Modification of tooth development by heat shock protein 60

several heat shock proteins have been investigated in relation to tooth development, no available information is available about the spatial and temporal expression pattern of heat shock protein 60 （Hsp 60）. To characterize Hsp 60 expression in the structures of the developing tooth germ, we used Western blotting, immunohistochemistry and in situ hybridization. Hsp 60 was present in high amounts in the inner and outer enamel epithelia, enamel knot （EK） and stratum intermedium （SI）. Hsp 60 also appeared in odontoblasts beginning in the bell stage. To obtain data on the possible effect of Hsp 60 on isolated lower incisors from mice, we performed in vitro culturing. To investigate the effect of exogenous Hsp 60 on the cell cycle during culturing, we used the 5-bromo-2- deoxyuridine （BrdU） incorporation test on dental cells. Exogenously administered Hsp 60 caused bluntness at the apical part of the 16.5-day-old tooth germs, but it did not influence the proliferation rate of dental cells. We identified the expression of Hsp 60 in the developing tooth germ, which was present in high concentrations in the inner and outer enamel epithelia, EK, SI and odontoblasts. High concentration of exogenous Hsp 60 can cause abnormal morphology of the tooth germ, but it did not influence the proliferation rate of the dental cells. Our results suggest that increased levels of Hsp 60 may cause abnormalities in the morphological development of the tooth germ and support the data on the significance of Hsp during the developmental processes.

The Effect of Simvastatin on mRNA Expression of Transforming Growth Factor-β1,Bone Morphogenetic Protein-2 and Vascular Endothelial Growth Factor in Tooth Extraction Socket

Aim To determine the effect of local simvastatin application on the mRNA expression level of transforming growth factor-β1 （TGF-β1）, bone morphogenetic protein-2 （BMP-2） and vascular endothelial growth factor （VEGF） in the tooth sockets of rat. Methodology Forty-eight male Wistar rats were randomly divided into experimental and control groups （n=24）. Polylactic acid/polyglycolic acid copolymer carriers, with or without simvastatin, were implanted into extraction sockets of right mandibular incisors. The expression of TGF-β1, BMP-2 and VEGF mRNA was determined by in situ hybridization in the tooth extraction socket at five days, one week, two weeks and four weeks after implantation. Results The fusiform stroma cells in the tooth extraction socket began to express TGF-β1, BMP-2 and VEGF mRNA in both experimental and control groups from one week after tooth extraction until the end of experiment. The expression of TGF-131 and BMP-2 mRNA in the experimental group was significantly up-regulated after one, two and four weeks, and expression of VEGF mRNA was significantly increased after one and two weeks compared with that in the control group. Conclusion The findings indicate that local administration of simvastatin can influence alveolar bone remodeling by regulating the expression of a school of growth factors which are crucial to osteogenesis in the tooth extraction socket.

Low-intensity pulsed ultrasound reduces alveolar bone resorption during orthodontic treatment via Lamin A/C-Yes-associated protein axis in stem cells

