牙周膜干细胞与牙周组织的再生

背景：牙周组织再生过程中再生细胞数量和生物学功能的不足是造成组织再生困难的主要原因。 目的：就近年来牙周膜干细胞在牙周组织再生中的研究进展及未来展望作一综述。 方法：由第一作者检索Pubmed 数据库(http://www.ncbi.nlm.nih.gov/pubmed)、中国知网数据库(http://www. cnki.net/)2000年1月至2012年7月 有关牙周膜干细胞分离、鉴定、相关细胞因子等方面的文献,英文检索词为“periodontal ligamentstem cell”,中文检索词为“牙周膜,干细胞”。排除重复性研究,最终纳入26 篇文献进行综述。 结果与结论：利用组织工程的方法,将牙周膜干细胞作为牙周组织再生的种子细胞,在体外培养扩增后移植至缺损区,可有效增进牙周附着结构的再生并缩短愈合周期。对牙周膜干细胞的研究已成为目前牙组织工程领域中的重点课题。     

牙周膜干细胞的研究进展

背景：从牙周膜组织中分离出的牙周膜干细胞被认为是牙周组织工程的首选种子细胞,有自我更新能力,能分化形成牙周的3种组织：牙槽骨、牙周膜和牙骨质。 目的：就近年来牙周膜干细胞的分离、鉴定、相关细胞因子等方面进行简要综述。 方法：由第一作者检索Pubmed 数据库(http://www.ncbi.nlm.nih.gov/pubmed)、中国知网数据库(http://www. cnki.net/)2004-01/2010-09有关牙周膜干细胞分离、鉴定、相关细胞因子等方面的文献,英文检索词为“periodontal ligament stem cell”,中文检索词为“牙周膜,干细胞”。排除重复性研究,最终纳入35篇文献进行综述。 结果与结论：牙周膜干细胞是一种很有潜力的牙周组织工程种子细胞,能构建组织工程牙周膜,促进牙周缺损的修复。随着研究的深入,影响牙周膜干细胞生物性能的因素逐渐被发现,但其研究还有待进一步完善。     

活性氧影响牙周炎发生发展及牙周组织再生

背景：活性氧在牙周炎发生发展和牙周组织再生过程中发挥双刃剑作用，低浓度的活性氧诱导牙周膜成纤维细胞的分化，过量的活性氧会造成牙周组织损伤。炎症发生时，牙周组织中的活性氧聚集，通过多种细胞信号通路或通过氧化还原反应诱导细胞和组织的损伤。目的：对活性氧在牙周炎发生发展及牙周组织再生中的双刃剑效果进行综述，为临床治疗牙周炎及促进牙周组织再生提供潜在靶点及治疗思路。方法：通过检索1990年4月至2023年4月PubMed及中国知网数据库，英文检索词为“periodontal tissue engineering,periodontal defect,regeneration of periodontal tissue,chronic periodontitis,reactive oxygen species,oxidative stress,antioxidative stress,oxidative injuries,free radicals,reactive nitrogen species”，中文检索词为“牙周组织工程，牙周缺损，牙槽骨丧失，牙周组织再生，牙周炎，破骨细胞，氧化应激，抗...     

间充质干细胞促进关节软骨的修复与再生

背景：关节软骨损伤后,软骨组织几乎没有修复能力,关节软骨损伤的修复一直是临床工作的难点。 目的：探讨修复关节软骨损伤的干细胞种类及其生物学特性,明确干细胞在修复关节软骨损伤中的作用及优缺点。 方法：由第一作者检索1998至2015年PubMed数据及CNKI中国期刊全文数据库,英文检索词“Articular cartilage injury,Mesenchymal stem cells ,regeneration”;中文检索词“关节软骨损伤,间充质干细胞,再生”,纳入47篇文献进行分析。 结果与结论：关节软骨损伤最有效的修复方案是以细胞为基础的治疗方法,来源于骨髓、脂肪及脐血的间充质干细胞均有较强的成软骨特性和克隆能力。骨髓间充质干细胞具有更高的分化潜能,对软骨缺损有修复作用,来源于脐血的间充质干细胞致瘤性低,脂肪源性干细胞的生长增殖速度更快。干细胞复合天然载体材料如胶原、明胶、纤维蛋白和藻酸盐等可促进细胞黏附、分化和增殖,以此构建组织工程软骨将有效修复关节软骨缺损。 中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程      

