人乳牙牙髓干细胞和成人牙髓干细胞研究进展

近年来,成体干细胞不断地从不同的组织中被分离出来,该类细胞具有多向分化潜能、较强的增殖能力和持久的自我更新能力,具备充当组织工程种子细胞的天然优势。2000年和2003年,研究者先后从成人牙髓组织和人乳牙牙髓组织中分离出具有干细胞特征的细胞,这两种细胞的发现对牙组织工程将产生重要的意义。现就这两种成体干细胞的研究进展做一综述,并展望其应用前景。     

乳牙牙髓干细胞的研究进展

乳牙牙髓干细胞是来源于脱落的乳牙牙髓间充质干细胞,具有较强的增殖能力、自我更新能力和多向分化潜能。由于其组织来源易得且无创伤,而成为牙源性干细胞研究领域的新热点。本文将从细胞的分离鉴定、生物学特性、应用前景等几方面对乳牙牙髓干细胞的研究进展做一系统综述。     

人乳牙牙髓干细胞和恒牙牙髓干细胞的蛋白质组学比较

目的 采用蛋白质组学方法研究人乳牙牙髓干细胞（SHED）和恒牙牙髓干细胞（DPSC）中的蛋白表达差异.方法 应用双向凝胶电泳技术分离SHED和DPSC的细胞总蛋白.通过比较两种细胞的蛋白组学图谱,确定差异表达的蛋白点,而后对差异点进行基质辅助激光解析电离飞行时间质谱分析和蛋白数据库信息检索,对差异蛋白进行功能分类.结果 建立了SHED和DPSC的蛋白质组图谱,经软件分析出45个差异蛋白点,其中26个表达上调,19个表达下调,再经质谱鉴定出48种蛋白,其生物学功能涉及细胞周期、代谢等.结论 SHED与DPSC中蛋白的差异表达体现了两种细胞在结构和功能上的异同性,为进一步研究SHED和DPSC在增殖、分化中的差异,以及牙齿相关干细胞在组织工程和再生医学研究中的应用提供参考.     

牙髓干细胞的研究

牙髓干细胞是存在于牙髓组织中的一种成体干细胞，具有高度增殖、自我更新的能力和多向分化的潜能。牙髓干细胞的研究对牙组织工程和牙齿的再生将产生重要的意义。本文就牙髓干细胞的研究现状作一综述，并对其应用前景以及目前存在的问题进行讨论。     

人乳牙牙髓干细胞分化的研究进展

<正>人乳牙牙髓干细胞(stem cells from human exfoliated deciduous teeth,SHED)是口腔来源的干细胞,因高度增殖能力和多分化的潜能,而成为再生医学的热点。本文就其多方向分化潜能进行综述。     

脱落乳牙牙髓干细胞聚合体再生牙髓实验研究

目的    利用动物实验模型证明使用小型猪脱落乳牙牙髓干细胞（stem cells from minipig exfoliated deciduous teeth, SPED）聚合体进行原位牙髓再生的可行性。方法    分离和培养SPED,检测和分析其细胞生物学行为,进而诱导制备SPED聚合体;建立年轻恒牙牙髓坏死的小型猪动物模型,设置SPED聚合体再生组和传统根尖诱导成形治疗组;术后4个月进行常规组织学取材,利用HE、免疫荧光染色等方法观察牙髓再生和牙根尖形成情况。结果    SPED聚合体再生组受试牙齿组织学HE染色检测发现,牙根继续发育并形成正常的根尖形态,此外全长根管内可见类牙髓结构的再生组织,免疫荧光染色可见组织中CGRP、TRPV1、TRPM8表达阳性细胞的规则分布;而传统根尖诱导成形治疗组受试牙齿仅在根管内形成不规则的钙化组织,未见牙髓组织形成。结论    SPED聚合体在小型猪体内可以实现牙髓再生,同时再生牙髓具有正常组织学形态,而且具有牙本质形成和诱导根尖形成的生理功能。     

人乳牙牙髓干细胞在干细胞治疗中的应用

乳牙牙髓干细胞（SHED）是牙源性干细胞的一种,属外胚间充质干细胞。作为一种理想的干细胞来源,SHED在干细胞治疗中有良好的应用前景。本文阐述了SHED的生物学特征及其在干细胞治疗中的优势,探讨了SHED在组织再生和修复中发挥的多向分化潜能、细胞分泌功能和免疫调节功能等方面的功能作用。此外,本文还介绍了SHED在各系统、器官疾病治疗中的临床应用,重点阐述了用SHED进行干细胞移植在牙髓—牙本质再生、颌骨再生、神经系统疾病治疗和免疫系统疾病治疗方面的研究进展。     

牙髓干细胞研究进展

干细胞是一类具有自我更新和分化潜能的细胞，它包括胚胎干细胞和成体干细胞。牙髓干细胞具有成体干细胞所界定的两大特征：较强的自我更新能力和分化潜能。牙髓干细胞因具有临床取材容易并可特异性地分化为牙体矿化结构等特性，目前正受到广泛关注。     

微量元素对牙髓干细胞分化的影响

牙髓干细胞（dental pulp stem cell,DPSC）是牙髓及牙本质再生研究中关键的优选细胞,具有多向分化的能力。微量元素对DPSC分化的影响是近年口腔组织工程的研究热点。微量元素具有广泛的生理生化功能,一方面可直接调控DPSC分化、迁移和增殖能力;另一方面可通过发挥抗菌及免疫调节作用以及改变支架材料的理化...     

