地塞米松对A系小鼠胚腭突间充质细胞表皮生长因子基因表达的影响

目的:研究地塞米松(DEX)对A系小鼠胚腭突间充质细胞表皮生长因子(EGF)基因mRNA表达的影响。方法：将DEX(10ng/ml)加入培养的A系小鼠胚腭突间充质细胞，并在培养第1、3、5天时收集细胞，提取RNA，应用RT-PCR技术半定量检测腭突问充质细胞EGF基因mRNA的表达水平。结果：DEX可显著促进腭突间充质细胞EGF mRNA的表达，并在加入DEX培养第3天时，这种促进EGF mRNA表达的作用最强。结论：DEX显著促进腭突间充质细胞EGF基因的表达，可能干扰腭突间充质细胞EGF基因的表达而影响了腭发育。     

Dlx1基因在大鼠外胚间充质细胞中表达的研究

目的 探讨Dlxl基因在牙胚发育过程中的调控作用。方法 采用外胚间充质细胞组织块培养法；地高辛标记cDNA原位杂交检测方法和斑点杂交方法，观察Dlxl基因在大鼠外胚间充质细胞，人牙乳头细胞，人牙髓细胞中的表达情况。结果 Dlxl基因在外胚间充质细胞和人牙乳头细胞中mRNA呈强阳性表达，而在牙髓细胞中弱表达。结论 Dlxl基因是牙胚发育过程中重要的调节因子，这种调控作用具有一定的时间性与空间性，它可能主要参与调控早期未分化细胞，而对终末分化细胞作用不显著。     

颌突外胚间充质细胞向成牙本质细胞的定向诱导分化

外胚间充质细胞具有多向分化潜能。它可以进一步分化为成牙本质细胞等多种细胞,并将形成上下颌骨、颞下颌关节盘软骨、牙本质、牙髓、牙骨质、牙周韧带、听神经等组织器官。该细胞在牙齿发育和牙体牙髓损伤修复过程中起重要作用。本文从外胚间充质细胞的起源和特性、颌突外胚间充质细胞的分离和体外培养、外胚间充质细胞的定向诱导分化、外胚间充质细胞向成牙本质细胞的定向误导分化、诱导分化的成牙本质细胞的鉴定等方面进行了综述。     

颌突外胚间充质细胞向成牙本质细胞的定向诱导分化

外胚间充质细胞具有多向分化潜能．它可以进一步分化为成牙本质细胞等多种细胞。并将形成上下颌骨、最下颌关节盘软骨、牙本质、牙髓、牙骨质、牙周韧带、听神经等组织器官。该细胞在牙齿发育和牙体牙髓损伤修复过程中起重要作甩。本文从外胚间充质细胞的起源和特性、颌突外胚间充质细胞的分离和体外培养、外胚间充质细胞的定向诱导分化、外胚间充质细胞向成牙本质细胞的定向诱导分化、诱导分化的成牙本质细胞的鉴定等方面进行了综述。     

腭裂相关基因mcpr1在小鼠腭突发育及腭裂发生中的表达研究

目的检测mcpr1基因的蛋白在正常腭突及小鼠腭裂模型腭突发育中的时空表达模式。方法实验组管饲含全反式维甲酸的植物油诱导建立小鼠腭裂模型,对照组小鼠管饲植物油。2组取胎龄12、13、14、16 d的胎鼠各3只,包埋切片,HE染色观察2组胎鼠腭部发育的形态学变化,免疫组织化学方法观察MCPR1蛋白在2组胎鼠腭突中的表达差异。结果成功建立小鼠腭裂模型。切片HE染色观察发现实验组双侧腭突体积较对照组小,两侧腭突未接触;而对照组腭突融合,腭骨形成。免疫组织化学检查结果表明对照组小鼠胎龄12 d时MCPR1蛋白在腭突上皮细胞呈强阳性表达;而实验组小鼠胎龄12 d时腭突间充质细胞内MCPR1蛋白的表达较强,实验组胎龄16 d小鼠仅在上皮细胞附近的间充质细胞中有阳性表达。同一时间点比较,MCPR1蛋白的表达在实验组均强于对照组（P〈0.05）。结论 MCPR1蛋白的表达变化随腭部发育存在时空表达差异。     

酶消化法培养Balb/c胎鼠下颌突未分化外胚间充质细胞

目的：用酶消化法培养Balb/c胎鼠下颌突外胚间充质细胞，并与组织块法相比较，研究其形态和生长特性。方法：采用1.25g/L的胰酶消化法获取E12.5d Balb/c胎鼠下颌突外胚间充质细胞，用含10^6U/L LIF的D／F12培养细胞，倒置显微镜下观察细胞形态和生长情况，免疫组化鉴定细胞来源及分化状况。结果：培养的细胞呈单层生长，长梭形，有2－4个突起，抗HNK－1、Vimentin、S－100、NSE染色阳性，抗GFAP、NF、MA染色阴性，证实为未分化外胚间充质细胞。结论：用酶消化法可在短期内获得大量的未分化外胚间充质细胞。     