BACKGROUND The bone remodeling during orthodontic treatment for malocclusion often requires a long duration of around two to three years,which also may lead to some complications such as alveolar bone resorption or tooth root resorption.Low-intensity pulsed ultrasound(LIPUS),a noninvasive physical therapy,has been shown to promote bone fracture healing.It is also reported that LIPUS could reduce the duration of orthodontic treatment;however,how LIPUS regulates the bone metabolism during the orthodontic treatment process is still unclear.AIM To investigate the effects of LIPUS on bone remodeling in an orthodontic tooth movement(OTM)model and explore the underlying mechanisms.METHODS A rat model of OTM was established,and alveolar bone remodeling and tooth movement rate were evaluated via micro-computed tomography and staining of tissue sections.In vitro,human bone marrow mesenchymal stem cells(hBMSCs)were isolated to detect their osteogenic differentiation potential under compression and LIPUS stimulation by quantitative reverse transcription-polymerase chain reaction,Western blot,alkaline phosphatase(ALP)staining,and Alizarin red staining.The expression of Yes-associated protein(YAP1),the actin cytoskeleton,and the Lamin A/C nucleoskeleton were detected with or without YAP1 small interfering RNA(siRNA)application via immunofluorescence.RESULTS The force treatment inhibited the osteogenic differentiation potential of hBMSCs;moreover,the expression of osteogenesis markers,such as type 1 collagen(COL1),runt-related transcription factor 2,ALP,and osteocalcin(OCN),decreased.LIPUS could rescue the osteogenic differentiation of hBMSCs with increased expression of osteogenic marker inhibited by force.Mechanically,the expression of LaminA/C,F-actin,and YAP1 was downregulated after force treatment,which could be rescued by LIPUS.Moreover,the osteogenic differentiation of hBMSCs increased by LIPUS could be attenuated by YAP siRNA treatment.Consistently,LIPUS increased alveolar bone density and decreased vertical bone absorption in vivo.The decreased expression of COL1,OCN,and YAP1 on the compression side of the alveolar bone was partially rescued by LIPUS.CONCLUSION LIPUS can accelerate tooth movement and reduce alveolar bone resorption by modulating the cytoskeleton-Lamin A/C-YAP axis,which may be a promising strategy to reduce the orthodontic treatment process.

剔除小鼠神经微管运动蛋白Kif1b基因导致类似Charcot-Marie-Tooth病动物模型

目的研究杂合子小鼠Kiflb基因剔除后导致的表现型,探讨其作为类似Charcot-Marie-Tooth (CMT)病动物模型的可行性。方法用Southern blotting和PCR检测同源重组和基因型,Western blotting测定杂合子KIF1B蛋白表达量,行为学实验观察其表现型。结果杂合子Kif1b基因剔除小鼠的KIF1B蛋白表达量减少了一半以上,行为学实验结果表明,杂合子基因剔除小鼠在运动和感觉方面均有异常。Rota-rod实验,Rod walking实验和Wire hanging实验中,野生型小鼠的停留时间均明显长于Kif1b基因剔除小鼠。同时,杂合子Kif1b基因剔除小鼠在热板实验和福尔马林实验中,表现出对温度觉和痛觉反应的迟钝,其反应时间与野生型小鼠相比明显延长,反应强度降低。结论杂合子Kif1b基因剔除小鼠的表现型与人类腓骨肌萎缩症相似,作为疾病模型具备可行性。

周围髓鞘蛋白22基因重复异常的Charcot-Marie-Tooth病患者临床表型分析

目的分析Charcot-Marie-Tooth病(CMT)周围髓鞘蛋白22(PMP22)基因重复异常患者临床症状、体征和电生理特点。方法61例CMT患者,14例为有家族史的先证者,47例为散发患者,PCR-双酶切方法检测周围髓鞘蛋白22(PMP22)基因重复异常片断,详细问病史和神经系统查体、部分患者行腰穿和腓肠神经病理检查。结果检出PMP22基因重复异常患者41例,主要临床特点为以双足背屈力弱为主的双下肢无力,伴双侧小腿为主的四肢远端萎缩,80%伴上肢远端肌萎缩,97%踝反射减弱或消失,68%伴有深浅感觉障碍,少数脑脊液蛋白增高,神经电生理和腓肠神经病理提示为脱髓鞘伴有轴索变性。结论PMP22基因重复异常的CMT患者的临床表现为以下肢远端肌萎缩和肌无力为主,伴有感觉异常;周围神经髓鞘和轴索均有病变。

Methods for studying tooth root cementum by light microscopy

The tooth root cementum is a thin, mineralized tissue covering the root dentin that is present primarily as acellular cementum on the cervical root and cellular cementum covering the apical root. While cementum shares many properties in common with bone and dentin, it is a unique mineralized tissue and acellular cementum is critical for attachment of the tooth to the surrounding periodontal ligament （PDL）. Resources for methodologies for hard tissues often overlook cementum and approaches that may be of value for studying this tissue. To address this issue, this report offers detailed methodology, as well as comparisons of several histological and immunohistochemical stains available for imaging the cementum-PDL complex by light microscopy. Notably, the infrequently used Alcian blue stain with nuclear fast red counterstain provided utility in imaging cementum in mouse, porcine and human teeth. While no truly unique extracellular matrix markers have been identified to differentiate cementum from the other hard tissues, immunohistochemistry for detection of bone sialoprotein （BSP）, osteopontin （OPN）, and dentin matrix protein 1 （DMP1） is a reliable approach for studying both acellular and cellular cementum and providing insight into developmental biology of these tissues. Histoloeical and immunohistochemical aooroaches Drovide insight on developmental biology of cementum.

