三维培养的牙髓干细胞参与牙髓损伤修复能力的实验研究

目的：将体外建立的细胞因子BMP-2作用下牙髓干细胞（DPSC）三维培养体系应用于大鼠牙髓损伤模型中,观察DPSC对牙髓组织损伤修复的能力。方法：已构建的三维培养DPSC的细胞团添加BMP-2体外持续培养7 d,BrdU标记及检测鉴定后,将其置于建立的大鼠牙髓损伤模型洞内,移植4周后HE染色,改良Mallory三色法染色观察,免疫组化检测BrdU标记的细胞分布。结果：移植后4周,DPSC三维细胞培养的牙髓盖髓实验中有骨样牙本质基质形成,没有观察到组织的炎症和坏死。在基质中可以看到骨性成牙本质样细胞,带有长的突起的成牙本质样细胞在骨性牙本质中形成管状牙本质。结论：损伤的牙髓表面植入添加BMP处理的DPSC细胞团能够产生修复性牙本质。     

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...     

牙髓干细胞分化的研究进展

牙髓干细胞(DPSC)是一种具有高度增生、自我更新能力和多相分化潜能的成体干细胞,在一定条件下可向特定的细胞类型分化,在牙髓修复和牙齿再生中发挥着重要的作用。本文主要就DPSC成骨向分化、成牙本质向分化的研究进展作一综述。     

慢病毒介导的Delta1-RNA干扰对人牙髓干细胞增殖及分化的影响

目的 探讨Notch配体Delta1基因的特异性RNA干扰(RNA interference,RNAi)对人牙髓干细胞(dental pulp stem cell,DPSC)增殖及分化的影响.方法 利用Delta1-RNAi慢病毒载体感染体外培养的DPSC获得稳定的Delta1-RNAi DPSC系;实验分3组:经Delta1-RNAi慢病毒感染的DPSC组(慢病毒组),经空慢病毒感染的阴性对照组和正常细胞的正常对照组,采用细胞生长曲线测定( cell counting kit-8,CCK-8)、流式细胞仪及免疫组化等方法检测细胞生长曲线、细胞周期、细胞核增殖抗原表达的变化情况;对各组细胞进行体外成牙本质分化诱导,采用茜素红染色法检测钙化结节数量的差别,并用碱性磷酸酶(ALP)活性检测ALP及蛋白质印迹法检测诱导后各组细胞中牙本质涎磷蛋白( dentin sialophosphoprotein,DSPP)表达量的区别.结果 与正常对照及阴性对照组相比,慢病毒组DPSC增殖能力显著降低,其S期细胞比例及增殖指数分别由正常对照组的22.32±2.35和33.68 ±4.19显著降低至5.44±0.91和16.0 ±6.07(P ＜0.05),细胞核增殖抗原的表达显著下降;慢病毒组细胞经诱导后形成钙化结节数量明显增多,ALP及DSPP表达含量较正常对照组及阴性对照组显著增高.结论 Notch配体Delta1基因被干扰下调后,人DPSC的体外增殖受到抑制,在体外成牙本质诱导培养条件下,细胞向成牙本质细胞的分化加快,证明Notch-Delta1信号转导途径对人DPSC的自我更新及分化的调控起着重要作用,为牙髓损伤后修复提供了理论基础.     

Notch信号通路在牙髓和牙周细胞矿化及组织损伤修复中的调控作用研究

目的 探讨Notch信号通路在人牙髓细胞(dental pulp cells, DPCs)和牙周韧带细胞(periodontal ligament cells, PDLCs)向成牙本质/成骨样细胞分化及组织损伤修复中的调控作用.方法 酶消化法分离培养DPCs和PDLCs,实时荧光定量反转录聚合酶链反应(RT-PCR)检测Notch信号通路相关基因Notch1、Notch2、DLL1和DLL3 mRNA在DPCs和PDLCs矿化诱导过程中表达水平变化;建立大鼠牙髓和牙周联合损伤动物模型,观察4周后牙髓牙本质复合体及牙周附着装置修复情况,免疫组织荧光染色检测Notch1在牙髓和牙周联合损伤修复动物体内模型的表达和分布.结果 DPCs和PDLCs经矿化诱导,Notch1、Notch2、DLL1 mRNA表达均上调,与对照组间的差异有统计学意义(P<0.05);DLL3 mRNA表达上调,与对照组间差异无统计学意义(P>0.05).免疫荧光示Notch1蛋白在损伤处的新生牙髓及牙周韧带组织细胞浆强表达,而在正常牙髓及牙周韧带组织基本无表达.结论 在DPCs和PDLCs诱导成牙本质/成骨分化的过程中,Notch1、Notch2、DLL1呈现相似的表达变化趋势上调,Notch1信号在牙髓及牙周损伤修复的新生组织明显激活,提示Notch信号通路参与DPCs和PDLCs成牙本质/成骨分化,且在牙髓牙本质复合体和牙周附着装置的损伤修复中起重要的调控作用.     