牙胚细胞条件培养液诱导大鼠胚胎面突外胚间充质细胞向成牙本质样细胞分化

目的：探讨牙胚细胞条件培养液（TGC—CM）在诱导面突外胚间充质细胞向成牙本质样细胞分化中的作用。方法：取妊娠12．5d SD大鼠胎鼠第4代下颌突外胚间充质细胞,在牙胚细胞条件培养液（TGC—CM）的诱导下,通过形态学观察、免疫组化、RT—PCR等方法,探索牙胚细胞条件培养液诱导面突外胚间充质细胞向成牙本质样细胞分化的可能。结果：面突外胚间充质细胞在诱导培养基中生长良好。培养7d,在诱导组中细胞出现核极化,有很长的突起,细胞平行排列。抗牙本质涎蛋白（DSP）呈阳性反应。RT—PCR显示mRNA水平表达成牙本质细胞特异的牙本质涎磷蛋白（DSPP）和牙本质基质蛋白-1（DMP-1）。结论：面突外胚间充质细胞在含有多种细胞因子的TGC—CM的作用下能分化为成牙本质样细胞,能为研究牙齿的分化和发育提供良好的模型和实验依据。     

Forskolin体外诱导Balb/c小鼠下颌外胚间充质细胞向神经胶质细胞分化

目的：探讨forskolin诱导小鼠下颌外胚间充质细胞向神经胶质细胞的分化过程。方法：取妊娠12.5d胎鼠第3代下颌外胚间充质细胞，分别在含5、25、50μmol/L forskolinr DMEM/F12培养基中培养。相差镜下观察细胞的形态变化，免疫组化鉴定细胞性质。结果：培养2d，细胞形态及排列发生明显变化，呈两突的长梭形；胸体中有空泡样改变，随时间的增加而明显。变化以25μmol/L组较明显，免疫组化鉴定：抗神经胶质纤维酸性蛋白（GFAP）及S－100染色阳性；NSE及NF染色阴性。结论：forskolin可诱导外胚间充质细胞向神经胶质细胞分化。     

小鼠上颌突和下颌突间充质细胞成骨分化的体外研究

目的：研究上、下颌突间充质细胞在体外的成骨能力。方法 ：体外培养胚胎13.5d（E13.5）的小鼠上、下颌突间充质细胞,观察其细胞形态。取第1代细胞进行成骨诱导培养7 d,通过免疫荧光、ALP染色、茜素红染色和qPCR检测其成骨能力。应用SPSS 18.0软件包对实验结果进行独立样本t检验。结果：E13.5的小鼠上、下颌突间充质细胞能在体外成功培养和传代。成骨诱导可促进上、下颌突间充质细胞表达成骨标志物,但下颌突间充质细胞成骨标志物OCN和OPN的表达、ALP染色和茜素红染色较上颌突间充质细胞弱。结论：上、下颌突间充质细胞在体外能成骨分化,下颌突间充质细胞较上颌突间充质细胞的成骨能力稍弱。     

TGF-β、rhBMP-2体外诱导下颌突外胚间充质细胞向平滑肌细胞分化

目的：探讨TGFβ、rhBMP-2体外诱导下颌突外胚间充质细胞向平滑肌细胞分化的能力。方法：取妊娠12．5d胎鼠第三代下颌突外胚间充质细胞，分别在含60、100mmol/L的TGF－β和1．6、3.2mmol/L的rhBMP-2的DMEM／F12中培养，相差显微镜下观察细胞的形态变化，免疫组化鉴定细胞性质。结果：培养2d,60pmol/L的TGF－β组细胞形态发生明显变化，细胞变得大而扁平，培养4d，免疫组化鉴定约70％的细胞分化为平滑肌细胞，rhBMP-2组细胞形态未见明显改变，1.6nmol/L组免疫组化鉴定约5％的细胞分化为平滑肌细胞，未能诱导分化出神经元细胞。未加LIF的对照组细胞出现向平滑肌细胞的自然分化。结论：TGFβ、rhBMP-2可诱导外胚间充质细胞向平滑肌细胞分化。     

