细胞外信号调节激酶1/2信号转导通路调控牙周膜细胞成骨分化的研究

目的：探索细胞外信号调节激酶（ERK）1/2信号转导通路是否参与调控牙周膜细胞的成骨分化。方法???取体外培养的第3代牙周膜细胞进行研究。实验分为空白对照组、成骨诱导组和实验组（在成骨诱导培养基中加入10?nmol·L－1?ERK1/2磷酸化的抑制剂PD98059）。培养1周和3周后通过定量聚合酶链反应（qPCR）、碱性磷酸酶（ALP）染色和茜素红染色检测其成骨能力。结果?成骨诱导可促进牙周膜细胞中ERK1/2的磷酸化。培养1周后,抑制ERK1/2的磷酸化可上调成骨标志物Runx2、ALP和骨钙蛋白（OCN）的表达,与成骨诱导组相比较,OCN的表达差异具有统计学意义（P<0.05）,Runx2、ALP的表达差异也具有统计学意义（P<0.01）。培养3周后,实验组牙周膜细胞成骨标志物Runx2、ALP和OCN的表达仍较成骨诱导组高,ALP染色和钙结节形成较成骨诱导组强,其中Runx2、ALP的表达差异具有统计学意义（P<0.05）,OCN的表达差异也具有统计学意义（P<0.01）。结论 ERK?1/2信号转导通路参与了调控体外培养的牙周膜细胞的成骨分化。     

釉基质蛋白对人牙周膜细胞粘附、伸展的影响

目的：了解釉基质蛋白对人牙周膜细胞黏附，伸展的影响。方法：改良组织块法培养人牙周膜细胞，固相结合分析方法观察釉基质蛋白对人牙周膜细胞黏附，伸展的影响。结果：实验组PDLC黏附率与对照组无差别，实验组PDLC伸展率高于对照组。结论：EMPs对PDLC黏附无影响，但可促进其伸展。     

釉基质衍生物对人牙周膜干细胞成骨分化的影响

目的研究釉基质衍生物对人牙周膜干细胞增殖和成骨分化的影响并探究其可能的机制。方法原代培养人牙周膜干细胞,经过流式鉴定后选取第3代细胞进行实验。采用CCK-8试剂盒检测不同浓度(0、20、50、100 mg·L^-1)的釉基质衍生物对人牙周膜干细胞增殖的影响;实时荧光定量聚合酶链式反应(qRT-PCR)检测不同浓度(0、20、50、100 mg·L^-1)釉基质衍生物对人牙周膜干细胞成骨分化的影响;通过Trichrome染色和Von Kosa’s染色检测不同浓度(0、20、50、100 mg·L^-1)釉基质衍生物对人牙周膜干细胞胶原合成和矿化结节形成的影响;不同浓度釉基质衍生物和DDK1作用人牙周膜干细胞之后,通过Western blot和qRT-PCR检测β-连环蛋白、RunX2、CaMKⅡ及NLK表达情况。结果釉基质衍生物对人牙周膜干细胞的增殖具有明显的促进作用,并呈现剂量和时间依赖性;釉基质衍生物处理人牙周膜干细胞之后,矿化结节形成和胶原合成显著增多,骨钙素、Ⅰ型胶原、RunX2的表达明显增多;另外,釉基质衍生物处理能显著增加β-连环蛋白、RunX2、CaMKⅡ和NLK的表达,且该作用可被DDK1抑制。结论釉基质衍生物对体外培养的人牙周膜干细胞有促进增殖和成骨分化的作用,其作用可能是通过Wnt/β-连环蛋白实现的。     

釉基质蛋白对牙周膜细胞增殖和碱性磷酸酶活性的影响

目的：探讨釉基质蛋白对于牙周膜细胞增殖和碱性磷酸酶（ALP）活性的影响。方法：采用细胞培养技术,噻唑盐比色测定（MTT）法和酶动力学方法,观察釉基质蛋白对牙周膜细胞的作用。结果：釉基质蛋白组的牙周膜细胞,其增殖活性显著提高,以50mg/L浓度为最佳;其ALP活性也较对照组明显增加,以200mg/L浓度的效果最佳。具有一个合适的剂量范围。结论：釉基质蛋白可促进人牙周膜细胞的增殖和ALP活性。     