Dynamic Analysis of the Expression of HSP70 during Experimental Tooth Movement in Rats

In this study, the expression of HSP70 during experimental tooth movement was dynamically observed and the relationship between HSP70 and orthodontic periodontal tissue remodeling were observed. The orthodontic appliance was placed between the right maxillary first molar and maxillary central incisors of adult SD rats to establish a rat molar movement model. Immunohistochemistry was performed 1, 3, 5, 7 and 14 day（s） after orthodontic force application to observe the expression and localization of inducible HSP70. The expression of HSP70 was strongly positive in the early stage of the tooth movement, became gradually less positive, and was weakly positive in the restoration stage. There was difference in staining pattern between different parts of PDL during the same period. These results suggest that the expression of HSP70 and difference in staining pattern among different parts of PDL during orthodontic tooth movement in rats may be implicated in stress response and remodeling of periodontal tissue.

Pilot study on binding of bovine salivary proteins to grit silicates and plant phytoliths

Mostly fed with grass in fresh or conserved form, cattle and other livestock have to cope with silicate defence bodies from plants （phytoliths） and environmental silicates （grit）, which abrade tooth enamel and could additionally interact with various salivary proteins. To detect potential candidates for silicate-binding proteins, bovine whole saliva was incubated with grass-derived phytoliths and silicates. Interactions of salivary proteins with pulverized bovine dental enamel and dentine were additionally analysed. After intense washing, the powder fractions were loaded onto 1D-polyacrylamide gels, most prominent adhesive protein bands were cut out and proteins were identified by mass spectrometry within three independent replicates. All materials were mainly botmd by bovine odorant-binding protein, bovine salivary protein 30× 10^3 and carbonic anhydrase VI. The phytolith/silicate fraction showed additional stronger interaction with haemoglobin β and lactoperoxidase. Conceivably, the binding of these proteins to the surfaces may contribute to biological processes occurring on them.

Pilot study on binding of bovine salivary proteins to grit silicates and plant phytoliths

Mostly fed with grass in fresh or conserved form,cattle and other livestock have to cope with silicate defence bodies from plants(phytoliths)and environmental silicates(grit),which abrade tooth enamel and could additionally interact with various salivary proteins.To detect potential candidates for silicate-binding proteins,bovine whole saliva was incubated with grass-derived phytoliths and silicates.Interactions of salivary proteins with pulverized bovine dental enamel and dentine were additionally analysed.After intense washing,the powder fractions were loaded onto 1D-polyacrylamide gels,most prominent adhesive protein bands were cut out and proteins were identified by mass spectrometry within three independent replicates.All materials were mainly bound by bovine odorant-binding protein,bovine salivary protein 30×10^(3) and carbonic anhydrase VI.The phytolith/silicate fraction showed additional stronger interaction with haemoglobinβand lactoperoxidase.Conceivably,the binding of these proteins to the surfaces may contribute to biological processes occurring on them.

合并惊厥发作的X连锁Charcot-Marie-Tooth病1型1例报告并文献复习

目的分析X连锁Charcot-Marie-Tooth病1型(CMT1X)的发病机制及出现惊厥的可能原因。方法回顾分析1例合并惊厥发作的CMT1X患儿的临床特征以及基因检测结果,并复习相关文献。结果男孩,7岁6个月,以可逆性脑白质病变为首发症状且出现惊厥;基因检测显示患儿缝隙连接蛋白Bl (GJB1)基因发生突变,C.425G>A(p.R142Q)。诊断为CMT1X。患儿与既往所报道病例的临床症状有差异。结论以惊厥为首发症状的CMT1X,系GJB1基因突变导致通道功能障碍所致,相同突变可出现不同临床表现。

