小型猪富血小板血浆对牙周膜干细胞的成骨诱导

背景:组织工程技术为牙周炎致骨组织缺损的修复提供了新的思路。目的:探寻富血小板血浆在小型猪牙周膜干细胞成骨诱导中的作用。方法:采集贵州小型猪静脉血,三次离心制备富血小板血浆。采用组织块法分离培养小型猪牙周膜干细胞,分别将含体积分数0.8%,1.0%,1.2%的富血小板血浆与牙周膜干细胞共同培养3,7,14,21d,以未添加富血小板血浆的牙周膜干细胞作为对照。结果与结论:体积分数0.8%,1.0%,1.2%的富血小板血浆成骨诱导第14天,碱性磷酸酶活性达到峰值,其中体积分数1.0%的富血小板血浆诱导的细胞碱性磷酸酶活性最高,第21天时碱性磷酸酶活性降低。茜素红染色显示富血小板血浆成骨诱导第21天细胞染色呈阳性。单克隆纯化后细胞的生长曲线从第3天起进入对数生长期,第8天细胞数量达到顶峰。说明富血小板血浆具有诱导牙周膜干细胞成骨的能力,以体积分数1.0%时诱导成骨效率最优。     

富血小板血浆对体外培养骨骼肌干细胞增殖及成骨活性的作用

背景:已有研究发现富血小板血浆可以影响骨髓间充质干细胞和脂肪干细胞的生长和分化.目的:观察富血小板血浆对体外培养的骨骼肌干细胞增殖与诱导成骨的影响,探讨富血小板血浆影响骨骼肌干细胞的机制.设计、时间及地点:随机对照动物实验,于 2008-06/10在上海交通大学附属第六人民医院中心实验室完成.材料:普通级新西兰大白兔9只,体质量2.5～3 kg.年龄1岁左右,雌雄不限.方法:取兔右后肢比目龟肌体外培养新西兰大白兔骨骼肌干细胞.取兔耳中央动脉血,经离心处理后制备富血小板血浆.将细胞分为实验组与对照组,实验组以含12.5%自体富血小板血浆的条件培养液干预,对照组不进行富血小板血浆干预.主要观察指标:①细胞形态学观察.②以四甲基偶氮唑盐法检测细胞增殖活性.③以碱性磷酸酶钙钴法染色、碱性磷酸酶活性测定、茜索红染色和骨钙素免疫荧光染色检测细胞成骨活件.结果:四甲基偶氮唑盐法显示富血小板血浆诱导实验组较对照组增殖明显(P<0.01);碱性磷酸酶活性较对照组增高明显(P<0.01).富血小板血浆诱导实验组碱性磷酸酶染色阳性,骨钙素免疫荧光染色阳性,茜素红染色可见钙结节形成.结论:富血小板血浆对体外培养的骨骼肌干细胞增殖与成骨分化活性具有显著的促进作用.     

兔骨髓间充质干细胞向成骨细胞诱导分化的不同培养方法

背景：目前传统骨髓间充质干细胞的培养方法是应用异种血清为培养基，但其存在种间疾病传播、潜在免疫排斥反应甚至是伦理学争议等问题；且与卫生部公布的《组织工程化组织移植治疗技术管理规范》的要求相违背。自体富血小板血浆是生物自体的全血提取物，内含多种且含量丰富的生长因子。
　　目的：使用自体富血小板血浆替代传统异种血清，探讨其对兔骨髓间充质干细胞诱导分化为成骨细胞的影响，方法：从兔髂后上棘穿刺抽出8 mL骨髓并加肝素抗凝，密度梯度离心富集骨髓间充质干细胞，分为自体富血小板血浆组、胎牛血清组，分别加入含10%自体富血小板血浆、体积分数10%胎牛血清。在传至4代时将自体富血小板血浆组和胎牛血清组细胞各自分为实验组和对照组，实验组对培养及成分进行改变；对照组培养基不变。通过生长曲线测定各代细胞的增殖情况；通过对各组细胞进行碱性磷酸酶活性测定，判断其成骨分化状况。
　　结果与结论：骨髓间充质干细胞生长曲线可见各代细胞增殖良好。对第4代各组细胞进行碱性磷酸酶活性检测，培养第12天，第4代自体富血小板血浆实验组及胎牛血清实验组的碱性磷酸酶活性均显著高于其相应对照组；自体富血小板血浆组对照组、实验组碱性磷酸酶活性显著高于胎牛血清组的对照组、实验组，差异有显著性意义(P<0.01)。提示使用自体富血小板血浆替代异种血清培养骨髓间充质干细胞是一种安全可靠、操作简单、纯度活性高的诱导骨髓间充质干细胞的成骨分化方法。     