小分子化合物促进牙髓牙本质复合体损伤修复的研究进展

龋病、外伤、医源性刺激等均可引起牙髓牙本质复合体损伤,保存活髓、促进牙髓牙本质复合体的损伤修复对临床治疗至关重要。近年来研究发现,各类小分子化合物可通过细胞内关键信号通路和代谢途径等机制调控炎症,促进牙髓干细胞迁移、增殖、分化,促进血管、神经再生,从而促进牙髓牙本质复合体的损伤修复。该文旨在对近年来小分子化合物在促进牙髓牙本质复合体损伤修复中的应用研究作一综述。     

牙髓干细胞在牙髓组织中分布的研究

目的:通过特异性标志物研究牙髓干细胞(DPSC)在牙髓组织中的分布.方法:利用间充质干细胞特异性标志物STRO-1,外胚间充质干细胞(EMSC)标志物HNK-1,通过激光共聚焦技术,对DPSC在牙髓组织中的分布进行研究.结果:STRO-1抗原阳性细胞在牙髓组织中散在分布,在血管周围较为密集分布,成牙本质细胞层无分布;HNK-1抗原阳性细胞较密集分布在血管周围,成牙本质细胞层也有表达:在血管周围有二者共表达的细胞.结论:DPSC可位于血管周围,且在牙髓组织中有散在分布,与牙髓组织中残留的未分化间充质细胞分布相似,这些血管周围细胞标志物的表达揭示血管周壁可能是DPSC的微环境.     

人牙髓细胞诱导牙本质再生的实验观察

目的:观察人成体牙髓细胞体内诱导牙髓组织修复反应的能力.方法:在矿化诱导液作用下,将一定数量级的人牙髓细胞与β-TCP生物陶瓷颗粒进行复合,植入免疫缺陷鼠磨牙穿髓孔处,7 d、14 d后分别取材进行组织学观察.对照组采用氢氧化钙(Oycal)和空白对照组.结果:组织学观察表明,盖髓术后7 d,各组均出现了牙髓细胞向穿髓孔处迁移、聚集.术后14 d,牙髓细胞组炎症反应仅局限于穿髓孔处,有明显的修复性牙本质桥形成;Dycal组炎症反应涉及到少量冠髓,有部分矿化的纤维性屏障形成;空白对照组炎症反应涉及了大部分冠髓,仅有弥散的骨样牙本质形成.结论:在矿化诱导液作用下,牙髓细胞具有向成牙本质细胞样细胞定向分化的能力,将牙髓细胞植入鼠磨牙的穿髓孔处,显示其具有良好的维持牙髓活力和诱导修复性牙本质形成的能力.     

人牙髓干细胞向成牙本质细胞分化中circRNAs差异表达的研究

目的:检测人牙髓干细胞(DPSCs)向成牙本质细胞分化过程中环状RNA(circRNA)的表达差异。方法:临床分离获取健康的牙髓组织,CD酶消化得到牙髓原代细胞,用鼠抗人STRO-1单克隆抗体孵育人牙髓细胞,用免疫磁珠分选出人DPSCs。用茜素红和碱性磷酸酶试剂鉴定DPSCs分化能力;采用Arraystar基因芯片检测circRNAs在DPSCs成牙本质细胞诱导分化过程中的差异,并做生物信息学分析。结果:在成牙本质诱导的DPSCs组中,有42个circRNAs上调,101个circRNAs下调。GO注释显示差异表达的基因主要参与核转运,胆固醇代谢等生物学过程。Pathway注释显示其主要调节泛素介导的蛋白质水解、癌症途径以及甾体生物合成等途径,调控Wnt、PI3K-Akt和MAPK等多种信号通路。结论:差异表达的circRNAs可能影响DPSCs向成牙本质分化。     

