Treated dentin matrix paste as a novel pulp capping agent for dentin regeneration

Regenerating dentin and preserving pulp vitality are the two key targets for the treatment of dental pulp exposure. Calcium hydroxide (CH), the widely used capping agent, may induce potential tunnel defect in reparative dentin and cause inflammation or even necrosis in pulp tissues. This study aimed to produce a novel pulp capping agent with better bioactivities. Treated dentin matrix (TDM) paste (TDMP) was fabricated consisting of TDM powder and aqueous TDM extract. The chemical and biological characteristics of TDMP were investigated, and its effect on the odontogenic differentiation of dental pulp stem cells explored at gene and protein level; the therapeutic effect for pulp exposure in miniature swine was further verified. TDMP possessed better biocompatibility with neutral pH value, significantly promoted the proliferation of dental pulp stem cells, and enhanced the gene and protein expressions of alkaline phosphatase, bone sialoprotein, dentin sialoprotein etc., compared with CH. In vivo pulp capping using TDMP presented the formation of continuous reparative dentin bridge thicker and denser than CH group. Moreover, pulp tissues under TDMP capping sites showed relatively slight angiectasis than those induced by CH. TDMP could achieve both dentin regeneration and vital pulp conservation, and might serve as a feasible substitute for CH in dental pulp repair procedure. Copyright © 2017 John Wiley & Sons, Ltd.     

Bioengineered post‐natal recombinant tooth bud models

The long‐term goal of this study is to devise reliable methods to regenerate full‐sized and fully functional biological teeth in humans. In this study, three‐dimensional (3D) tissue engineering methods were used to characterize intact postnatal dental tissue recombinant constructs, and dental cell suspension recombinant constructs, as models for bioengineered tooth development. In contrast to studies using mouse embryonic dental tissues and cells, here the odontogenic potential of intact dental tissues and dental cell suspensions harvested from post natal porcine teeth and human third molar wisdom tooth dental pulp were examined. The recombinant 3D tooth constructs were cultured in osteogenic media in vitro for 1 week before subcutaneous transplantation in athymic nude rat hosts for 1 month or 3 months. Subsequent analyses using X‐ray, histological and immunohistochemical methods showed that the majority of the recombinant tooth structures formed calcified tissues, including osteodentin, dentin cementum, enamel and morphologically typical tooth crowns composed of dentin and enamel. The demonstrated formation of mineralized dental tissues and tooth crown structures from easily obtained post‐natal dental tissues is an important step toward reaching the long‐term goal of establishing robust and reliable models for human tooth regeneration. Copyright © 2014 John Wiley & Sons, Ltd.     

组织工程膀胱支架材料：应用现状及血管化策略

背景：随着组织工程膀胱研究的日益改进,组织工程膀胱组织在植入体内后的血管化问题,引起了构建组织工程膀胱者的极大关注。目的：结合近年来的相关文献,就组织工程膀胱支架材料的选择、设计与应用,支架材料植入体内后的血管化问题作一综述。方法：由第一作者应用计算机检索PubMed数据库2000年1月至2014年9月的相关文章,检索词为“tissue engineering,bladder,biomaterials/scaffolds,vascularization”;同时检索中国期刊数据库2000年1月至2014年9月的相关文章,检索词为“组织工程,膀胱,支架材料,血管化”,选择文章内容与生物支架材料在组织工程膀胱中的应用及组织工程膀胱血管化相关。结果与结论：组织工程膀胱中目前采用的支架材料主要包括天然生物材料和人工合成聚合物两大类。当前膀胱组织工程研究最主要的目标仍然是：制备接种细胞的最佳支架,确定干细胞的最佳来源,探索干细胞最优分化方式和促进植入支架新生血管和神经的再生,其中促进支架材料的血管化和构建复杂的组织是最具有挑战性的。目前来说,使支架上附着的内膜细胞精确的定向增殖、迁移和分化仍然很难控制。尽管血管网对于细胞和组织的营养供应和代谢废物清除是必要的,但促进血管生成或血管发生的策略仍有限。     

Proteomics and N‐glycoproteomics analysis of an extracellular matrix‐based scaffold‐human treated dentin matrix