Rapid genetic screening of Charcot-Marie-Tooth disease type 1A and hereditary neuropathy with liability to pressure palsies patients

We used the allele-specific PCR-double digestion method on peripheral myelin protein 22 （PMP22） to determine duplication and deletion mutations in the proband and family members of one family with Charcot-Marie-Tooth disease type 1 and one family with hereditary neuropathy with liability to pressure palsies. The proband and one subclinical family member from the Charcot-Marie-Tooth disease type 1 family had a PMP22 gene duplication; one patient from the hereditary neuropathy with liability to pressure palsies family had a PMP22 gene deletion. Electron microscopic analysis of ultrathin sections of the superficial peroneal nerve from the two probands demonstrated demyelination and myelin sheath hyperplasia, as well as an ＇onion-like＇ structure in the Charcot-Marie-Tooth disease type 1A patient. We observed an irregular thickened myelin sheath and ＇mouse-nibbled＇-Iike changes in the patient with hereditary neuropathy with liability to pressure palsies. In the Charcot-Marie-Tooth disease type 1A patient, nerve electrophysiological examination revealed moderate-to-severe reductions in the motor and sensory conduction velocities of the bilateral median nerve, ulnar nerve, tibial nerve, and sural nerve. Moreover, the compound muscle action potential amplitude was decreased. In the patient with hereditary neuropathy with liability to pressure palsies, the nerve conduction velocity of the bilateral tibial nerve and sural nerve was moderately reduced, and the nerve conduction velocity of the median nerve and ulnar nerve of both upper extremities was slightly reduced.

骨形态蛋白2调控牙囊成骨分化在牙齿萌出中作用的研究进展

牙囊作为牙齿萌出的必要器官,在诱导成骨/破骨细胞分化、促进萌出通道形成方面具有重要作用。骨形态蛋白2(BMP2)是一种多效形态因子,具有高度骨诱导活性,主要通过自分泌或旁分泌形式介导牙囊细胞向成骨细胞分化。近年来,关于BMP2通过调控牙囊成骨分化促进牙槽骨改建,保证牙齿萌出通道正常形成的相关研究日益引发众多学者的关注,然而具体机制尚不明了。本文通过对BMP2生物学性能及其与多种信号通路交互作用共同调节牙囊成骨分化的可能机制进行述评,旨在从骨代谢角度拓展牙齿萌出过程中分子调控机制的研究及牙齿萌出障碍的防治提供新的理论依据。

雷公藤甲素调控p38 MAPK/ERK/JNK信号通路对正畸牙移动模型大鼠牙周炎症及破骨细胞的影响

目的:探究雷公藤甲素通过调控p38丝裂原活化蛋白激酶(p38 mitogen-activated protein kinase, p38 MAPK)/细胞外信号调节激酶(extracellular signal-regulated kinase, ERK)/c-Jun氨基末端激酶(c-Jun amino-terminal kinase, JNK)信号通路对正畸牙移动模型大鼠牙周炎症及破骨细胞的影响。方法:构建正畸牙移动大鼠模型,成功建模48只随机分成模型组、雷公藤甲素低(50μg/kg)、高(100μg/kg)剂量组、雷公藤甲素高剂量(100μg/kg)+p38 MAPK激活剂(25μg)组,每组12只;另设对照组(12只健康大鼠)。各组给予相应方法干预2周。测量正畸牙移动距离;抗酒石酸酸性磷酸酶染色观察牙周组织破骨细胞并进行计数;免疫组织化学染色法检测牙周组织骨形态发生蛋白-2(bone morphogenetic protein-2,BMP-2)表达强度;酶联免疫吸附法检测肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)、白细胞介素-1β(interleukin-1β,IL-1β)、前列腺素E2(prostaglandin E2,PGE2)、骨保护素(osteoprotegerin, OPG)、核因子-κB受体活化因子配体(receptor activator of nuclear factor-κB ligand, RANKL)水平;蛋白印迹法检测牙周组织p38 MAPK/ERK/JNK通路相关蛋白表达。结果:与对照组相比,模型组正畸牙移动距离、牙周组织破骨细胞数目、BMP-2表达强度、血清TNF-α、IL-1β、PGE2、RANKL水平、磷酸化(phosphorylated, p)-p38 MAPK/p38 MAPK、p-ERK1/2/ERK1/2、p-JNK/JNK蛋白比值显著升高,血清OPG水平显著降低(P<0.05);与模型组相比,雷公藤甲素低、高剂量组正畸牙移动距离、牙周组织BMP-2表达强度、血清OPG水平依次升高,牙周组织破骨细胞数目、血清TNF-α、IL-1β、PGE2、RANKL水平、p-p38 MAPK/p38 MAPK、p-ERK1/2/ERK1/2、p-JNK/JNK蛋白比值依次降低(P<0.05);p38 MAPK激活剂可逆转高剂量雷公藤甲素对正畸牙移动模型大鼠的作用效果(P<0.05)。结论:雷公藤甲素可减轻正畸牙移动模型大鼠牙周炎症,降低破骨细胞数量,改善骨吸收,加速正畸牙移动,其机制与抑制p38 MAPK/ERK/JNK信号通路激活有关。