富血小板血浆促进脂肪间充质干细胞的体内外成骨

背景：添加富血小板血浆可促进细胞体外成骨表型的快速转化,从而有效成骨.目的：观察富血小板血浆对脂肪间充质干细胞体内和体外成骨能力的影响.方法：第3代兔脂肪间充质干细胞进行成骨诱导培养,分为对照组和富血小板血浆组.细胞接种到钙磷陶瓷支架上后,体内外观察细胞/载体复合物的成骨情况.结果与结论：两组细胞随着诱导时间的延长碱性磷酸酶活性增高,达到高峰值后随后逐渐下降,诱导后14 d时,富血小板血浆组即达到高峰值,对照组18 d达到高峰值.细胞/载体复合体切片Von Kossa染色显示两组载体的孔隙内衬面呈多层黑染状,有大量钙盐沉积.甲苯胺蓝染色显示载体的孔隙中可见成熟的骨质存在,周边区域较中心多.体外钙盐沉积对照组多,体内成骨面积富血小板血浆组多（P 〈 0.05）.说明,富血小板血浆可有效诱导脂肪间充质干细胞体内和体外成骨.     

地塞米松诱导牙周膜干细胞的定向成骨分化及凋亡

背景：牙周膜干细胞是一类起源于牙组织的成体干细胞,具有良好的成骨分化能力,有望在骨组织工程中得到应用。
　　目的：观察成骨诱导液对牙周膜干细胞成骨分化能力及细胞早期凋亡的影响。
　　方法：从原代牙周膜组织中分离得到牙周膜干细胞,以1×104/cm2浓度铺板后开始诱导。利用1,10,100 nmol/L地塞米松、β-磷酸甘油钠、维生素C为成骨诱导剂,以碱性磷酸酶活性检测、茜素红矿化结节染色、荧光定量PCR等方法对细胞成骨情况进行鉴定,采用AnnexinV/PI双染法检测细胞凋亡情况。
　　结果与结论：地塞米松可有效诱导牙周膜干细胞成骨分化,可显著提高碱性磷酸酶活性,促进茜素红矿化结节形成,提高成骨相关基因骨粘连蛋白及Ⅰ型胶原表达。根据碱性磷酸酶活性和矿化结节实验结果,地塞米松的成骨诱导具有浓度梯度效应,其中100 nmol/L 地塞米松具有最佳成骨诱导能力。细胞凋亡结果提示,地塞米松诱导的成骨分化具有一定促凋亡作用,可诱导牙周膜细胞的早期凋亡。     

维甲酸诱导小型猪牙周膜干细胞的体外成骨

背景:近期研究发现维甲酸对胚胎干细胞及多种成体干细胞具有成骨方向诱导的作用。目的:观察维甲酸对小型猪牙周膜干细胞体外成骨作用的影响。方法:采用组织块法获得小型猪牙周膜细胞,有限稀释法纯化小型猪牙周膜干细胞,免疫荧光法检测STRO-1、免疫细胞化学法检测波形蛋白、角蛋白鉴定小型猪牙周膜干细胞。CCK8法测定小型猪牙周膜干细胞增殖曲线,检测小型猪PDLSC克隆形成率。使用维甲酸对第3代小型猪牙周膜干细胞进行成骨诱导,茜素红染色检测矿化结节,免疫细胞化学方法检测成骨相关基因骨桥蛋白、骨钙素、Ⅰ型胶原、Ⅲ型胶原的表达。结果与结论:有限稀释法分离纯化小型猪牙周膜干细胞STRO-1,波形蛋白阳性表达,角蛋白阴性表达,克隆形成率为2.8%,维甲酸诱导14d后,碱性磷酸酶染色阳性,诱导21d后茜素红染色阳性,免疫细胞化学法检测骨桥蛋白、骨钙素、Ⅰ型胶原阳性表达,Ⅲ型胶原阴性表达。结果表明小型猪牙周膜干细胞能够被维甲酸诱导向成骨样细胞分化。     