Extracellular matrix (ECM)‐based biomaterials developed from mammalian tissues have been successfully used in preclinical and clinical tissue engineering applications. We have previously reported about the applicability of dentin‐based scaffold, treated dentin matrix (TDM), for tooth root regeneration. However, TDM protein composition has not been characterized. Here, we used a shotgun proteomic strategy to profile human TDM proteome. N‐glycoproteins were enriched by lectin affinity chromatography and identified by mass spectrometry. The total human TDM proteome was compared with the previously published human dentin proteome, and bioinformatics analysis were performed accordingly. In total, 708 proteins were identified by mass spectrometry in human TDM, of which 208 were N‐glycoproteins with 318 identified glycosylation sites. Collagens, proteoglycans, small integrin‐binding ligand N‐linked glycoproteins (SIBLINGs), and growth factors, such as COL1A1, biglycan, dentin sialoprotein, and transforming growth factor beta 1, were identified. Glycoproteins were enriched in “biological processes” Gene Ontology terms such as cellular process, biological regulation, response to stimulus, metabolic process, immune system process, and biological adhesion. Thus, our comprehensive study of the human TDM proteome revealed that dentin proteins are more heterogeneous than previously documented. Our findings provide clues for designing new biomaterials for tooth root regeneration and understanding dentin formation.     

Biological approaches toward dental pulp regeneration by tissue engineering

Root canal therapy has been the predominant approach in endodontic treatment, wherein the entire pulp is cleaned out and replaced with a gutta-percha filling. However, living pulp is critical for the maintenance of tooth homeostasis and essential for tooth longevity. An ideal form of therapy, therefore, might consist of regenerative approaches in which diseased/necrotic pulp tissues are removed and replaced with regenerated pulp tissues to revitalize the teeth. Dental pulp regeneration presents one of the most challenging issues in regenerative dentistry due to the poor intrinsic ability of pulp tissues for self-healing and regrowth. With the advent of modern tissue engineering and the discovery of dental stem cells, biological therapies have paved the way to utilize stem cells, delivered or internally recruited, to generate dental pulp tissues, where growth factors and a series of dentine extracellular matrix molecules are key mediators that regulate the complex cascade of regeneration events to be faithfully fulfilled.     

Bioactive injectable aggregates with nanofibrous microspheres and human dental pulp stem cells: A translational strategy in dental endodontics

Regeneration of the pulp–dentin complex with stem cells is a potential alternative to conventional root canal treatments. Human dental pulp stem cells (hDPSCs) have been extensively studied because of their ability to proliferate and differentiate into mineralized dental and non‐dental tissues. Here we combined hDPSCs with two types of injectable poly‐l ‐lactic acid (PLLA) microsphere with a nanofibrous or smooth surface to form bioactive injectable aggregates, and examined their ability to promote pulp regeneration in the root canal in an in vivo model. We investigated the biocompatibility, biosafety and odontogenic potential of fibrous (F‐BIM) and smooth bioactive injectable microspheres (S‐BIM) in vitro and in vivo. Our results demonstrated that PLLA microspheres and hDPSCs were able to form bioactive injectable aggregates that promoted dentin regeneration in both in vitro and in vivo models. Our results suggest that F‐BIM and S‐BIM may induce dentinogenesis upon in vivo grafting, and propose that the potential usefulness of the microsphere–hDPSC aggregates described here should be evaluated in clinical settings. Copyright © 2017 John Wiley & Sons, Ltd.     

Fibrin glue mixed with platelet-rich fibrin as a scaffold seeded with dental bud cells for tooth regeneration

Odontogenesis is a complex process with a series of epithelial‐mesenchymal interactions and odontogenic molecular cascades. In tissue engineering of teeth from stem cells, platelet‐rich fibrin (PRF), which is rich in growth factors and cytokines, may improve regeneration. Accordingly, PRF was added into fibrin glue to enrich the microenvironment with growth factors. Unerupted second molar tooth buds were harvested from miniature swine and cultured in vitro for 3 weeks to obtain dental bud cells (DBCs). Whole blood was collected for the preparation of PRF and fibrin glue before surgery. DBCs were suspended in fibrin glue and then enclosed with PRF, and the DBC‐fibrin glue‐PRF composite was autografted back into the original alveolar sockets. Radiographic and histological examinations were used to identify the regenerated tooth structure 36 weeks after implantation. Immunohistochemical staining was used to detect proteins specific to tooth regeneration. One pig developed a complete tooth with crown, root, pulp, enamel, dentin, odontoblast, cementum, blood vessels, and periodontal ligaments in indiscriminate shape. Another animal had an unerupted tooth that expressed cytokeratin 14, dentin matrix protein‐1, vascular endothelial growth factor, and osteopontin. This study demonstrated, using autogenic cell transplantation in a porcine model, that DBCs seeded into fibrin glue‐PRF could regenerate a complete tooth. Copyright © 2011 John Wiley & Sons, Ltd.     