脂肪干细胞诱导分化的现状及前景

背景：脂肪干细胞是由中胚层发育而来的多能干细胞,在特殊的生长因子和环境等诱导培养条件下,可以向不同的谱系分化。 目的：详细阐述脂肪干细胞诱导分化的条件及鉴定方法。 方法：应用计算机检索万方数据库及PubMed数据库2005至2014年10年间的文献,中文检索词为“脂肪干细胞,诱导,分化”;英文检索词为“adipose derived stem cells,differentiation”。依据纳入排除标准选择37篇文献进行归纳总结。 结果与结论：脂肪干细胞在抗坏血酸、胰岛素、地塞米松、转化生长因子β作用下可向软骨细胞分化;成脂诱导液的配方包括3-异丁基-1-甲基黄嘌呤(IBMX)、胰岛素、地塞米松、吲哚美辛;成骨分化常用的诱导剂包含地塞米松或维生素D3、抗坏血酸,β-甘油磷酸钠;碱性成纤维细胞生长因子、表皮生长因子及维生素B27可联合应用诱导脂肪干细胞成神经分化;向心肌细胞分化普遍应用的诱导因子是5-氮杂胞苷;血管内皮生长因子和碱性成纤维细胞生长因子共同作用可以诱导脂肪干细胞向血管内皮细胞分化。随着分子生物学和细胞生物学的迅速发展,脂肪干细胞的分化研究也会更加深入,在目前对脂肪干细胞诱导分化现象观察的基础上,应加强对其内在的分子机制及调控脂肪干细胞可塑性的基因和蛋白的研究。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

不同因子影响骨髓间充质干细胞的多向分化

背景：在组织工程领域,关于骨髓间充质干细胞定向诱导分化的研究越来越多,但是细胞培养基中不同成分会对骨髓间充质干细胞的体外增殖分化产生影响。 目的：针对培养基中不同因子对骨髓间充质干细胞定向诱导分化的作用加以综述。 方法：第一作者应用计算机检索1998年1月至2012年4月Pubmed数据库及万方数据库。检索英文关键词为“bone marrow mesenchymal stromal cells, cell culture medium, differentiation”,中文关键词为“骨髓间充质干细胞,细胞培养,定向诱导分化”,纳入有关不同因子对骨髓间充质干细胞向成骨细胞、软骨细胞和脂肪细胞定向诱导分化作用的文献,排除重复研究。 结果与结论：计算机初检共得到184篇文献,根据纳入排除标准,对其中30篇文献进行综述。大体说来,骨髓间充质干细胞向成骨分化的主要因子有地塞米松、转化生长因子、维生素C、维生素D3、β-甘油磷酸钠及乙烯雌酚等;向软骨分化的主要因子有地塞米松、转化生长因子、维生素C、胰岛素样生长因子及成纤维细胞生长因子等;向脂肪细胞转化的主要因子有地塞米松、3-异丁基-1-甲基黄嘌呤、胰岛素和消炎痛等,但是其中一些因子的作用机制及不良反应还不明确,需要进一步的研究与验证。同时,骨髓间充质干细胞在骨髓中的含量较低,不同的分离方法会导致不同的分离率,因此如何选取一种分离率高的分离方法仍有待研究。     