高氟低蛋白对放牧山羊牙基质发育的影响

对工业氟污染区枯草期发育的放牧山羊牙齿做了脱钙后的牙基质形态学观察。结果表明 ,健康牙齿镜下釉质与本质 ,牙骨质与牙本质界限清晰 ,牙骨质的厚度均匀一致 ,牙骨质与牙本质均致密 ,中毒组第 1切齿牙骨质与牙本质界限模糊 ,局部呈现明显疏松结构 ,釉质与本质界限不整齐 ,有的呈犬牙交错或破损 ;健康牙本质胶原排列整齐、致密、染色均匀 ,而中毒组第 1切齿本质胶原肿胀 ,弯曲 ,排列疏松 ,染色不均匀。结论 :高氟低蛋白对放牧山羊的牙基质有明显的病理影响 ,使基质结构发育不良 ,并进一步影响基质的钙化 ,从而使牙齿整体质量下降 。

釉蛋白在大鼠牙胚釉质发育中的表达特征

目的：观察釉蛋白（enamelin，En）在大鼠牙胚发育过程中的表达，探讨其可能的生物学功能。方法：采用免疫组织化学方法，检测出生后第1，3，7，10，14天SD大鼠第一磨牙牙胚中釉蛋白的表达特征。结果：大鼠出生后第1～14天釉蛋白在成釉细胞中的表达随细胞的分化、基质分泌而变化。釉蛋白在出生后第1天的成釉器前成釉细胞中表达为阴性，但在沿牙尖斜面的进入分泌期成釉细胞中表达阳性；在出生后3天的分泌期成釉细胞胞浆中表达阳性，在刚分泌形成的釉牙本质界呈强阳性表达；在出生后第7天的分泌期成釉细胞胞浆中表达阳性，在未矿化完全的釉质基质中为强阳性表达，且釉蛋白随矿化的程度不同而表达强弱不同；在出生后第10天的大鼠牙胚中釉蛋白仅在成熟期成釉细胞中有较弱的阳性表达，在矿化变薄的剩余釉质基质中仍有阳性表达；在出生后第14天的大鼠牙胚中，釉蛋白表达阴性。结论：釉蛋白由成釉细胞分泌，最初分布于釉牙本质界，位于发育中的釉质全层，随釉质成熟而逐渐减少，至釉质完全形成后而表达停止，提示釉蛋白在釉质形成中可能有重要作用。

氟对体外器官培养人牙胚骨形成蛋白表达的影响

目的 通过研究氟对牙胚发育早期骨形成蛋白 (BMP)表达的影响 ,初步探讨氟在早期牙胚发育中的可能作用机制。方法 4个月的人胚胎 ,取乳牙胚用RPMI16 4 0培养液进行器官培养 8d。免疫组化法研究 2 5mg·L-1和 5 0mg·L-1的氟对分泌前期牙胚的影响 ,观察培养第 2、4、6、8天时BMP表达的变化。采用图像分析仪对免疫组化染色结果进行灰度分析。结果 BMP的表达主要在造釉器。成釉细胞 ,中间层细胞和星网状层细胞均有BMP表达 ,牙乳头细胞或成牙本质细胞不表达BMP。 2 5mg·L-1氟时从培养第 6天开始BMP表达增强 ;5 0mg·L-1氟时从培养第 2天到第 6天BMP的表达增强 ,培养第 8天时BMP的表达降低。

