro culture environment is one of the key determinants of the blastocyst output. In the present study we investigated the effects of co-culturing bovine embryos with equine bone marrow mesenchymal stem cells (BM-MSCs) or equine amniotic epithelial stem cells (AE-SCs) on in vitro blastocysts development. BM specimens were obtained aseptically from sternal aspirates of horses under local anaesthesia and the isolated cells were resuspended in Dulbecco Modified Earle's Medium supplemented with 10 ng/ml of basic fibroblast growth factor (bFGF). Amniotic membranes were obtained from fresh placentas and, to release the AE cells, amniotic fragments were incubated with 0.05% trypsin for 45 min. Separated AE cells were plated in standard culture medium containing 10 ng/ml epidermal growth factor (EGF). Seven hundred and five cumulus-oocyte complexes were used and, after IVM and IVF, cumulus-free presumptive zygotes were randomly transferred into one of three co-culture systems in which they were cultured up to day 7: (1) co-culture with cumulus cells (control); (2) co-culture with BM-MSCs; and (3) co-culture with AE-SCs. Statistical analyses were performed by ANOVA. Blastocyst developmental rates were significantly different (p < 0.001) between control, AE-SCs and BM-MSCs (respectively 35.45, 41.84 and 30.09%). In conclusion, the AE-SC monolayer create a more suitable microenvironment necessary for inducing local cell activation and proliferation of the growing embryos in comparison with BM-MSCs and cumulus cells. It can be suggested that these cells secrete biologically active substances, including signalling molecules and growth factors of epithelial nature, different to those of the BM cells of mesenchymal origin.     

Chondrogenic differentiation of human bone marrow-derived mesenchymal stromal cells in a three-dimensional environment

Cell therapy combined with biomaterial scaffolds is used to treat cartilage defects. We hypothesized that chondrogenic differentiation bone marrow-derived mesenchymal stem cells (BM-MSCs) in three-dimensional biomaterial scaffolds would initiate cartilaginous matrix deposition and prepare the construct for cartilage regeneration in situ. The chondrogenic capability of human BM-MSCs was first verified in a pellet culture. The BM-MSCs were then either seeded onto a composite scaffold rhCo-PLA combining polylactide and collagen type II (C2) or type III (C3), or commercial collagen type I/III membrane (CG). The BM-MSCs were either cultured in a proliferation medium or chondrogenic culture medium. Adult human chondrocytes (ACs) served as controls. After 3, 14, and 28 days, the constructs were analyzed with quantitative polymerase chain reaction and confocal microscopy and sulfated glycosaminoglycans (GAGs) were measured. The differentiated BM-MSCs entered a hypertrophic state by Day 14 of culture. The ACs showed dedifferentiation with no expression of chondrogenic genes and low amount of GAG. The CG membrane induced the highest expression levels of hypertrophic genes. The two different collagen types in composite scaffolds yielded similar results. Regardless of the biomaterial scaffold, culturing BM-MSCs in chondrogenic differentiation medium resulted in chondrocyte hypertrophy. Thus, caution for cell fate is required when designing cell-biomaterial constructs for cartilage regeneration.     

Characteristics of stem cells derived from the degenerated human intervertebral disc cartilage endplate

Mesenchymal stem cells (MSCs) derived from adult tissues are an important candidate for cell-based therapies and regenerative medicine due to their multipotential differentiation capability. MSCs have been identified in many adult tissues but have not reported in the human intervertebral disc cartilage endplate (CEP). The initial purpose of this study was to determine whether MSCs exist in the degenerated human CEP. Next, the morphology, proliferation capacity, cell cycle, cell surface epitope profile and differentiation capacity of these CEP-derived stem cells (CESCs) were compared with bone-marrow MSCs (BM-MSCs). Lastly, whether CESCs are a suitable candidate for BM-MSCs was evaluated. Isolated cells from degenerated human CEP were seeded in an agarose suspension culture system to screen the proliferative cell clusters. Cell clusters were chosen and expanded in vitro and were compared with BM-MSCs derived from the same patient. The morphology, proliferation rate, cell cycle, immunophenotype and stem cell gene expression of the CESCs were similar to BM-MSCs. In addition, the CESCs could be induced into osteoblasts, adipocytes, chondrocytes, and are superior to BM-MSCs in terms of osteogenesis and chondrogenesis. This study is first to demonstrate the presence of stem cells in the human degenerated CEP. These results may improve our understanding of intervertebral disc (IVD) pathophysiology and the degeneration process, and could provide cell candidates for cell-based regenerative medicine and tissue engineering.     