骨组织工程中干细胞的研究与应用

背景：是否可以通过改进对已知的可以分化成骨的干细胞的培养方式或者寻找到新的干细胞,为骨组织工程找到更为合适的种子细胞。 目的：从干细胞的分离培养、生物学特性及标志物等方面对各类干细胞的在骨组织工程中的应用进行综述。 方法：以英文检索词为“bone tissue engineering,seed cells,stem cell,osteoblast differentiation”及中文检索词为“骨组织工程,种子细胞,干细胞,成骨分化”,由第一作者检索1995年至2012 年PubMed 数据库及中国知网中文科技数据库,查阅近年种子细胞相关文献,最终保留50篇文献,从分离培养方法、基本特性及在骨组织工程中的应用3方面进行综述。 结果与结论：文章分别对各类干细胞(包括：胚胎干细胞、骨髓间充质干细胞、滑膜间充质干细胞、脐带间充质干细胞和脐带血间充质干细胞、外周血来源的多潜能间充质干细胞、脂肪干细胞、子宫内膜基质干细胞、人羊膜基质细胞、牙髓干细胞)的分离方法、生物学特性、标志物等相关实验研究进行了探讨。目前用于分离纯化骨髓间充质干细胞的方法主要有4 种：密度梯度离心法、全骨髓贴壁培养法、流式细胞仪分离法和免疫磁珠法。研究证实各类干细胞在特定条件下均有分化成骨的能力。     

釉基质蛋白组成及诱导细胞分化研究进展☆○

背景：研究表明,釉基质蛋白不仅能够诱导牙周组织再生,还对其他类型的细胞也有不同程度的作用效果。 目的：综述釉基质蛋白的组成成分及其在诱导干细胞分化方面的研究进展,深入解析釉基质蛋白的生物模拟作用及其可能的机制。 方法：应用计算机检索中国生物医学文献数据库,中国知网,万方、维普数据库1997-01/2011-12相关文献,检索词“釉基质蛋白,分化”限定文献语言种类为中文。同时计算机检索PubMed,EBSCO HOST数据库1997-01/2011-12相关文献,检索词“Enamel matrix derivative,Emdogain®,differentiation”,限定文献种类为英文。手工检索美国化学文摘数据库,荷兰医学文摘,进行文献初检。筛选后纳入38篇文章进行综述。 结果与结论：釉基质蛋白组成成分复杂,包含有多种蛋白和类生长因子物质。釉基质蛋白具有生物模拟效果,对不同类型的干细胞具有不同程度的促进或抑制分化作用。提示釉基质蛋白将有可能不仅应用于牙周疾病的治疗,还可能应用于其他组织再生领域。      

细胞因子与干细胞骨软骨分化的调节

背景：软骨修复尤其是伴软骨下骨的修复是骨关节组织工程修复的研究重点。近些年,随着人们对细胞因子研究的不断深入,寻找一种合适的细胞因子,诱导细胞骨软骨分化备受关注。 目的：综述细胞因子对干细胞骨软骨分化调节的影响。 方法：应用计算机检索2000年1月至2011年12月PubMed数据库相关文章,检索词为“chondrification,cytokine,stem cells,tissue engineering”,并限定文章语言种类为English。同时计算机检索2000年1月至2011年12月万方医学数据库相关文章,检索词为“软骨形成,细胞因子,干细胞,组织工程”,并限定文章语言种类为中文。最终纳入符合标准的文献32篇。 结果与结论：诱导干细胞成骨、成软骨分化的成功与否与诱导因子息息相关,尤其是Wnt信号通路、转化生长因子β超家族途径在干细胞成骨、成软骨分化调节过程发挥重要作用。随着对干细胞分化过程中各种调控因素的深入研究,将为体外培养和诱导干细胞的定向分化发育创造更好的条件。     