Effects of enamel matrix derivative and transforming growth factor-beta1 on human periodontal ligament fibroblasts

AIM: The objective of this study was to evaluate the effects of enamel matrix derivative (EMD), transforming growth factor-beta1 (TGF-beta1), and a combination of both factors (EMD+TGF-beta1) on periodontal ligament (PDL) fibroblasts. MATERIAL AND METHODS: Human PDL fibroblasts were obtained from three adult patients with a clinically healthy periodontium, using the explant technique. The effects of EMD, TGF-beta1, or a combination of both were analysed on PDL cell proliferation, adhesion, wound healing, and total protein synthesis, and on alkaline phosphatase (ALP) activity and bone-like nodule formation. RESULTS: Treatment with EMD for 4, 7, and 10 days increased cell proliferation significantly compared with the negative control (p<0.05). At day 10, EMD and EMD+TGF-beta1 showed a higher cell proliferation compared with TGF-beta1 (p<0.01). Cell adhesion was significantly up-regulated by TGF-beta1 compared with EMD and EMD+TGF-beta1 (p<0.01). EMD enhanced in vitro wound healing of PDL cells compared with the other treatments. Total protein synthesis was significantly increased in PDL cells cultured with EMD compared with PDL cells treated with TGF-beta1 or EMD+TGF-beta1 (p<0.05). EMD induced ALP activity in PDL fibroblasts, which was associated with an increase of bone-like nodules. CONCLUSION: These findings support the hypothesis that EMD and TGF-beta1 may play an important role in periodontal regeneration. EMD induced PDL fibroblast proliferation and migration, total protein synthesis, ALP activity, and mineralization, while TGF-beta1 increased cellular adhesion. However, the combination of both factors did not positively alter PDL fibroblast behaviour.     

Autocrine growth factors in human periodontal ligament cells cultured on enamel matrix derivative

OBJECTIVE: Enamel extracellular matrix proteins in the form of the enamel matrix derivative EMDOGAIN (EMD) have been successfully employed to mimic natural cementogenesis to restore fully functional periodontal ligament, cementum and alveolar bone in patients with severe periodontitis. When applied to denuded root surfaces EMD forms a matrix that locally facilitates regenerative responses in the adjacent periodontal tissues. The cellular mechanism(s), e.g. autocrine growth factors, extracellular matrix synthesis and cell growth, underlying PDL regeneration with EMD is however poorly investigated. MATERIAL AND METHODS: Human periodontal ligament (PDL) cells were cultured on EMD and monitored for cellular attachment rate, proliferation, DNA replication and metabolism. Furthermore, intracellular cyclic-AMP levels and autocrine production of selected growth factors were monitored by immunological assays. Controls included PDL and epithelial cells in parallel cultures. RESULTS: PDL cell attachment rate, growth and metabolism were all significantly increased when EMD was present in cultures. Also, cells exposed to EMD showed increased intracellular cAMP signalling and autocrine production of TGF-beta1, IL-6 and PDGF AB when compared to controls. Epithelial cells increased cAMP and PDGF AB secretion when EMD was present, but proliferation and growth were inhibited. CONCLUSION: Cultured PDL cells exposed to EMD increase attachment rate, growth rate and metabolism, and subsequently release several growth factors into the medium. The cellular interaction with EMD generates an intracellular cAMP signal, after which cells secrete TGF-beta1, IL-6 and PDGF AB. Epithelial cell growth however, is inhibited by the same signal. This suggest that EMD favours mesenchymal cell growth over epithelium, and that autocrine growth factors released by PDL cells exposed to EMD contribute to periodontal healing and regeneration in a process mimicking natural root development.     