富血小板血浆诱导犬骨髓间充质干细胞的体外成骨

背景:富血小板血浆中含有大量骨再生所需的生长因子,且各生长因子的比例是机体自身形成的,具有良好的协同作用.目的:探讨富血小板血浆体外诱导犬骨髓间充质干细胞成骨的效果.设计、时间及地点:细胞学体外观察,于2007-06/2008-02在中南大学湘雅医院中心实验室完成.材料:健康12月龄雄性比格犬,由中南大学湘雅医学院实验动物部提供.方法:收集第3代犬骨髓间充质干细胞,分为4组:对照组加入标准培养基;成骨诱导培养基组向培养板孔内加入含胎牛血清、地塞米松、β-甘油磷酸钠、维生素C的高糖DMEM培养基;富血小板血浆组根据预实验结果,向培养板内加入含体积分数为6.25%富血小板血浆的低糖DMEM培养基;联合组向培养板内加入含地塞米松、β-甘油磷酸钠、维生素C、体积分数为6.25%富血小板血浆的高糖DMEM培养基.主要观察指标:细胞内碱性磷酸酶活性,免疫细胞化学染色检测I型胶原的表达,改进Yon Kossa染色标记钙结节形成情况,RT-PCR检测诱导后骨钙素mRNA的表达.结果:各组碱性磷酸酶活性均随诱导时间的延长而逐渐增高,联合组升高幅度最为明显(P<0.05).诱导7,14 d后,成骨诱导培养基组、联合组I型胶原均呈阳性表达,富血小板血浆组、对照组I型胶原始终呈阴性表达.诱导14 d后,成骨诱导培养基组、联合组可见卵圆形钙结节.诱导7,14 d后,对照组与富血小板血浆组之间骨钙素mRNA表达水平无明显差异(P>0.05),此2组骨钙素mRNA表达水平均明显低于成骨诱导培养基组、联合组(P<0.05);成骨诱导培养基组骨钙素mRNA表达水平明显低于联合组(P<0.05).结论:经成骨条件培养基诱导培养的骨髓基质干细胞,富血小板血浆能在体外显著诱导其成骨指标的表达.     

富血小板血浆促进脂肪间充质干细胞的体内外成骨

背景:添加富血小板血浆可促进细胞体外成骨表型的快速转化,从而有效成骨。目的:观察富血小板血浆对脂肪间充质干细胞体内和体外成骨能力的影响。方法:第3代兔脂肪间充质干细胞进行成骨诱导培养,分为对照组和富血小板血浆组。细胞接种到钙磷陶瓷支架上后,体内外观察细胞/载体复合物的成骨情况。结果与结论:两组细胞随着诱导时间的延长碱性磷酸酶活性增高,达到高峰值后随后逐渐下降,诱导后14d时,富血小板血浆组即达到高峰值,对照组18d达到高峰值。细胞/载体复合体切片VonKossa染色显示两组载体的孔隙内衬面呈多层黑染状,有大量钙盐沉积。甲苯胺蓝染色显示载体的孔隙中可见成熟的骨质存在,周边区域较中心多。体外钙盐沉积对照组多,体内成骨面积富血小板血浆组多(P<0.05)。说明,富血小板血浆可有效诱导脂肪间充质干细胞体内和体外成骨。     

富血小板血浆对人骨髓间充质干细胞成骨诱导的影响

背景:富血小板血浆足经过特殊方法提取的血小板含量丰富的血浆,相较普通血清含有更丰富的细胞因子,如血小板衍生因子、转化生长因子β、血管内皮生长因子等.目的:观察富血小板血浆对成骨诱导人骨髓间充质干细胞生物学特性的影响,拟探讨促进人骨髓间充质干细胞的增殖与诱导成骨细胞的培养方法.设计、时间及地点:配对样本对比观察,于2007-03/2008-03在中山大学组织工程实验室完成.对象:18名健康志愿者,男12名,女6名,平均年龄27.5岁.随机分为3组:富血小板血浆组、胎生血清组、无血清对照组,每组6人.方法:抽取18名健康志愿者自体外周静脉血获取富血小板血浆.采用密度梯度离心法获取健康志愿者骨髓间充质干细胞,常规原代培养,传代诱导培养时根据分组情况,分别采用10%AB型血清、10%自体富血小板血浆与无血清,配比高糖DMEM培养基、50mg/L抗坏血酸、1008mol/L地塞米松、103mol/L-β甘油磷酸钠.主要观察指标:倒置相差显微镜、扫描电镜观察各组细胞彤态,MTT法检测细胞增殖情况,细胞碱性磷酸酶活性、骨钙素水平.结果:3组细胞均存接种后12～24 h开始贴壁,并由圆形逐步变化为梭型、多角形、有多个突起的不规则形状等.细胞传代诱导培养后,富血小板血浆组与胎生血清组细胞生长迅速,明显快于无血清对照组(P<0.05).从传代培养第2、4、6代的细胞生长看,随着培养时间的延长富血小板血浆组细胞增殖明显快于胎生血清组.3组细胞碱性磷酸酶活性与骨钙素随诱导时间的延长而增高,培养第3,6,9,12天胎生血清组碱性磷酸酶活性较富血小板血浆组低,培养第15天两组无明显差异.培养第3,6,9天富血小板血浆组细胞内骨钙素含量与胎生血清组无明显差别,12 d后明显高于胎生血清组.无血清对照组碱性磷酸酶活性及骨钙索含量较富血小板血浆组变化程度明显减小.并且各时间点碱性磷酸酶活性与骨钙素含量均低于富血小板血浆组(P<0.01).结论:自体富血小板血浆能够有效加快人骨髓间充质干细胞的增殖,并能有效促进诱导培养的人骨髓间充质干细胞成骨特性表达.     