牙髓干细胞、外胚间充质干细胞裸鼠体内分化的实验研究

目的：将免疫磁珠STRO＋-1的牙髓干细胞（DPSC）和外胚间充质干细胞（EMSC）与支架材料复合,观察在裸鼠体内移植后的分化能力,为干细胞分化能力研究提供依据.方法：收集免疫磁珠STRO＋-1的DPSC和EMSC,将其与陶瓷化骨复合移植入裸鼠背部皮下,8周后移植物组织学切片,HE染色观察及免疫组织化学检测DSP分布.结果：DPSC组移植物中可见新生基质,其相邻的结缔组织细胞部分出现极化,似成牙本质样细胞,局部放大可见类似于不典型的牙本质牙髓复合体.EMSC组有基质形成,结构不典型,有骨样基质形成,也存在有类牙本质牙髓复合体样结构.在移植后8周,DPSC组DSP在沉积的新生基质和部分出现极化的细胞胞浆中呈阳性表达.结论：通过免疫磁珠筛选的STRO＋-1的DPSC具有自我更新的特性,能够在体内继续分化形成牙本质样基质.EMSC组移植到裸鼠皮下,也能够形成基质.但是结构不典型.     

MEPE is downregulated as dental pulp stem cells differentiate

Previous studies on dental pulp cell culture have described heterogenous mixtures of cells that differentiate into odontoblasts and form mineralized dentin. OBJECTIVE: The aim of this study was to characterize the matrix extracellular phosphoglycoprotein (MEPE) expression by dental pulp stem cells (DPSC), related to cell differentiation. DESIGN: DPSC differentiation to form mineralized nodules was characterized by Alizarin red staining and micro-Raman spectroscopy. Osteogenesis SuperArray analysis was used to broadly screen for osteogenesis-related genes altered by DPSC differentiation. Relative levels of expression of MEPE and DSP were determined by semiquantitative RT-PCR and Western blot. RESULTS: Mineral analysis showed that as DPSC differentiated, they formed a carbonated hydroxyapatite mineral. Differentiation was initially marked by upregulation by Runx2, TGFbeta-related genes, EGFR and genes involved in collagen metabolism. ALP activity first increased, as DPSCs reached confluence but later decreased when cells further differentiated three weeks after confluence. MEPE was the only marker that was downregulated as DPSCs differentiated. CONCLUSION: DPSC differentiation can be characterized by downregulation of MEPE as other markers of DPSC differentiation, such as DSP, are upregulated. Expression of MEPE related to DSP and can be used to monitor DPSC as they are used for studies of odontoblast differentiation, tissue engineering or vital pulp therapy. The downregulation of MEPE as DPSC differentiate, suggests that MEPE is an inhibitor of mineralization.     

Expression of mineralization markers in dental pulp cells

There is an increasing interest in the utility of dental pulp stem cells (DPSCs) for dentin regeneration. The mechanisms involved in DPSC differentiation remain poorly understood. The purpose of the study was to investigate the mineralization capacity of human dental pulp cells (DPCs) and identify potential markers for odontoblast differentiation. The isolated DPCs expressed mesenchymal stem-cell markers as shown by flow cytometry and could differentiate in vitro into odontogenic, adipogenic, and chondrogenic lineages. Alkaline phosphatase activity of DPCs elevated over time, with significant upregulation on day 21 in odontogenic induction. Quantitative RT-PCR revealed that osteocalcin, dentin sialophosphoprotein (DSPP), and matrix extracellular phosphoglycoprotein (MEPE) expression also increased time dependently in the induction cultures. In conclusion, we isolated DPCs with stem cell characteristics. MEPE and DSPP showed a similar regulatory pattern of DPCs mineralization. MEPE along with DSPP may be potential odontogenetic differentiation markers.     

Effects of Calcitonin Gene-related Peptide on Dental Pulp Stem Cell Viability,Proliferation, and Differentiation