釉基质蛋白对人牙囊和牙周膜细胞黏附增殖的影响

目的 比较釉基质蛋白（EMP）对人牙囊细胞（hDFC）和人牙周膜细胞（hPDLC）在钛片表面黏附和增殖能力的影响。方法 分离培养hDFC和hPDLC,双喷砂加酸蚀处理钛片表面。实验分为4组：hDFC＋EMP诱导组、hDFC组、hPDLC＋EMP诱导组、hPDLC组。采用噻唑蓝（MTT）法和细胞免疫荧光染色法,定量分析细胞在钛片表面的黏附和增殖情况,扫描电子显微镜观察细胞在钛片表面1～7 d的生长情况。结果 1～7 d各组间MTT值的差异无统计学意义（P〉0.05）;加有EMP诱导的2组细胞较2组单纯细胞培养组的形状系数（Sf）值更高（P〈0.05）,hDFC组和hPDLC两组间Sf值差异无统计学意义（P〉0.05）,hDFC＋EMP诱导组较hPDLC＋EMP诱导组Sf值高（P〈0.05）。结论 EMP能促进hPDLC和hDFC在钛片表面的黏附,且对hDFC的促进作用更强;但对接种在钛片表面的hPDLC和hDFC短期增殖没有影响。     

Gene profile in periodontal ligament cells and clones with enamel matrix proteins derivative

AIM: Evaluate enamel matrix proteins derivative effect on gene expression profiles in cultured human periodontal ligament cell population and its clones. MATERIAL AND METHODS: Human periodontal ligament (PDL) cells were explanted. Cell cloning was performed and clones classified into fibroblastic (FB) and mineralized tissue forming (MTF) according to their capacity to express alkaline phosphatase and form mineralized tissue. All cell cultures were grown for 7 days, with and without enamel proteins added to the medium. Following RNA extraction, expression profiling was performed by hybridization with a DNA micro-array. Selected genes differed from the control at a significant level smaller than p<0.01. RESULTS: Enamel proteins induced major qualitative changes in mRNA expression in all PDL cell populations, differently affecting the entire PDL cell population and its clones. In the entire PDL cell population, enamel proteins significantly enhanced PDL cell function, with a general effect on enhanced cell functional metabolism. CONCLUSIONS: Enamel proteins enhanced gene expression responsible for protein and mineralized tissue synthesis in the entire PDL population. In the MTF clones, nucleic acid metabolism, protein metabolism and signal transduction related genes were up-regulated, while in the FB clones, up-regulated genes were related to cell adhesion, nucleic acid metabolism and signal transduction.     

Participation of endogenous IGF-I and TGF-beta 1 with enamel matrix derivative-stimulated cell growth in human periodontal ligament cells

Previous studies have provided the biological basis for the therapeutic use of enamel matrix derivative (EMD) at sites of periodontal regeneration. A purpose of this study is to determine effects of EMD on cell growth, osteoblastic differentiation and insulin-like growth factor-I (IGF-I) and transforming growth factor-beta 1 (TGF-beta 1) production in human periodontal ligament cells (HPLC). We also examined participation of endogenous IGF-I and TGF-beta 1 with EMD-stimulated cell growth in these cells. HPLCs used in this study were treated with EMD alone or in combination with antihuman IGF-I antibody (anti-hIGF-I) or anti-hTGF-beta 1, recombinant human bone morphogenetic protein-2 (rhBMP-2), 1,25-dihydroxyvitamin D3[1,25(OH)2D3], rhTGF-beta 1 or rhIGF-I. After each treatment, cell growth, the production of IGF-I and TGF-beta 1 and the expression of osteoblastic phenotypes were evaluated. EMD stimulated cell growth in dose-dependent and time-dependent manners. EMD was also stimulated to express IGF-I and TGF-beta 1 at protein and mRNA levels. The EMD-stimulated cell growth was partially suppressed by cotreatment with anti-hIGF-I or anti-hTGF-beta 1, and cell growth was also stimulated by treatment with rhIGF-I or rhTGF-beta 1. rhBMP-2 stimulated alkaline phosphatase (ALPase) activity and ALPase mRNA expression, and 1,25(OH)2D3 stimulated ALPase and osteocalcin mRNA expression. However, EMD showed no effect on the osteoblastic phenotypes expression. These results demonstrated that EMD has no appreciable effect on osteoblastic differentiation, however it stimulates cell growth and IGF-I and TGF-beta 1 production in HPLC, and that these endogenous growth factors partially relate to the EMD-stimulated cell growth in HPLC.     