树鼩骨髓间充质干细胞体外分离培养及成脂成骨诱导

目的：探讨树鼩骨髓间充质干细胞（ BM-MSCs）的体外分离、传代及定向诱导为脂肪细和成骨细胞的可行性。方法通过密度梯度离心联合贴壁培养法对树鼩骨髓间充质干细胞进行体外分离、扩增、纯化,倒置相差显微镜进行形态学观察。用成脂诱导液（ DMEM/F12＋10％FBS＋100 U/mL青霉素＋100μg/mL链霉素＋1.0μmol/L地塞米松＋0.2 mmol/L吲哚美辛＋0.01 mg/mL胰岛素＋0.5 mmol/L IBMX）和成骨诱导液（高糖DMEM＋10％FBS＋100 U/mL青霉素＋100μg/mL链霉素＋50 ng/mL BMP-2）对分离的树鼩BM-MSCs分别定向诱导为脂肪细胞和成骨细胞。结果原代和传代细胞为梭形或三角形,可增殖形成克隆。 BM-MSCs成脂诱导后油红O染色细胞内出现红色脂滴,成骨诱导后茜素红染色可观察到矿化结节。结论密度梯度离心联合贴壁培养法分离培养树鼩BM-MSCs简便可行,获得的BM-MSCs可体外诱导分化为脂肪细胞和成骨细胞。     

Comparison of the Neural Differentiation Potential of Human Mesenchymal Stem Cells from Amniotic Fluid and Adult Bone Marrow

Human mesenchymal stem cells (MSCs) are considered a promising tool for cell-based therapies of nervous system diseases. Bone marrow (BM) has been the traditional source of MSCs (BM-MSCs). However, there are some limitations for their clinical use, such as the decline in cell number and differentiation potential with age. Recently, amniotic fluid (AF)-derived MSCs (AF-MSCs) have been shown to express embryonic and adult stem cell markers, and can differentiate into cells of all three germ layers. In this study, we isolated AF-MSCs from second-trimester AF by limiting dilution and compared their proliferative capacity, multipotency, neural differentiation ability, and secretion of neurotrophins to those of BM-MSCs. AF-MSCs showed a higher proliferative capacity and more rapidly formed and expanded neurospheres compared to those of BM-MSCs. Both immunocytochemical and quantitative real-time PCR analyses demonstrated that AF-MSCs showed higher expression of neural stemness markers than those of BM-MSCs following neural stem cell (NSC) differentiation. Furthermore, the levels of brain-derived growth factor and nerve growth factor secreted by AF-MSCs in the culture medium were higher than those of BM-MSCs. In addition, AF-MSCs maintained a normal karyotype in long-term cultures after NSC differentiation and were not tumorigenic in vivo. Our findings suggest that AF-MSCs are a promising and safe alternative to BM-MSCs for therapy of nervous system diseases.     

Human umbilical cord-derived MSC culture: the replacement of animal sera with human cord blood plasma

Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) hold great potential for their therapeutic use in various clinical diseases. Many publications have reported on human blood-derived alternatives to animal serum for culturing mesenchymal stem cells, such as human serum, allogenic umbilical cord blood serum, and human platelet derivatives. However, it is not clear whether human umbilical cord blood plasma (UCBP), as the surplusage of umbilical cord blood mesenchymal stem cell extraction, could be used. In this study, in order to make the best of umbilical cord blood, the human UCBP was dialyzed to replace fetal bovine serum (FBS) in the culture medium. hUC-MSCs were cultured in the new medium. Cell growth rate, specific biomarkers, and differentiation properties were detected to characterize the cell proliferation and MSC-specific properties. The hUC-MSCs cultured in such derived medium were verified with proliferation rate, cluster differentiation markers, cell cycle, as well as differentiation capabilities. Such dialyzed human UCBP is fully comparable with, if not superior to, FBS in deriving and culturing hUC-MSCs.     