IntroductionPulpitis is an inflammation of dental pulp caused by bacterial proliferation near or within pulpal tissues. In advanced stages, when the inflammation is associated with pulp necrosis, pulp preservation is dependent on dental pulp stem cells (DPSCs) that can differentiate into odontoblastlike cells and produce reparative dentin. In this study, we evaluated the influence of sensory neurons through calcitonin gene-related peptide (CGRP) on DPSC viability and proliferation and the ability of DPSCs to differentiate into mineralizing cells.MethodsCommercially available DPSCs were treated with varying doses of CGRP, and metabolic activity, viability, proliferation, and cell death were evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assays, trypan blue staining, 5-bromo-2'-deoxyuridine cell proliferation assay, and caspase-3 staining, respectively. DPSC differentiation was assessed with alizarin red staining and by quantifying messenger RNA expression of odontoblast makers.ResultsCGRP induced a dose-dependent decrease of DPSC metabolic activity that was prevented by the CGRP receptor antagonist CGRP 8-37. The decrease in the proportion of live cells induced by CGRP is associated with a decrease of cell proliferation but not with caspase-3–dependent apoptosis. Interestingly, dexamethasone-induced DPSC differentiation into mineralizing cells was neither inhibited nor enhanced by CGRP treatment.ConclusionsThe neuropeptide CGRP has an inhibitory effect on DPSC proliferation but does not enhance or inhibit the differentiation of DPSCs into mineralizing cells. This suggests that CGRP might negatively influence the ability of DPSCs to contribute to regenerative or tissue repair processes.     

成牙本质细胞特异分子标志物的研究进展

牙髓干细胞是一类存在于牙髓组织中,保持着高度的增殖和分化潜能,受到刺激后能向终末细胞分化的细胞。在牙髓干细胞的研究过程中,常需要根据成牙本质细胞分子标记物的表达来判断牙髓干细胞的分化进程。随着研究的进展,可供选择的成牙本质细胞分子标记物也越来越广泛。下面就成牙本质细胞分化的特异分子标记物的研究进展作一综述。     

Orthodontic treatment mediates dental pulp microenvironment via IL17A

ObjectiveOrthodontic treatment induces dental tissue remodeling; however, dental pulp stem cell (DPSC)-mediated pulp micro-environmental alteration is still largely uncharacterized. In the present study, we identified elevated interleukin-17A (IL17A) in the dental pulp, which induced the osteogenesis of DPSCs after orthodontic force loading.DesignTooth movement animal models were established in Sprague-Dawley rats, and samples were harvested at 1, 4, 7, 14, and 21 days after orthodontic treatment loading. DPSC self-renewal and differentiation at different time points were examined, as well as the alteration of the microenvironment of dental pulp tissue by histological analysis and the systemic serum IL17A expression level by an ELISA assay. In vitro recombinant IL17A treatment was used to confirm the effect of IL17A on the enhancement of DPSC self-renewal and differentiation.ResultsOrthodontic treatment altered the dental pulp microenvironment by activation of the pro-inflammatory cytokine IL17A in vivo. Orthodontic loading significantly promoted the self-renewal and differentiation of DPSCs. Inflammation and elevated IL17A secretion occurred in the dental pulp during orthodontic tooth movement. Moreover, in vitro recombinant IL17A treatment mimicked the enhancement of the self-renewal and differentiation of DPSCs.ConclusionsOrthodontic treatment enhanced the differentiation and self-renewal of DPSCs, mediated by orthodontic-induced inflammation and subsequent elevation of IL17A level in the dental pulp microenvironment.     

Dentinogenic potential of the dental pulp: facts and hypotheses

The aim of the present article is to discuss observations and hypotheses from different experimental approaches on the biological mechanisms underlying initiation of tertiary dentin formation and therapeutic control of pulp–dentinal regeneration. The specific dentinogenic potential of dental pulp cells in up‐regulating the biosynthetic activity of primary odontoblasts (reactionary dentinogenesis) and differentiation into odontoblast‐like cells (reparative dentinogenesis) is described. The role of biologically active matrices and molecules as signaling factors in the expression of the dentinogenic potential of dental pulp cells, in numerous ex vivo and in vivo models, is reviewed. Data are focused on the mechanisms by which the signaling molecules, in the presence of the appropriate pulp microenvironment and specific mechanical support, can induce competent pulpal cells in the acquisition of odontoblast‐like cell phenotype and reparative dentin formation. The ability of tissue engineering to stimulate reconstruction of the amputated pulp–dentin complex offers exciting opportunities for the future. Advances in molecular biology and bioengineering research might thus be integrated into the clinical problems of endodontology.
Received 13 February 2009; accepted 2 September 2009.     

小分子鹰嘴豆芽素A对人牙髓干细胞成骨分化的影响

目的:探讨不同浓度鹰嘴豆芽素A (biochanin A,BCA)对人牙髓干细胞(human dental pulp stem cells,hDPSCs)成骨分化的影响及相关分子机制.方法:通过组织块法分离培养原代人牙髓干细胞,流式细胞术鉴定其细胞表型.通过CCK-8法检测不同浓度BCA对hDPSCs增殖活性的影响,通...