Advances and perspectives in tooth tissue engineering

Bio‐engineered teeth that can grow and remodel in a manner similar to that of natural teeth have the potential to serve as permanent replacements to the currently used prosthetic teeth, such as dental implants. A major challenge in designing functional bio‐engineered teeth is to mimic both the structural and anisotropic mechanical characteristics of the native tooth. Therefore, the field of dental and whole tooth regeneration has advanced towards the molecular and nanoscale design of bio‐active, biomimetic systems, using biomaterials, drug delivery systems and stem cells. The focus of this review is to discuss recent advances in tooth tissue engineering, using biomimetic scaffolds that provide proper architectural cues, exhibit the capacity to support dental stem cell proliferation and differentiation and sequester and release bio‐active agents, such as growth factors and nucleic acids, in a spatiotemporal controlled manner. Although many in vitro and in vivo studies on tooth regeneration appear promising, before tooth tissue engineering becomes a reality for humans, additional research is needed to perfect methods that use adult human dental stem cells, as opposed to embryonic dental stem cells, and to devise the means to generate bio‐engineered teeth of predetermined size and shape. Copyright © 2016 John Wiley & Sons, Ltd.     

Developing a biomimetic tooth bud model

A long‐term goal is to bioengineer, fully functional, living teeth for regenerative medicine and dentistry applications. Biologically based replacement teeth would avoid insufficiencies of the currently used dental implants. Using natural tooth development as a guide, a model was fabricated using post‐natal porcine dental epithelial (pDE), porcine dental mesenchymal (pDM) progenitor cells, and human umbilical vein endothelial cells (HUVEC) encapsulated within gelatin methacrylate (GelMA) hydrogels. Previous publications have shown that post‐natal DE and DM cells seeded onto synthetic scaffolds exhibited mineralized tooth crowns composed of dentin and enamel. However, these tooth structures were small and formed within the pores of the scaffolds. The present study shows that dental cell‐encapsulated GelMA constructs can support mineralized dental tissue formation of predictable size and shape. Individually encapsulated pDE or pDM cell GelMA constructs were analysed to identify formulas that supported pDE and pDM cell attachment, spreading, metabolic activity, and neo‐vasculature formation with co‐seeded endothelial cells (HUVECs). GelMa constructs consisting of pDE–HUVECS in 3% GelMA and pDM‐HUVECs within 5% GelMA supported dental cell differentiation and vascular mineralized dental tissue formation in vivo. These studies are the first to demonstrate the use of GelMA hydrogels to support the formation of post‐natal dental progenitor cell‐derived mineralized and functionally vascularized tissues of specified size and shape. These results introduce a novel three‐dimensional biomimetic tooth bud model for eventual bioengineered tooth replacement teeth in humans. Copyright © 2017 John Wiley & Sons, Ltd.     

人乳牙牙髓基质细胞的分离培养与牙再生能力

背景:在牙组织工程和牙再生的研究中,寻找合适的种子细胞是当前的中心和热点.目的:分离培养儿童乳牙牙髓基质细胞,比较研究矿化诱导前后牙本质涎磷蛋白表达的差异.设计、时间及地点:观察性实验,于2006-12/2007-12在大庆油田总医院中心实验室完成.对象:选择8～10岁儿童8名,男4名,女4名,排除传染病及内分泌疾病史,乳牙排除牙体牙髓牙周疾病.牙髓取材于颌外门诊拔除的滞留乳磨牙.方法:通过组织块贴壁法获得乳牙牙髓基质细胞,并在含体积分数10%胎生血清的DMEM培养基中原代培养14 d,消化传代后用添加有10-8 mol/L地塞米松,50 μmol/L左旋抗坏血酸,10 nmol/L维生素D3,10 mmol/L β-磷酸甘油钠的DMEM/F12培养基诱导培养14 d,用不含添加成分的完全DMEM培养基培养作对照.主要观察指标:显微镜下观察细胞形态变化和生长规律.免疫细胞化学染色比较诱导前后牙本质涎磷蛋白的表达差异.结果:乳牙牙髓基质细胞呈成纤维细胞样贴壁生长,经矿化诱导14 d后多数细胞由梭形转变成多角形和柱型,胞核大而圆,B0%以卜细胞的细胞质牙本质涎磷蛋白表达阳性.而未经诱导的细胞仍为梭形,仅有2%的细胞牙本质涎磷蛋白染色呈阳性.结论:乳牙牙髓基质细胞经矿化诱导培养后具有向成牙本质细胞分化的潜能,可以尝试作为牙再生研究新的种子细胞来源.     