胎盘间充质干细胞的应用研究

背景：胎盘间充质干细胞因其具有来源广泛、免疫原性低、不涉及伦理问题等优点成为种子细胞的新来源。 目的：阐述胎盘间充质干细胞的来源、生物学特性及应用最新研究进展。 方法：检索 PubMed、ScienceDirect、OvidSP、CNKI 数据库相关文章,检索时限为2003至 2015年,英文检索词为“Placenta,Mesenchymal stem cells,The placenta mesenchymal stem cells, Cell transplantation , Application mechanism”,中文检索词为“胎盘,间充质干细胞,胎盘间充质干细胞,细胞移植,应用机制”,从中筛选出与主题相关且论据可靠的部分文献,最终纳入57篇文章进行归纳综述。 结果与结论：目前已成功分离培养出胎盘间充质干细胞,并对其生物学特性进行研究,证明其具有干细胞源性及多向分化潜能。目前有较多关于胎盘间充质干细胞应用于实验动物及临床的研究,在骨组织工程、血管再生及神经组织等修复过程中均显示出了巨大的潜力,但胎盘间充质干细胞的具体应用机制目前尚不清楚,尚处于探索阶段,在胎盘间充质干细胞广泛应用于临床之前,仍有许多问题有待进一步研究明确,以确保其安全性和有效性。  中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程     

引导组织再生联合植骨修复根分叉病变的Meta分析

BACKGROUND: Numerous experimental and clinical observations have shown new attachment formation in the periodontium by guided tissue regeneration. OBJECTIVE: To evaluate the efficacy of guided tissue regeneration combined with bone grafting for the treatment of root furcation defects. METHODS: A computer-based online search combined with manual retrieval was conducted up to 2015 to screen the relevant English and Chinese literatures addressing guided tissue regeneration, bone grafting, and root furcation defects. Vertical and horizontal probing depth and attachment loss were analyzed. Meta-analysis was performed using Stata/SE version 12.0 software by extracting data from the relevant articles. Moreover, the publication bias was tested. RESULTS AND CONCLUSION: The meta-analysis results showed that at 6 months after treatment, the alterations in vertical probing depth and periodontal attachment were significantly increased after guided tissue regeneration compared with open-flap debridement (P < 0.000 01); the alterations and increment in the periodontal attachment were significantly increased after combined treatment of guided tissue regeneration and bone grafting compared with open-flap debridement (P < 0.000 01); the reduction in the vertical and horizontal probing depth and the increment in periodontal attachment were significantly increased after combined treatment of guided tissue regeneration and bone grafting compared with guided tissue regeneration (P < 0.000 01 or P = 0.01). At 12 months after treatment, the reduction in vertical probing depth and the increment in attachment loss were significantly increased after combined treatment of guided tissue regeneration and bone grafting compared with guided tissue regeneration (P < 0.000 01). These results indicate that the guided tissue regeneration combined with bone grafting in the treatment of root furcation defects is superior to guided tissue regeneration or open-flap debridement. In addition, in the latter two therapies, guided tissue regeneration shows a better therapeutic effect. However, the therapeutic effects of various types of regenerated membranes and bone grafts need further in-depth study to define the optimal treatment strategy. 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

周期性张应力下人牙周膜成纤维细胞结缔组织生长因子的表达

背景：前期研究发现,周期性张应力在一定时间内可以诱导人牙周膜成纤维细胞增殖。 目的：观察周期性张应力对人牙周膜成纤维细胞表达结缔组织生长因子的影响;明确JNK、p38MAPK、PI3K信号通路在周期性张应力诱导人牙周膜成纤维细胞表达结缔组织生长因子过程中的作用。 方法：采用多通道细胞牵张应力加载系统对体外培养的人牙周膜成纤维细胞分别给予周期性张应力刺激1,6,12,24 h,并以未加力组为对照组。对加力12 h的细胞分别添加JNK、p38MAPK、PI3K信号通路特异性抑制剂预处理,并与未加抑制剂的细胞作对比。应用ELISA法检测培养细胞分泌到上清液中的结缔组织生长因子蛋白;应用荧光定量PCR技术检测细胞结缔组织生长因子mRNA的表达。 结果与结论：加载周期性张应力组与对照组相比较,1 h人牙周膜成纤维细胞表达结缔组织生长因子开始增强、6 h表达明显增强,12 h达最高峰值、24 h表达开始下降。加入JNK信号通路特异性抑制剂后,人牙周膜成纤维细胞表达结缔组织生长因子出现下降;而加入p38MAPK信号通路和PI3K信号通路的特异性抑制剂后结缔组织生长因子表达未发生明显改变。提示在一定时间范围内,周期性张应力引起结缔组织生长因子mRNA与蛋白水平的表达与时间呈依赖性升高;其后随着时间的延长,结缔组织生长因子的表达则开始下降。周期性张应力通过JNK通路的介导调控人牙周膜成纤维细胞结缔组织生长因子的表达。中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