Stand der humanen dentalen Stammzellforschung

This review article arranges the current results of stem cell biology for their use in dentistry. There are different types of stem cells, which are applicable for dental treatments. The use of embryonic stem cells, whose possibilities for breeding an artificial tooth were hardly evaluated, is however ethically precarious. On the other side the ethically harmless adult stem cells, which were isolated for example from bone marrow, were little examined for their capability of differentiation into dental tissues. Therefore their forthcoming use in dentistry is rather improbable. However, dental ectomesenchymal stem cells are more promising for dentistry in future. For example dental pulp stem cells (DPSCs) are capable to differentiate into dentin under in vitro conditions. Moreover it is possible to use periodontal ligament (PDL) stem cells and dental follicle precursors for periodontal tissue differentiations in vitro. Recently new populations of stem cells were isolated from the dental pulp and the PDL. These cells distinguish from the initially isolated DPSCs and PDL stem cells in growth and cell differentiation. Therefore stem cell markers are very important for the characterization of dental stem cells. A significant marker for dental stem cells is STRO-1, which is also a marker for bone marrow derived mesenchymal stem cells. Nonetheless dental stem cells are CD45 negative and they express rarely hematopoietic stem cell markers. These research results plead for the participation of dental stem cells in dental practice in future.     

Notch1蛋白在小鼠下颌切牙发育中的表达

目的探讨Notch1在小鼠下颌切牙牙胚发育过程中的组织学分布。方法制作ICR小鼠下颌切牙不同发育阶段的冰冻组织切片,对小鼠下颌切牙牙胚自牙胚发育起始期至钟状晚期不同发育阶段组织Notch1的分布情况进行免疫组织化学染色。结果 Notch1在小鼠下颌切牙发育蕾状期牙胚的口腔侧上皮中表达,而在和间充质相邻的牙胚上皮中没有表达。从帽状期至钟状期,Notch1在牙胚的中间层表达,而在内釉上皮中没有表达。钟状期的唇侧颈环部位星网状层和部分牙上皮细胞也表达Notch1。此外,Notch1还在牙胚发育不同时期的间充质、牙乳头和早期牙髓中表达。结论 Notch1可能在小鼠下颌切牙发育过程中的牙上皮,特别是内釉上皮的细胞分化,以及牙囊和牙乳头细胞分化及分化完成后的牙髓干细胞的稳定性方面有重要作用。     

Stem cell‐based tooth and periodontal regeneration

Currently regeneration of tooth and periodontal damage still remains great challenge. Stem cell‐based tissue engineering raised novel therapeutic strategies for tooth and periodontal repair. Stem cells for tooth and periodontal regeneration include dental pulp stem cells (DPSCs), periodontal ligament stem cells (PDLSCs), stem cells from the dental apical papilla (SCAPs), and stem cells from human exfoliated deciduous teeth (SHEDs), dental follicle stem cells (DFSCs), dental epithelial stem cells (DESCs), bone marrow mesenchymal stem cells (BMMSCs), adipose‐derived stem cells (ADSCs), embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). To date, substantial advances have been made in stem cell‐based tooth and periodontal regeneration, including dentin–pulp, whole tooth, bioroot and periodontal regeneration. Translational investigations have been performed such as dental stem cell banking and clinical trials. In this review, we present strategies for stem cell‐based tissue engineering for tooth and periodontal repair, and the translational studies.     

Immunohistochemical localization of syndecan-1 in the dental follicle of postnatal mouse teeth

BACKGROUND: Syndecans are cell surface heparan sulfate proteoglycans that modulate the action of growth factors and extracellular matrix components. Syndecan-1 plays important roles during early tooth development, and it is expressed in the dental follicle of fetal tooth germ. However, no studies have followed its expression in the dental follicle during the postnatal period. We hypothesized that syndecan-1 protein expression in the dental follicle may be important for postnatal tooth development, and, thus, examined its expression patterns. METHODS: Syndecan-1 protein expression in the dental follicle of the lower first molar was investigated by immunohistochemistry using embryonic day (E) 18.5 to 21-day-old (d 21) mice. Immunoelectron microscopy was applied to the dental follicle and pulp cells to confirm its membrane localization in mesenchymal cells. RESULTS: Strong syndecan-1 immunostaining was maintained in the dental follicle and the adjacent dental pulp surrounded by the Hertwig's epithelial root sheath (HERS) from d 4 to d 14, but reduced staining was noted at d 21 with the near-completion of tooth eruption. Three dimensionally, syndecan-1-positive areas plugged the apical foramina surrounded by HERS. However, immunostaining was detected constantly in the dental follicle and the dental pulp of the lower incisor at d 21. In addition, membrane localization of syndecan-1 protein was confirmed for the first time in mesenchymal cells, including dental follicle and pulp cells, by immunoelectron microscopy. CONCLUSION: The spatial and temporal expression of syndecan-1 in the dental follicle suggests that this proteoglycan is important for the maintenance of proliferation and/or movement of cells in this region during tooth eruption.     