Therapeutic applications of dental pulp stem cells in regenerating dental,periodontal and oral-related structures

Dental pulp stem cells (DPSCs) have emerged as a promising tool with great potential for use in tissue regeneration and engineering. Some of the main advantages of these cells are their multifaceted differentiation capacity, along with their high proliferation rate, a relative simplicity of extraction and culture that enables obtaining patient-specific cell lines for their use in autologous cell therapy. PubMed, Scopus and Google Scholar databases were searched for relevant articles related to the use of DPSCs in regeneration of dentin-pulp complex (DPC), periodontal tissues, salivary gland and craniomaxillofacial bone defects. Few studies were found regarding the use of DPSCs for regeneration of DPC. Scaffold-based combined with DPSCs isolated from healthy pulps was the strategy used for DPC regeneration. Studies involved subcutaneous implantation of scaffolds loaded with DPSCs pretreated with odontogenic media, or performed on human tooth root model as a root slice. Most of the studies were related to periodontal tissue regeneration which mainly utilized DPSCs/secretome. For periodontal tissues, DPSCs or their secretome were isolated from healthy or inflamed pulps and they were used either for preclinical or clinical studies. Regarding salivary gland regeneration, the submandibular gland was the only model used for the preclinical studies and DPSCs or their secretome were isolated only from healthy pulps and they were used in preclinical studies. Likewise, DPSCs have been studied for craniomaxillofacial bone defects in the form of mandibular, calvarial and craniofacial bone defects where DPSCs were isolated only from healthy pulps for preclinical and clinical studies. From the previous results, we can conclude that DPSCs is promising candidate for dental and oral tissue regeneration.     

三氧化矿化物凝聚体用于深龋意外穿髓的疗效观察

目的 评价三氧化矿化物凝聚体(MTA)用于深龋意外穿髓时直接盖髓术的临床疗效.方法 将38例患者(38颗牙)按随机数字表法分为MTA组和氢氧化钙糊剂组,每组19颗.先用2％利多卡因小棉球置于龋洞内表面麻醉,去尽腐质,备洞,生理盐水缓慢冲洗窝洞,隔湿.分别将MTA和氢氧化钙糊剂覆盖于暴露的牙髓上约1.0mm厚,用小棉球吸取多余水分,然后用丁香油氧化锌糊剂暂封,观察15 d无症状后行永久充填.治疗后6个月和1年随访,观察盖髓后患牙症状、牙髓活力、X线片等的变化指标.结果 所有患者术后均获6个月和1年的随访,MTA组19颗患牙16颗成功,成功率为84.2％.牙髓活力正常,X线片可见修复性牙本质形成;3颗失败.氢氧化钙糊剂组19颗患牙7颗成功,成功率为36.8％;12颗失败.2组疗效比较差异有统计学意义(P＜0.05).结论 MTA是用于成人恒牙直接盖髓术有效的盖髓剂.     

Bioactive polymeric scaffolds for osteogenic repair and bone regenerative medicine

The loss of bone tissue is a striking challenge in orthopedic surgery. Tissue engineering using various advanced biofunctional materials is considered a promising approach for the regeneration and substitution of impaired bone tissues. Recently, polymeric supportive scaffolds and biomaterials have been used to rationally promote the generation of new bone tissues. To restore the bone tissue in this context, biofunctional polymeric materials with significant mechanical robustness together with embedded materials can act as a supportive matrix for cellular proliferation, adhesion, and osteogenic differentiation. The osteogenic regeneration to replace defective tissues demands greater calcium deposits, high alkaline phosphatase activity, and profound upregulation of osteocalcin as a late osteogenic marker. Ideally, the bioactive polymeric scaffolds (BPSs) utilized for bone tissue engineering should impose no detrimental impacts and function as a carrier for the controlled delivery and release of the loaded molecules necessary for the bone tissue regeneration. In this review, we provide comprehensive insights into different synthetic and natural polymers used for the regeneration of bone tissue and discuss various technologies applied for the engineering of BPSs and their physicomechanical properties and biological effects.     