丹参促进人脱落乳牙牙髓干细胞神经分化的研究

目的 探讨中药丹参对人脱落乳牙牙髓干细胞(SHED)神经分化功能的影响.方法 利用不同浓度的丹参注射液和神经诱导培养基诱导SHED分化为神经元样细胞.通过观察SHED经诱导后细胞的形态变化和采用Real-Time PCR方法检测神经元标记蛋白Nestin、早期神经元标记蛋白Ⅲ-Tubulin、神经细胞粘附因子NCAM、神经分化因子NeuroD、辅助T淋巴细胞因子TH、NEF等的表达,来鉴定神经元样细胞.结果 丹参注射液诱导后SHED胞体收缩,突起伸出,形似神经元;Real-TimePCR结果显示丹参注射液促进神经元标记蛋白Nestin、早期神经元标记蛋白Ⅲ-Tubulin、神经细胞粘附因子NCAM、神经分化因子NeuroD、NEF的表达.丹参注射液联合神经培养基诱导SHED神经分化的最佳丹参注射液浓度为50mg/ml.结论 中药丹参在一定浓度范围内可促进SHED向神经元样细胞分化.     

改良富血小板血浆促进乳牙牙髓干细胞成骨分化作用研究

目的：体外研究改良富血小板血浆（modified platelet-rich plasma,mPRP）促进人乳牙牙髓干细胞成骨分化的作用。方法：以α-MEM作为基础培养基,分别加入1％、2％、5％、10％4种不同浓度 mPRP 或者10％胎牛血清（对照）,对第4代SHED 连续培养并诱导矿化,碱性磷酸酶试剂盒检测 ALP 活性的变化,qRT-PCR 方法检测细胞内 RUNX2和骨钙素 mRNA 含量的改变。结果：不同浓度的 mPRP 均可以促进乳牙牙髓干细胞的 ALP 活性,且浓度为2％时 A 值最高;qRT-PCR 检测显示2％ mPRP 可以上调乳牙牙髓干细胞内 RUNX2及骨钙素 mRNA 的含量。结论：一定浓度的 mPRP 对乳牙牙髓干细胞的成骨分化具有一定的促进作用。     

Differentiation of stem cells from human deciduous and permanent teeth into spiral ganglion neuron-like cells

ObjectiveStem cells from pulp tissue are a promising cell-based therapy for neurodegenerative patients based on their origin in the neural crest. The aim of this study was to differentiate and evaluate the ability of human dental pulp stem cells from permanent teeth (DPSC) and stem cells from human exfoliated deciduous teeth (SHED) to differentiate into spiral ganglion neurons.DesignAfter isolation and characterization of mesenchymal stem cell properties, DPSC and SHED were treated with the neurotrophins brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and glial cell-derived neurotrophic factor (GDNF). The differentiation was identified by immunostaining and qRT-PCR analysis of neuronal markers and measuring intracellular calcium activity.ResultsAfter 2 weeks of induction, morphological changes were observed in both DPSC and SHED. The differentiated cells expressed neuron-specific class III beta-tubulin, GATA binding protein 3 (GATA3) and tropomyosin receptor kinase B, protein markers of spiral ganglion neurons. These cells also showed upregulation of the genes encoding these proteins, namely GATA3 and neurotrophic receptor tyrosine kinase 2. Intracellular calcium dynamics that reflect neurotransmitter release were observed in differentiated DPSC and SHED.ConclusionThese results demonstrate that dental pulp stem cells from permanent and deciduous teeth can differentiate into spiral ganglion neuron-like cells.     