引导骨再生技术在上前牙种植修复中的效果

背景：膜引导骨再生技术是利用膜的机械屏障原理,阻挡软组织长入种植体周骨缺损,使成骨细胞在膜下空间中优势生长,形成新骨充填骨缺损。 目的：于上前牙种植中应用引导骨再生技术,观察其对修复效果的影响。 方法：74例单颗前牙种植成功患者按照随机数字表法分组为对照组与观察组,各37例。对照组采用上前牙二期种植,但未行骨增量;观察组采用引导骨再生技术实施上前牙种植,待其种植体初期稳定后植入人工骨粉。于术后当天、种植牙负重6个月、12个月比较2组患者软组织红色美学指数及种植体周围骨水平。 结果与结论：2组患者种植牙负重6,12个月红色美学指数值较基线水平比较均明显提高(P < 0.05),但2组间比较差异无显著性意义(P > 0.05)。种植牙负重12个月时,除唇侧龈缘水平和牙槽突外形外,2组患者红色美学指数其余各项指数值较基线水平均明显升高(P < 0.05);但2组间红色美学指数各项指数值比较(P > 0.05)。种植牙负重12个月时,2组患者种植体边缘骨水平值比较差异无显著性意义(P > 0.05)。结果说明相比正常骨组织种植修复来说,临床应用引导骨再生技术于上前牙种植中修复可取得较好效果,且两者修复效果无明显差异性。  中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

Estrogen regulates osteogenic differentiation of human periodontal ligament stem cells via Wnt/beta-catenin signaling pathway北大核心

BACKGROUND: Estrogen can promote the osteogenic differentiation of human periodontal ligament stem cells (hPDLSCs), but the molecular mechanism is unclear. OBJECTIVE: To study the regulatory effect of estrogen on the osteogenic differentiation of hPDLSCs via Wnt/β-catenin signaling pathway. METHODS: The hPDLSCs were isolated and purified by digestion method combined with limited dilution clone method. Three experimental groups were set as follows: osteogenic induction only (control group); 1×10-7 mol/L estrogen with osteogenic induction (estrogen group); and 100 µg/L Wnt3a protein with osteogenic induction (Wnt3a group). Alkaline phosphatase activity was detected at 1, 3, 5, 7 days of osteogenic induction. Western blot was used to detect the expression of Wnt/β-catenin signaling pathway related proteins β-catenin, P-GSK-3β, GSK-3β, CyclinD1 and osteoblast-related proteins Runx2 and OCN after 7 days of osteogenic induction. RESULTS AND CONCLUSION: The activity of ALP in all groups increased with time. The expression level of ALP in the estrogen group and Wnt3a group was higher than that in the control group at 1, 3, 5 and 7 days of induction (P < 0.05), while there was no significant difference between the former two groups (P > 0.05). The western blot results showed that the expression levels of β-catenin, P-GSK-3β, CyclinD1, Runx2 and OCN in the estrogen group and Wnt3a group were higher than those in the control group (P < 0.05), while the expression of GSK-3β was lower than that in the control group (P < 0.05). But there were no differences in the expression of Wnt/β-catenin signaling pathway related proteins and mid-late osteogenic markers between estrogen group and Wnt3a group (P > 0.05). To conclude, estrogen can enhance the osteogenic differentiation of hPDLSCs, and the underlying mechanism is likely to activate the Wnt/β-catenin signaling pathway in activated hPDLSCs exposed to estrogen. © 2018, Journal of Clinical Rehabilitative Tissue Engineering Research. All rights reserved.     