釉基质蛋白对人牙周膜细胞总蛋白含量和超微结构的影响

目的：观察釉基质蛋白对人牙周膜细胞总蛋白含量及超微结构的影响。方法：组织块法培养人牙周膜细胞。考马斯亮蓝法测定人牙周膜细胞的总蛋白含量。透射电镜技术观察细胞超微结构。结果：釉基质蛋白质量浓度在50mg／L时即可明显增加人牙周膜细胞的总蛋白含量，l00mg／L时细胞的总蛋白含量增加到最大，此时，细胞的超微结构显示：核仁明显，粗面内质网及高尔基复合体发达。结论：釉基质蛋白能促进人牙周膜细胞核酸及蛋白质的合成活性。     

细胞外信号调节蛋白激酶1/2在介导周期性牵张力对牙周膜细胞成骨分化中的作用

目的 研究周期性牵张力刺激下细胞外信号调节蛋白激酶（ERK）1/2对牙周膜细胞成骨分化的分子调控机制。方法 组织块法培养人牙周膜细胞。采用多通道应力加载系统对细胞施加频率0.5 Hz、振幅10%的周期性牵张力（加力时间1、3、6、12、24 h）,以不加力的细胞作为对照,并分别在加力前应用ERK1/2通路特异性抑制剂U0126以及对细胞转染ERK1/2显性负相变异体（DN-ERK1/2）。采用实时荧光定量聚合酶链式反应（real-time PCR）及蛋白质印迹法研究人牙周膜细胞的基因蛋白水平变化。结果 加力后人牙周膜细胞的p-ERK1/2蛋白水平及骨钙蛋白（OCN） mRNA、骨涎蛋白（BSP）mRNA水平均显著升高,Runt相关基因（Runx）2 mRNA及蛋白水平在加力3、6 h均显著升高。加入抑制剂U0126或细胞转染DN-ERK1/2后,Runx2、OCN、BSP mRNA水平以及Runx2、p-ERK1/2蛋白水平均降低。结论 ERK1/2是周期性牵张力刺激下牙周膜细胞成骨分化的重要分子途径,力学刺激下激活的ERK1/2可能通过提高Runx2蛋白的表达水平而参与成骨基因OCN和BSP的转录表达。     

釉基质蛋白对人牙周膜细胞合成骨桥蛋白、骨涎蛋白的影响

目的:观察釉基质蛋白对体外培养的人牙周膜细胞合成骨桥蛋白、骨涎蛋白能力的影响.方法:乙酸法提取猪釉基质蛋白,改良组织块法原代培养人牙周膜细胞,免疫细胞化学方法和图像分析方法观察细胞合成骨桥蛋白、骨涎蛋白的能力.结果:人牙周膜细胞胞浆骨桥蛋白、骨涎蛋白染色阳性,200、100、50mg/L釉基质蛋白作用下可以使细胞胞浆骨桥蛋白、骨涎蛋白染色不同程度地加深.人牙周膜细胞在釉基质蛋白作用下,最早从第3d开始骨桥蛋白表达增加、从第7d开始骨涎蛋白表达增加.结论:一定浓度的釉基质蛋白在特定的时间可以促进牙周膜细胞合成骨桥蛋白、骨涎蛋白.     