体外观察三种支架材料对人乳牙牙髓干细胞生物学行为的影响

目的：观察乳牙牙髓干细胞（SHEDs）在3种羟基磷灰石（HA）复合支架材料上黏附、增殖、分化情况。方法：利用正常替换的乳牙分离培养 SHEDs,免疫组织化学法鉴定细胞来源,体外诱导实验观察细胞分化能力。将 SHEDs 分别接种在羟基磷灰石／β-磷酸三钙（HA／TCP）,羟基磷灰石／胶原（HA／COL）和羟基磷灰石／聚乙丙交酯（HA／PLGA）支架材料上复合培养,于4、6、8、10 h 4个时间点检测各细胞黏附率,MTT 比色法检测 SHEDs 增殖情况;碱性磷酸酶（ALP）活性检测、能谱分析钙含量;Von Kossa 染色和灰度扫描细胞矿化能力。结果：SHEDs 在 HA／COL 上的黏附少于 HA／PLGA 和 HA／TCP（P ＜0．05）;HA／PLGA对 SHEDs 矿化诱导能力最强,其次是 HA／TCP,HA／COL 最弱。结论：SHEDs 在 HA／PLGA 上的黏附率、增殖率及矿化能力优于HA／TCP 和 HA／COL。     

Effects of cryopreservation on the characteristics of dental pulp stem cells of intact deciduous teeth

Objectives

The aim of this study was to isolate and cultivate cells from the pulp of 7-day-cryopreserved intact deciduous human teeth and evaluate the effect of cryopreservation on dental pulp stem cell (DPSC) characteristics.

Design

Twenty-six deciduous teeth were collected and allocated in two groups: immediate cell isolation (non-cryopreserved group) and intact cryopreserved (cryopreserved group). The teeth were cryopreserved in dimethylsulfoxide solution and recovered after 7 days. The success rate of isolation, proliferation, surface markers (CD14, CD29, CD34, CD45, CD73, CD90, and HLA-DR), differentiation capacity, and morphology were evaluated.

Results

Isolation success rate was 61% and 30% for the non-cryopreserved and cryopreserved groups, respectively. There were no statistical differences between the groups for the tested surface markers. The cells in both groups were capable of differentiating into three mesenchymal lineages. No statistical differences between the groups were observed through the time course proliferation assay (0, 1, 3, 5, and 7 days); however, the mean time between isolation and the fifth passage was shorter for the non-cryopreserved group (p = 0.035). The morphology of the cells was considered altered in the cryopreserved group.

Conclusion

DPSCs were obtained from cryopreserved intact deciduous teeth without changes in the immunophenotypical characteristics and differentiation ability; however, lower culture rates, proliferation potential, and morphological alterations were observed in relation to the control group.     

Effect of a cryopreservation protocol on the proliferation of stem cells from human exfoliated deciduous teeth

Objective: The aim of the present study was to evaluate the influence of a cryopreservation protocol on the proliferation and viability of stem cells from human exfoliated deciduous teeth (SHEDs).

Materials and methods: Cells from the pulp of three deciduous teeth were isolated and characterized to confirm their stem cell nature. In second passage, part of the cells were submitted to normal conditions of cell culture (Control group), while part of the cells were maintained in 10% DMSO diluted in foetal bovine serum and submitted to the following cryopreservation protocol: 2?h at 4?°C, 18?h at ?20?°C and then at ?80?°C for two intervals (30 days – Cryopreservation I; and 180 days Cryopreservation II). Cell proliferation and cell cycle were evaluated at intervals of 24, 48 and 72?h after plating, and apoptosis-related events were analyzed at 72?h.

Results: All groups exhibited an increase in the number of cells, and no significant differences between the cryopreserved and control groups were observed (p?>?.05). The distribution of cells in the cell cycle phases was consistent with cell proliferation, and the percentage of viable cells was higher than 99% in all groups, indicating that cell viability was not affected by the cryopreservation protocol throughout the experiment.

Conclusion: The proposed cryopreservation protocol is adequate for the storage of SHED, permitting their use in future experimental studies.     

TNF-α对人脱落乳牙牙髓干细胞促破骨细胞形成能力的影响

目的: 探讨肿瘤坏死因子α（tumor necrosis factor -α,TNF-α）对人脱落乳牙牙髓干细胞（stem cells from human exfoliated deciduous teeth,SHED）促破骨细胞形成能力的影响。方法: 通过酶消化法体外分离、培养处于生理性根吸收时期的自然脱落乳牙牙髓干细胞;建立SHED与破骨前体细胞外周血单个核细胞（peripheral blood mononuclear cells, PBMCs）的间接共培养模型,在破骨诱导培养液中加入0、5、10、50、100 ng/mL不同浓度的TNF-α,通过实时定量RT-PCR和Western 免疫印迹检测破骨相关基因及核转录因子κB（nuclear factor-κB,NF-κB）信号通路相关基因的表达。采用SPSS 19.0软件包对数据进行统计学分析。结果: 在10 ng/mL的TNF-α刺激下,PBMCs中破骨相关蛋白CTSK和 TRAP 的表达水平均显著增高。Western免疫印迹和实时定量RT-PCR检测结果显示,SHED胞质内 p-IκBα 和胞核内 p65 蛋白、基因的表达水平在10 ng/mL的TNF-α刺激下显著高于无TNF-α刺激组。结论: 炎症细胞因子TNF-α通过NF-κB信号通路对SHED促破骨细胞形成能力具有调控作用。