左旋聚乳酸羟基磷灰石材料上人牙周膜细胞的生长

BACKGROUND: In constructing tissue-engineered periodontium in vitto, the effective combination of seed cells with scaffold materials is the key to promote the quality of tissue-engineered periodontium, in which human periodontal ligament cells are commonly used. OBJECTIVE: To explore the growth of human periodontal ligament cells on the poly-L-lactic acid hydroxyapatite. METHODS: Human periodontal ligament cells were isolated and cultured in vitro, and passage 3 cells were chosen to be randomly divided into two groups: cells cultured alone as control group, and cultured with poly-L-lactic acid hydroxyapatite as experimental group. After 1, 2 and 3 days, alkaline phosphatase activity and expression of type III collagen in the two groups were detected, and the cell growth curve was depicted using MTT method. RESULTS AND CONCLUSION: By immunohistochemical staining, cultured cells were positive for vimentin and alkaline phosphatase staining and negative for anti-keratin staining, indicating that the cells were identified as human periodontal ligament cells. By MTT method, there was no significant difference in the absorbance value of two groups at different time points (P > 0.05). And after 1, 2 and 3-day co-culture, the alkaline phosphatase activity levels showed no significant difference between two groups (P > 0.05). Besides, no significant difference in the absorbance value of type III collagen was found in the two groups (P > 0.05). To conclude, the human periodontal ligament cells can grow and proliferate well on the poly-L-lactic acid hydroxyapatite scaffold with no cytotoxicity.     

人牙周膜细胞在左旋聚乳酸/羟基磷灰石生物材料上的生长观察

目的观察电纺左旋聚乳酸/羟基磷灰石(PLLA/HA)生物材料(简称生物材料)的生物相容性,并以人牙周膜细胞作为种子细胞与生物材料复合培养,探索该生物材料用于人牙周组织再生的可能性。方法用电纺法制备PLLA/HA纤维生物材料;组织块法分离培养人牙周膜细胞,并用免疫组织化学方法鉴定;MTT法评价生物材料的生物相容性;将人牙周膜细胞与生物材料复合培养,用扫描电镜进行观察;将转染人腺病毒介导的绿色荧光蛋白的人牙周膜细胞与生物材料复合培养,用激光扫描共焦显微镜观察。结果成功分离了人牙周膜细胞,波形蛋白染色阳性确定该细胞来源于中胚层;MTT法检测人牙周膜细胞在生物材料上的增殖状况与正常培养基本一致;扫描电镜下可见细胞在生物材料上生长旺盛、充分伸展;激光扫描共焦显微镜下可见人牙周膜细胞沿生物材料呈纤丝生长,表现出一定的三维结构。结论电纺PLLA/HA生物材料具有三维空间网状结构和良好的生物相容性,与人牙周膜细胞复合培养有利于细胞的生长、贴附和增殖,并呈现一定的立体结构,为人牙周组织再生提供了实验依据。     

不锈钢麻花丝牙周夹板在牙周病松动牙治疗中的应用

目的探索不锈钢麻花牙周夹板在牙周病松动牙康复治疗中的应用。方法在牙周基础治疗的基础上,采用不锈钢麻花丝与光固化树脂联合制作牙周夹板治疗牙周病松动牙。结果 26例中、晚期牙周病患者松动牙固定,经6~18月复查,松动牙固定效果好,牙周病发展得到控制。结论利用不锈钢麻花丝与光固化树脂联合制作的牙周夹板强度好,美观适用。     

Investigation of dental pulp stem cells isolated from discarded human teeth extracted due to aggressive periodontitis