猪牙乳头细胞与β-磷酸三钙支架构建牙髓牙本质复合体样结构

目的：牙乳头细胞是牙髓细胞、牙本质细胞的前体细胞，应用组织工程方法探讨以猪牙乳头细胞为种子细胞构建牙髓牙本质复合体的可行性。方法：实验于2004-03／2005-11在上海市口腔医学重点实验室完成。以第1代猪牙乳头细胞为种子细胞与β-磷酸三钙为支架材料复合后接种在裸鼠皮下。移植在裸鼠皮下的β-磷酸三钙支架与牙乳头细胞复合物为实验组，同期移植牙胚作为阳性对照组，同期植入的空白β-磷酸三钙支架材料作阴性对照组。每组3个样本，在同一裸鼠皮下植入。8周后取材进行组织学（苏木精-伊红染色及Goldner＇色法染色）、牙本质涎蛋白免疫组织化学及透射电镜检测。结果：①移植物组织学切片显示在支架材料孔隙内形成了牙髓牙本质复合体样结构，由牙本质基质样物质、前期牙本质样物质及牙髓样组织组成。在牙本质样物质内部可见少量牙本质小管，牙髓样组织外层细胞较为密集且单层排列，表现出成牙本质细胞样细胞的特征。②免疫组织化学染色显示，在邻近成牙本质细胞样细胞周围的前期牙本质内牙本质涎蛋白呈阳性表达。③透射电镜结果显示，实验组局部可见牙本质小管样结构。结论：以猪牙乳头细胞为种子细胞、β-磷酸三钙为支架材料，成功构建出牙髓牙本质复合体样结构。     

TGFβ3 secretion by three‐dimensional cultures of human dental apical papilla mesenchymal stem cells

Mesenchymal stem cells (MSCs) can be isolated from dental tissues, such as pulp and periodontal ligament; the dental apical papilla (DAP) is a less‐studied MSC source. These dental‐derived MSCs are of great interest because of their potential as an accessible source for cell‐based therapies and tissue‐engineering (TE) approaches. Much of the interest regarding MSCs relies on the trophic‐mediated repair and regenerative effects observed when they are implanted. TGFβ3 is a key growth factor involved in tissue regeneration and scarless tissue repair. We hypothesized that human DAP‐derived MSCs (hSCAPs) can produce and secrete TGFβ3 in response to micro‐environmental cues. For this, we encapsulated hSCAPs in different types of matrix and evaluated TGFβ3 secretion. We found that dynamic changes of cell–matrix interactions and mechanical stress that cells sense during the transition from a monolayer culture (two‐dimensional, 2D) towards a three‐dimensional (3D) culture condition, rather than the different chemical composition of the scaffolds, may trigger the TGFβ3 secretion, while monolayer cultures showed almost 10‐fold less secretion of TGFβ3. The study of these interactions is provided as a cornerstone in designing future strategies in TE and cell therapy that are more efficient and effective for repair/regeneration of damaged tissues. Copyright © 2015 John Wiley & Sons, Ltd.     

Induction of reparative dentin formation by ultrasound-mediated gene delivery of growth/differentiation factor 11

Bone morphogenetic proteins (BMPs) are morphogens implicated in embryonic and regenerative odontogenic differentiation. Gene therapy has the potential to induce reparative dentin formation for potential pulp capping. We have optimized the gene transfer of Growth/differentiation factor 11 (Gdf11)/Bmp11 plasmid DNA into dental pulp stem cells by sonoporation in vivo. Dental pulp tissue treated with plasmid pEGFP or CMV-LacZ in 5-10% Optison (Molecular Biosystems Inc., San Diego, CA) and stimulated by ultrasound (1 MHz, 0.5 W/cm(2), 30 sec) showed significant efficiency of gene transfer and high level of protein production selectively in the local region, within 500 microm of the amputated site of the pulp tissue. The Gdf11 cDNA plasmid transferred into dental pulp tissue by sonoporation in vitro, induced the expression of dentin sialoprotein (Dsp), a differentiation marker for odontoblasts. The transfection of Gdf11 by sonoporation stimulated a large amount of reparative dentin formation on the amputated dental pulp in canine teeth in vivo. These results suggest the possible use of BMPs using ultrasound-mediated gene therapy for endodontic dental treatment.     

Glial cell‐derived neurotrophic factor promotes dental pulp stem cell migration

Preserving the vitality of the teeth is critical in maintaining the function and aesthetics of teeth during dental treatment. Dental pulp stem cells (DPSCs) are mesenchymal cells that are demonstrated to possess stem cell properties, such as self‐renewal, proliferation, and pluripotency. DPSCs can be obtained through non‐invasive procedure from the dental pulp and become potential resources for tissue regeneration. Neurotrophic factors are known to promote survival and growth of neurons. In the present study, we examined the expression of the glial cell‐derived neurotrophic factor (GDNF) family ligands and receptors and characterized the intracellular localization of them in DPSCs. GDNF increased the migration of the DPSCs. In addition, we found that the AKT and MAPK pathways were downstream of GDNF in regulating the DPSC wound healing and migration. Our results indicate that neurotrophic factors play a role in dental pulp regeneration and may be potential novel therapies for post pulpotomy treatment in adult teeth.     