Osteogenic differentiation of encapsulated rat mesenchymal stem cells inside a rotating microgravity bioreactor: in vitro and in vivo evaluation

The objective of this study is to evaluate the in vitro and in vivo osteogenic potential of rat bone marrow mesenchymal stem cells (BM-MSCs) using chitosan/hydroxyapatite (C/HAp) microbeads as encapsulation matrix under osteoinductive medium and dynamic culture conditions. The degradation characteristics of C/HAp microbeads were evaluated under in vitro and in vivo conditions for 180 days. BM-MSCs were encapsulated in C/HAp microbeads with >?85% viability, and were cultured in a slow turning lateral vessel-type rotating bioreactor simulating microgravity conditions for 28 days, under the effect of osteogenic inducers. MTT assay showed that the metabolic activity of encapsulated cells was preserved >?80% after a week. In vitro experiments confirmed that the encapsulated BM-MSCs differentiated into osteoblastic cells, formed bone-like tissue under osteogenic microgravity bioreactor conditions. Preliminary in vivo study indicated C/HAp microbeads containing BM-MSCs were able to repair the surgically-created small bone defects in the rat femur. BM-MSCs-C/HAp composite microbeads may have potential for modular bone regeneration.     

Scaffold-free culture of mesenchymal stem cell spheroids in suspension preserves multilineage potential

While traditional cell culture methods have relied on growing cells as monolayers, three-dimensional (3D) culture systems can provide a convenient in vitro model for the study of complex cell–cell and cell–matrix interactions in the absence of exogenous substrates and may benefit the development of regenerative medicine strategies. In this study, mesenchymal stem cell (MSC) spheroids, or “mesenspheres”, of different sizes, were formed using a forced aggregation technique and maintained in suspension culture for extended periods of time thereafter. Cell proliferation and differentiation potential within mesenspheres and dissociated cells retrieved from spheroids were compared to conventional adherent monolayer cultures. Mesenspheres maintained in growth medium exhibited no evidence of cell necrosis or differentiation, while mesenspheres in differentiation media exhibited differentiation similar to conventional 2D culture methods based on histological markers of osteogenic and adipogenic commitment. Furthermore, when plated onto tissue culture plates, cells that had been cultured within mesenspheres in growth medium recovered morphology typical of cells cultured continuously in adherent monolayers and retained their capacity for multi-lineage differentiation potential. In fact, more robust matrix mineralization and lipid vacuole content were evident in recovered MSCs when compared to monolayers, suggesting enhanced differentiation by cells cultured as 3D spheroids. Thus, this study demonstrates the development of a 3D culture system for mesenchymal stem cells that may circumvent limitations associated with conventional monolayer cultures and enhance the differentiation potential of multipotent cells.     

Serum-free culture of murine primordial germ cells and embryonic germ cells

Fetal calf serum (FCS) has usually been used for culture of embryonic stem (ES) cell as a component of the culture medium. However, FCS contains undefined factors, which promote cell proliferation and occasionally stimulate differentiation of ES cells. Recently, a chemically-defined serum replacement, Knockout Serum Replacement (KSR), was developed to maintain ES cells in an undifferentiated state. In this experiment, we examined the effects of KSR on the growth and differentiation of primordial germ cells (PGCs) and embryonic germ (EG) cells. PGCs were collected 8.5 days postcoitum (dpc) from B6D2F1 (C57BL/6JxDBA/2J) female mice mated with B6D2F1 males. Most of the PGCs that were cultured in FCS-supplemented medium (FCS medium) had alkaline phosphatase (AP) activity and acquired a fibroblast cell shape. In contrast, PGCs in KSR-supplemented medium (KSR medium) proliferated, maintaining round and stem cell-like morphology. In addition, EG cells were established more easily from PGCs cultured in KSR medium than from PGCs cultured in FCS medium. The percentage of undifferentiated colonies of EG cells was significantly higher in KSR medium than in FCS medium. The germ line chimera was also produced from EG cells established in KSR medium. These results suggest that KSR can be used for sustaining an undifferentiated state of PGCs and EG cells in vitro.