Recently, human dental pulp stem cells (DPSCs) isolated from inflamed dental pulp tissue have been demonstrated to retain some of their pluripotency and regenerative potential. However, the effects of periodontal inflammation due to periodontitis and its progression on the properties of DPSCs within periodontally compromised teeth remain unknown. In this study, DPSCs were isolated from discarded human teeth that were extracted due to aggressive periodontitis (AgP) and divided into three experimental groups (Groups A, B and C) based on the degree of inflammation-induced bone resorption approaching the apex of the tooth root before tooth extraction. DPSCs derived from impacted or non-functional third molars of matched patients were used as a control. Mesenchymal stem cell (MSC)-like characteristics, including colony-forming ability, proliferation, cell cycle, cell surface antigens, multi-lineage differentiation capability and in vivo tissue regeneration potential, were all evaluated in a patient-matched comparison. It was found that STRO-1- and CD146-positive DPSCs can be isolated from human teeth, even in very severe cases of AgP. Periodontal inflammation and its progression had an obvious impact on the characteristics of DPSCs isolated from periodontally affected teeth. Although all the isolated DPSCs in Groups A, B and C showed decreased colony-forming ability and proliferation rate (P < 0.05), the decreases were not consistent with the degree of periodontitis. Furthermore, the cells did not necessarily show significantly diminished in vitro multi-differentiation potential. Only DPSCs from Group A and the Control group formed dentin-like matrix in vivo when cell-seeded biomaterials were transplanted directly into an ectopic transplantation model. However, when cell-seeded scaffolds were placed in the root fragments of human teeth, all the cells formed significant dentin- and pulp-like tissues. The ability of DPSCs to generate dental tissues decreased when the cells were isolated from periodontally compromised teeth (P < 0.05). Again, increased periodontal destruction was not necessarily followed by a decrease in the amount of dentin- and pulp-like tissue formed. These findings provide preliminary evidence that periodontally compromised teeth might contain putative stem cells with certain MSC properties, as long as the vitality of the pulp has not been totally damaged. Whether these cells can serve as a source of autologous multipotent MSCs for clinical regenerative therapies warrants further investigation with larger sample sizes and various types of periodontitis.     

正畸牙移动中牙周膜的力学-生物学行为研究进展

正畸牙移动（OTM）是一个相当复杂的力学-生物学过程,是通过力学手段使牙周组织发生改建而实现的.牙周膜作为连接牙槽骨与牙骨质的结缔组织,在对正畸力的感受和传导中起着非常重要的作用;同时,其在OTM过程中敏感的生物力学反应是介导和调控牙周组织发生改建的关键因素.就牙周膜在OTM过程中的具体作用及其力学-生物学行为作一综述.结合近年来最新的研究成果,从组织、细胞及分子水平阐明了牙周膜在OTM中的力学响应及生物学行为机制.     

Influence of Aging on Biological Properties of Periodontal Ligament Cells

The majority of patients eligible for periodontal regenerative therapies are aged subjects. Since periodontal ligament cells (PDLC) are essential for periodontal regeneration, the aim of the present study was to determine the effect of cellular aging on PDLC, including genes associated with extracellular matrix metabolism and growth-associated factors. PDLC cultures were obtained from subjects aged 15 to 20 years and subjects aged more than 60 years. Proliferation, cell viability, mineralization assays, and mRNA levels were assessed for type I and III collagen, platelet-derived growth factor (PDGF)-1, basic fibroblast growth factor (bFGF), metalloproteinase (MMP)-2 and-8, and tissue inhibitor of metalloproteinases (TIMP)-1 and-2. Data analysis demonstrated that aging negatively influenced cell proliferation and mineral nodule formation (p < 0.05). Gene expression analysis further showed that mRNA levels for bFGF, PDGF-1, and TIMP-2 were not affected by aging (p > 0.05). In addition, mRNA levels for type I and III collagen were significantly lower in aged cells (p < 0.05), whereas MMP-2 and-8 and TIMP-1 mRNA levels were higher (p < 0.05). Within the limits of the present study, data analysis suggests that aging modulates important biological properties of periodontal ligament cells, diminishes the potential for mineral nodule formation, and favors extracellular matrix degradation.