Biomaterials in myocardial tissue engineering

Cardiovascular disease is the leading cause of death in the developed world, and as such there is a pressing need for treatment options. Cardiac tissue engineering emerged from the need to develop alternative sources and methods of replacing tissue damaged by cardiovascular diseases, as the ultimate treatment option for many who suffer from end‐stage heart failure is a heart transplant. In this review we focus on biomaterial approaches to augmenting injured or impaired myocardium, with specific emphasis on: the design criteria for these biomaterials; the types of scaffolds – composed of natural or synthetic biomaterials or decellularized extracellular matrix – that have been used to develop cardiac patches and tissue models; methods to vascularize scaffolds and engineered tissue; and finally, injectable biomaterials (hydrogels) designed for endogenous repair, exogenous repair or as bulking agents to maintain ventricular geometry post‐infarct. The challenges facing the field and obstacles that must be overcome to develop truly clinically viable cardiac therapies are also discussed. Copyright © 2014 John Wiley & Sons, Ltd.     

Effect of Low-Intensity Pulsed Ultrasound on the Expression of Calcium Ion Transport-Related Proteins during Tertiary Dentin Formation

Low-intensity pulsed ultrasound (LIPUS) is known for its positive effect on bone healing and reparative regeneration. This study investigated whether LIPUS affects reparative progression of the tooth and the expression of calcium ion transport-related proteins in odontoblasts and dental pulp cells using a rat dentin–pulp complex injury model. Forty male adult Sprague-Dawley rats underwent cavity preparation in the right maxillary first molar: 20 received LIPUS irradiation on the cavity-prepared tooth; 20 received LIPUS irradiation on the left maxillary first molar. Rats were randomly allocated into four groups: blank control group, LIPUS group, cavity-prepared group, cavity-prepared?+?LIPUS group. LIPUS irradiation (frequency: 1.5?MHz, 200-µs pulse width, 1-kHz pulse repetition frequency, 30 mW/cm² spatial averaged temporal averaged intensity) was administered individually for 20?min daily. Rats were sacrificed 1, 3, 7 and 14 d post-operation. The histopathological and cellular morphologic changes in the dentin–pulp complex were detected with hematoxylin and eosin staining. Expression of calcium ion transport-related proteins (Cav1.2, NCX1 and TRPV1) was determined with immunohistochemical staining and imaging analysis. Histopathological analysis revealed obvious reparative dentin formation at day 14 in the cavity-prepared?+?LIPUS group compared with the other groups. Expression levels of Cav1.2, NCX1 and TRPV1 increased significantly by 22%, 53% and 23%, respectively, at day 1 and increased significantly by 23%, 27% and 22%, respectively, at day 3 in the cavity-prepared?+?LIPUS group (p?<0.05) compared with the cavity-prepared group. LIPUS has a positive effect on the expression of calcium transport-related proteins during early-stage dentin injury and facilitates tertiary dentin formation; the mechanism for this likely relates to the inflammatory reaction and a mechanical effect.     

人牙髓干细胞的体外培养及神经样诱导分化

背景：牙髓组织来源干细胞的发现及概念的确立有助于从细胞水平上认识牙齿发育和再生修复机制。目的：了解人牙髓干细胞向神经元样细胞诱导分化能力和诱导分化条件。方法：取健康青年人的第三磨牙的牙髓组织后,制成单细胞悬液,加入含有体积分数为15%胎牛血清α-MEM培养基在6孔板培养,传代培养后加入丁羟基茴香醚、forskolin、β-巯基乙醇、碱性成纤维细胞生长因子诱导剂进行培养。结果与结论：免疫荧光和反转录-聚合酶链反应检测显示,诱导2周后人牙髓细胞除了stro-1,Col-Ⅰ,牙本质涎蛋白表达阳性外,还有巢蛋白,神经元特异性烯醇化酶的表达也是阳性,而牙龈纤维细胞表达均为阴性。说明人牙髓组织中存在成体干细胞,在一定的诱导培养条件下,牙髓干细胞有向神经元样细胞分化的潜能。