釉基质蛋白对牙周膜细胞增殖和牙骨质相关蛋白基因表达的影响

目的 通过研究釉基质蛋白(enamel matrix proteins,EMP)对人牙周膜细胞增殖及牙骨质相关蛋白基因表达的影响,探讨EMP促进牙骨质形成的机制.方法 分别用质量浓度为0(对照组)、50、100、200、300 mg/L的EMP作用于培养的人牙周膜细胞(periodontal ligament cells,PDLC),在培养的第1、3、5、7天用甲基噻唑基四唑法检测细胞增殖活性;在培养的第7天用荧光实时定量反转录聚合酶链反应法检测各组细胞牙骨质附着蛋白(cementum attachment protein,CAP)和牙骨质蛋白23(cementum protein-23,CP-23)mRNA表达量.结果 EMP质量浓度在50 ～ 200 mg/L范围内可以促进人PDLC增殖,在300 mg/L时抑制细胞增殖;EMP质量浓度为100、200 mg/L时可以显著促进CAP mRNA(分别为4.661 ±0.154、5.923±0.788)和CP-23mRNA的表达(分别为1.222±0.089、3.795±0.640)与对照组(CAP:1.006±0.062,CP-23:1.012±0.163)相比差异均有统计学意义(P＜0.05),且以200 mg/L EMP的促表达效果最佳.结论 EMP在一定浓度范围内能促进人PDLC增殖及CAP和CP-23基因表达,提示EMP可能通过促进细胞增殖和牙骨质相关蛋白的表达促进牙骨质的形成.     

Expression of integrins by human periodontal ligament and gingival fibroblasts and their involvement in fibroblast adhesion to enamel matrix-derived proteins

We showed recently that human periodontal ligament (PDL) and gingival fibroblasts adhere and spread on enamel matrix protein (EMP) coatings. In the present study, we investigated whether this interaction can be attributed to integrin expression. Human PDL and gingival fibroblasts were cultured for periods up to 24 h on EMP coatings, in the presence of synthetic RGD-containing peptide or an antibody against the beta1 integrin subunit. The cells were first cultured for 24 h under serum-free conditions and then cultured on EMP coatings for 48 h. Integrin expression levels were assessed by flow cytometry analysis. It was found that attachment and spreading on EMP was inhibited by the synthetic RGD-containing peptide, but not by a synthetic RGE-peptide. Both PDL and gingival fibroblasts showed expression of the integrin subunits, alpha2, alpha5, beta1, and the integrin, alphavbeta3. Incubation with an antibody against the beta1 subunit significantly inhibited the attachment and spreading of PDL and gingival fibroblasts on EMP coatings. We conclude that integrins are involved in the interaction of PDL and gingival fibroblasts with EMP.     

Evaluation of enamel matrix derivative as an adjunct to non-surgical periodontal therapy

OBJECTIVES: The aim of this study was to evaluate the adjunctive use of enamel matrix derivative (EMD) on periodontal healing following nonsurgical periodontal therapy (scaling and root planing - SRP). MATERIAL AND METHODS: The study was performed as an intraindividual, longitudinal trial of 3 months duration with a double-blinded, split-mouth, controlled, and randomized design. Twenty-two patients with moderate to severe chronic periodontitis were enrolled in the study. In each patient, two sites with pocket depths >/=5 mm and with radiographic angular bone defects >3 mm were selected. Baseline examination included measurement of probing pocket depth (PPD) and clinical attachment levels (CAL). The presence or absence of plaque and bleeding on probing at selected sites was also recorded. Following initial examination, full-mouth SRP was performed. Study sites were then treated with 24% EDTA for 2 min, followed by thorough irrigation with sterile saline. The sites were then randomized. The experimental site received subgingival application of enamel matrix derivative (Emdogain, BIORA AB, Malmo, Sweden). The control site received no additional treatment. At 3 months, all sites were re-examined. The response to therapy in experimental and control sites was evaluated, using change in probing depth and CAL as the primary outcome variables. Statistical analysis (paired t-tests) was used to compare response to treatment in control versus experimental sites. RESULTS: Statistically significant changes in PPD and CAL were seen in both treatment groups from baseline to 3 months. The mean PPD reduction was 2.3+/-0.5 mm for control sites and 2.0+/-0.3 mm for experimental sites. The mean CAL gain was 1.8+/-0.4 mm for control sites, and 1.4+/-0.3 mm for experimental sites. Statistical analysis, however, revealed no significant difference in PPD reduction or CAL gain between experimental and control groups (p>0.4). In addition, no difference was found between treatment groups in bleeding or plaque indices at 3 months. CONCLUSION: The findings from the present study do not support the use of EMD during routine, nonsurgical debridement of periodontal pockets as measured 3 months post SRP.