维甲酸对小型猪牙周膜干细胞成骨诱导能力的比较研究

目的 分离、培养、鉴定小型猪牙周膜干细胞（PDLSCs）并使用不同浓度的维甲酸（RA）对其进行成骨方向诱导,观察各浓度RA诱导后小型猪PDLSCs的碱性磷酸酶活性、相关成骨基因表达的差异。方法 采用组织块法获得小型猪PDLCs,有限稀释法纯化小型猪PDLSCs,免疫荧光法检测STRO-1、免疫细胞化学法检测波形蛋白、角蛋白鉴定小型猪PDLSCs。分别使用0.5μm、1μm、2μm RA对小型猪PDLSCs进行成骨诱导,14 d后行ALP染色,诱导21 d后,茜素红染色检测矿化结节。诱导14 d后对比各组细胞ALP活性。Real-time PCR定量分析各组RA诱导小型猪PDLSCs第21天ALP、OPN、OCN、Col I基因表达情况。结果 纯化后小型猪PDLSCs STRO-1,波形蛋白阳性表达,角蛋白阴性表达,各组RA诱导14 d后,ALP染色阳性,诱导21 d后各诱导组细胞茜素红染色阳性。ALP活性检测显示,小型猪PDLSCs诱导至第14天,ALP活性随RA浓度增高而增高（P<0.001）。Real-time PCR分析成骨相关基因表达结果显示,ALP、OCN基因表达与RA...     

Combination of platelet‐rich plasma within periodontal ligament stem cell sheets enhances cell differentiation and matrix production

The longstanding goal of periodontal therapy is to regenerate periodontal tissues. Although platelet‐rich plasma (PRP) has been gaining increasing popularity for use in the orofacial region, whether PRP is useful for periodontal regeneration is still unknown. The purpose of this study was to determine whether a mixture of periodontal ligament stem cell (PDLSC) sheets and PRP promoted bone regeneration, one of the most important measurement indices of periodontal tissue regenerative capability in vitro and in vivo. In this study, we evaluated the effects of different doses of PRP on the differentiation of human PDLSCs. Then cell sheet formation, extracellular matrix deposition and osteogenic gene expression in response to different doses of PRP treatment during sheet grafting was investigated. Furthermore, we implanted PDLSC sheets treated with 1% PRP subcutaneously into immunocompromised mice to evaluate their bone‐regenerative capability. The results revealed that 1% PRP significantly enhanced the osteogenic differentiation of PDLSCs. Based on the production of extracellular matrix proteins, the results of scanning electron microscopy and the expression of the osteogenic genes ALP, Runx2, Col‐1 and OCN, the provision of 1% PRP for PDLSC sheets was the most effective PRP administration mode for cell sheet formation. The results of in vivo transplantation showed that 1% PRP‐mediated PDLSC sheets exhibited better periodontal tissue regenerative capability than those obtained without PRP intervention. These data suggest that a suitable concentration of PRP stimulation may enhance extracellular matrix production and positively affect cell behaviour in PDLSC sheets. Copyright © 2014 John Wiley & Sons, Ltd.     