Clinical utility of stem cells for periodontal regeneration

The aim of this review is to discuss the clinical utility of stem cells in periodontal regeneration by reviewing relevant literature that assesses the periodontal-regenerative potential of stem cells. We considered and described the main stem cell populations that have been utilized with regard to periodontal regeneration, including bone marrow-derived mesenchymal stem cells and the main dental-derived mesenchymal stem cell populations: periodontal ligament stem cells, dental pulp stem cells, stem cells from human exfoliated deciduous teeth, stem cells from apical papilla and dental follicle precursor cells. Research into the use of stem cells for tissue regeneration has the potential to significantly influence periodontal treatment strategies in the future.     

MCPR1在小鼠胚胎发育中的表达

目的:初步探讨新基因m cpr1在小鼠胚胎多组织发育中的表达模式。方法:取妊娠(gestationday,GD)12、14、18 d的C57BL/6N孕鼠,拉颈处死,取出胎鼠,利用已制备的MCPR1多克隆抗体,进行免疫组织化学染色,分析MCPR1的表达情况。结果:免疫组化结果显示:MCPR1在小鼠胚胎多组织的发育中呈现不同的表达模式,在小鼠胚胎14 d(E14)时,M eckel软骨内有少数MCPR1阳性表达细胞,软骨周围阳性细胞较多;在E18时,M eckel软骨内MCPR1阳性表达细胞增多,且前部较后部多。在胚眼发育不同的时期也有不同的表达分布。结论:推测m cpr1基因在颅神经嵴细胞成骨过程中,可能以促PCD基因的身份在软骨细胞的移行中发挥作用;胚眼发育过程中m cpr1基因可能在视泡及晶状体等眼部结构的发生发展中起着一定的作用。     

Dental stem cells and their promising role in neural regeneration: an update

Introduction

Stem cell-based therapies are considered to be a promising treatment method for several clinical conditions such as Alzheimer's disease, Parkinson's disease, spinal cord injury, and many others. However, the ideal stem cell type for stem cell-based therapy remains to be elucidated.

Discussion

Stem cells are present in a variety of tissues in the embryonic and adult human body. Both embryonic and adult stem cells have their advantages and disadvantages concerning the isolation method, ethical issues, or differentiation potential. The most described adult stem cell population is the mesenchymal stem cells due to their multi-lineage (trans)differentiation potential, high proliferative capacity, and promising therapeutic values. Recently, five different cell populations with mesenchymal stem cell characteristics were identified in dental tissues: dental pulp stem cells, stem cells from human exfoliated deciduous teeth, periodontal ligament stem cells, dental follicle precursor cells, and stem cells from apical papilla.

Conclusion

Each dental stem cell population possesses specific characteristics and advantages which will be summarized in this review. Furthermore, the neural characteristics of dental pulp stem cells and their potential role in (peripheral) neural regeneration will be discussed.     

小鼠牙囊细胞的体外培养及表型特征

目的　建立小鼠牙囊细胞(DFC)的体外分离培养方法,研究牙囊细胞的表型特征。方法　用1%的胰蛋白酶消化分离9 d龄Balb/c小鼠的下颌第一磨牙牙胚的牙囊组织进行体外培养,倒置显微镜下观察细胞的形态,扫描电镜观察细胞的表面形貌,SP免疫组化法检测细胞碱性磷酸酶(ALP)、骨涎蛋白(BSP)、骨桥蛋白(OPN)的表达。结果　分离培养的细胞有3种类型:立方形或多角形;长梭形;非常细长的细胞形状。扫描电镜下细胞具有多形性,有大量的线状胞浆突和微绒毛;根据细胞表面有无纤维细丝覆盖,可将细胞分为有纤维细丝、无纤维细丝两个亚群。免疫组化染色显示部分牙囊细胞的ALP、BSP、OPN的表达阳性。结论　牙囊细胞具有多种细胞的表型特征, 有分化为成牙骨质细胞、牙周膜细胞和成骨细胞的潜能。     

Dental follicle stem cells and tissue engineering

Adult stem cells are multipotent and can be induced experimentally to differentiate into various cell lineages. Such cells are therefore a key part of achieving the promise of tissue regeneration. The most studied stem cells are those of the hematopoietic and mesenchymal lineages. Recently, mesenchymal stem cells were demonstrated in dental tissues, including dental pulp, periodontal ligament, and dental follicle. The dental follicle is a loose connective tissue that surrounds the developing tooth. Dental follicle stem cells could therefore be a cell source for mesenchymal stem cells. Indeed, dental follicle is present in impacted teeth, which are commonly extracted and disposed of as medical waste in dental practice. Dental follicle stem cells can be isolated and grown under defined tissue culture conditions, and recent characterization of these stem cells has increased their potential for use in tissue engineering applications, including periodontal and bone regeneration. This review describes current knowledge and recent developments in dental follicle stem cells and their application.