Estrogen deficiency leads to impaired osteogenic differentiation of periodontal ligament stem cells in rats

Estrogen deficiency in post-menopausal women is considered as one of the risk factors for periodontal diseases. The periodontal ligament is a connective tissue that connects cementum and alveolar bone to constrain teeth within the jaw. Periodontal ligament stem cells (PDLSCs) isolated from the periodontal ligament can differentiate into many types of specialized cells, including osteoblast-like cells that can be used to regenerate alveolar bone. However, little is known about the effect of estrogen-deficient microenvironment on the osteogenic differentiation of PDLSCs. The aim of this study was to explore the role of estrogen on the potential for osteogenic differentiation of PDLSCs using a rat model of osteoporosis. Three-month-old female Sprague-Dawley rats were divided into two groups (n = 6 for each): ovariectomized (OVX) and sham-operated rats (Sham). Then the characteristics of PDLSCs isolated from these rats were investigated. Real-time PCR analysis showed the lower expression levels of estrogen receptors (ERα and ERβ) mRNAs in PDLSCs of OVX animals compared to Sham control. Mineralization assay demonstrated fewer calcium deposits in PDLSCs from OVX group than those from Sham group. Treatment with 17β-estradiol (E2) significantly enhanced the osteogenic differentiation of PDLSCs from both groups in vitro. Furthermore, by means of lentivirus-mediated siRNA targeting ERα or ERβ, the expression of ERα or ERβ was down-regulated (> 50% reduction), which impaired the estrogen-induced osteogenic differentiation of PDLSCs from both groups (> 50% reduction). These results indicate that estrogen plays an important role in maintaining osteogenic differentiation of PDLSCs, which acts through both ERα and ERβ.     

Simvastatin induces the osteogenic differentiation of human periodontal ligament stem cells

Periodontal ligament stem cells (PDLSCs) are considered as potential mesenchymal stem cell sources for future clinical applications in periodontal regeneration therapy. Simvastation, widely used for lowering serum cholesterol, is known to have a bone stimulatory effect. However, it is not clear whether simvastation affects the differentiation of PDLSCs. This study examined the effects of simvastatin on human PDLSCs in vitro and in vivo. Using the limiting dilution technique, human PDLSCs were isolated and expanded. PDLSCs were cultured with simvastatin (0.01–10 μm ), and the proliferation was measured. The osteogenic differentiation was characterized by alkaline phosphatase (ALP) activity and Alizarin Red‐S staining for calcium deposition. The gene expression levels of osteogenic markers were evaluated by RT‐PCR. In addition, PDLSCs were transplanted into nude mice with ceramic bovine bone powders as carriers to observe the capacity of mineralized tissue formation in vivo. Simvastatin at concentrations <1 μm did not suppress the proliferation of PDLSCs. After the administration of 0.1 μm simvastatin, the expression of ALP, bone sialoprotein, and bone morphogenetic protein‐2 genes were significantly upregulated, and the ALP activity and mineralized nodule formation were significantly higher in the simvastatin‐treated cells than the control cells. In addition, the in vivo transplantation results showed that simvastatin treatment promoted the degree of mineralized tissue formation. Collectively, simvastatin has positive effects on osteogenic differentiation of human PDLSCs in vitro and in vivo. This suggests that simvastatin might be a useful osteogenic induction agent for periodontal bone regeneration.     

Toll样受体4对牙周膜干细胞免疫学特性的影响

背景：Toll样受体4及其配体脂多糖与牙周疾病的发生、发展密切相关,牙周膜干细胞的免疫学特性在牙周组织修复重建、牙周病的治疗中发挥重要作用,而Toll样受体4及其配体对牙周膜干细胞免疫学特性的影响还不清楚。目的：探讨Toll样受体4对牙周膜干细胞免疫学特性的影响。方法：分离、培养牙周膜干细胞,与10 mg/L的Toll样受体4配体脂多糖共同培养3 d。以未经脂多糖处理的牙周膜干细胞作为对照,观察脂多糖处理的牙周膜干细胞能否引起同种异体淋巴细胞的增殖,以及对混合淋巴细胞反应和植物血凝素引起的淋巴细胞增殖的影响。通过建立Transwell培养系统建立牙周膜干细胞＋植物血凝素＋异体外周血单个核细胞的反应体系,测定细胞上清液中的前列腺素E2浓度。在上述反应体系进行中和实验,观察被牙周膜干细胞抑制了的淋巴细胞重新发生增殖的情况。结果与结论：无论是否与脂多糖共培养,牙周膜干细胞都没有引起等量异体外周血单个核细胞增殖,都能够抑制植物血凝素引起的淋巴细胞增殖和混合淋巴细胞反应,但是脂多糖预处理牙周膜干细胞的免疫抑制作用显著低于无脂多糖组。在牙周膜干细胞＋植物血凝素＋异体外周血单个核细胞的反应体系中,前列腺素E2浓度显著升高。中和实验发现,前列腺素E2的拮抗剂吲哚美辛基本恢复了被牙周膜干细胞抑制的淋巴细胞增殖。提示,脂多糖减弱了牙周膜干细胞的免疫抑制特性,该效应由前列腺素E2减少引起。     

Osteogenic potential of rat stromal cells derived from periodontal ligament

Various mesenchymal stromal cells (MSCs) have been applied to regenerative medicine. MSCs derived from periodontal tissue could also be a useful cell source for alveolar bone regeneration. However, only a few attempts of direct comparisons have been made between MSCs from periodontal tissues and those from other somatic tissues. The purpose of this study was to clarify the osteogenic characteristics of mesenchymal stromal cells derived from bone marrow (BMSCs), adipose tissue (ASCs) and periodontal ligament (PDLSCs). BMSCs, ASCs and PDLSCs were isolated from Fisher 344 rats. After 1 week of primary culture, stromal cells were subjected to cell surface analysis and osteogenic differentiation. The cells were subcultured for 2 weeks with and without osteogenic supplements (OS), followed by biochemical and histological analyses. With regard to cell surface antigens, all MSCs were positive for CD29 and CD90 and negative for CD45. With regard to osteogenic differentiation, BMSCs with OS had the highest ALP activity, calcium uptake and osteocalcin content. Without OS, PDLSCs had the highest levels of these bone differentiation markers. RT-PCR analysis and histological analysis showed similar trends. These results indicate that PDLSCs are an ideal candidate for alveolar bone regeneration.     

牙周膜干细胞成骨分化中细胞因子的作用

背景：牙周膜干细胞是牙周组织中的成体干细胞,具有高度增殖、自我更新能力和多分化潜能。促进牙周膜干细胞向成骨细胞分化有助于牙周疾病的治疗。目的：观察胰岛素样生长因子1和成纤维细胞生长因子2对牙周膜干细胞向成骨细胞分化的影响。方法：采用胶原酶消化人牙周膜组织,获得牙周膜干细胞,经体外鉴定、扩增后,通过倒置显微镜、苏木精-伊红染色、流式细胞仪对牙周膜干细胞进行生物学检测。分别在成骨细胞诱导培养液中加入成骨诱导液（对照组）及胰岛素样生长因子1和成纤维细胞生长因子2持续诱导7,14d后,进行碱性磷酸酶染色、碱性磷酸酶活性检测,以及茜素红染色,并用实时定量PCR法检测向成骨细胞分化的标志性基因的表达情况。结果与结论：胰岛素样生长因子1刺激组的碱性磷酸酶活性以及钙化结节明显高于对照组,Runx2、Alp、col-1的mRNA呈高表达;成纤维细胞生长因子2刺激组的碱性磷酸酶活性以及钙化结节也高于对照组,Runx2、Alp、col-1的mRNA表达量也高于对照组。提示胰岛素样生长因子1和成纤维细胞生长因子2在不同程度上促进体外培养的牙周膜干细胞向成骨细胞方向分化。     

Osteogenic differentiated periodontal ligament stem cells maintain their immunomodulatory capacity

Periodontal ligament stem cells (PDLSCs) have great potential for regenerating periodontal ligament tissue, which is involved in attaching teeth to the underlying alveolar bone. Recently, PDLSCs were characterized as having both low immunogenicity and profound immunomodulation abilities. Further, transplanted PDLSCs differentiate into osteoblasts in vivo. In the present study, we investigated the immunological characteristics of osteogenic differentiated PDLSCs. We found that PDLSCs expressed mesenchymal stem cells markers, including STRO‐1 and CD146, but were negative for CD14, CD34 and CD45. RT–PCR indicated that NCAM1, MSX1 and S100A4 were expressed in PDLSCs. The cells underwent osteogenic and adipogenic differentiation when cultured in defined medium. Osteogenic differentiated PDLSCs failed to stimulate allogeneic T cell proliferation and suppressed phytohaemagglutinin‐triggered T cell proliferation. Indomethacin, an inhibitor of prostaglandin E2 (PGE2) production, restored the T cell proliferation inhibited by osteogenic differentiated PDLSCs. These data confirm that osteogenic differentiated PDLSCs have low immunogenicity and demonstrate that they suppress T cell proliferation in vitro through secretion of PGE2. Copyright © 2012 John Wiley & Sons, Ltd.