L-Periaxin蛋白与Ezrin蛋白相互作用初步分析

Periaxin是施旺(Schwann)细胞中特异表达的支架蛋白之一,参与髓鞘成熟及稳定.Periaxin的基因缺失或突变导致脱髓鞘型腓骨肌萎缩症(CMT)4F亚型的发生.埃兹蛋白(ezrin)是一种膜骨架连接蛋白,其在维持细胞形态和运动方面具有重要作用,与肿瘤细胞转移密切相关.本文通过免疫共沉淀、双荧光共定位、YFP双分子荧光互补、GST-pull-down等实验方法,分析了L-periaxin蛋白与ezrin蛋白之间的相互作用.结果表明,L-periaxin蛋白与ezrin蛋白可在细胞质中共定位并可发生相互作用.

腓骨肌萎缩症1A型的临床、神经电生理和疾病基因突变分析

目的 观察腓骨肌萎缩症 (CMT) 1A型的临床、神经电生理特点和疾病基因的突变分析。方法对一CMT家系中 9个成员进行详尽的临床检查、疾病基因突变分析 ,对先证者进行神经电生理检查和神经肌肉活检。结果 本家系中 5人发病 ,符合常染色体显性遗传模式 ,除 1例患者无临床症状外 ,其余 4例均在2 0岁前起病。临床特点为进行性四肢远端肌无力、肌萎缩 ,末梢型感觉障碍 ,腱反射减弱或消失 ,足部畸形(高弓足 )。神经电生理检查示运动和感觉神经传导速度减慢。基因突变分析发现 17号染色体短臂 11 2区(17p11 2 )包含周围髓鞘蛋白 (PMP) 2 2基因的正向串联重复突变。结论 CMT1A型是CMT最常见类型 ,多于儿童期或青少年期起病 ,表现为进行性四肢远端肌无力、肌萎缩 ,腱反射减弱或消失。神经电生理特点为运动神经传导速度均一性减低 (<38m/s)。 17p 11 2区包含PMP 2 2基因在内的 1 5Mb(偶尔 <1 5Mb)的正向串联重复突变是CMT 1A最主要的突变型。

正常豚鼠牙齿和牙周组织中BMP的分布及其意义

目的：研究ＢＭＰ在牙齿生长发育和牙周组织改建中的作用；方法：利用牛骨形成蛋白单克隆抗体（ｂＢＭＰ－ＭｃＡｂ）免疫组织化学染色法，观察了正常豚鼠牙齿和牙周组织中ＢＭＰ的分布。结果：ＢＭＰ在豚鼠成熟的牙周组织中主要分布于靠近牙釉质和牙槽骨附近的成纤维细胞胞浆内；而在不断发育中的根尖部位ＢＭＰ染色更深；造釉细胞和成牙本质细胞染色呈强阳性；牙槽骨和已成熟的釉质、牙本质染色较浅。结论：ＢＭＰ与硬组织的形成和改建密切相关，牙周膜成纤维细胞与成牙本质细胞、成骨细胞一样具有成骨特性。

纤维粘连蛋白及骨形成蛋白-2、4在牙胚发育中的表达研究

目的观察纤维粘连蛋白(fibronectin,FN)和骨形成蛋白-2、4(BMP-2、4)在大鼠牙胚发育中的表达,探讨其在成牙本质细胞分化及成熟过程的时空表达关系,为明确牙齿发育的分子调控网络提供理论和实验基础。方法获取SD大鼠蕾状期和钟状期第一磨牙牙胚,通过免疫组化LsAB法观察FN和BMP-2、4的表达差异及相互关系。结果FN在蕾状期和钟状期都有表达,蕾状期主要分布在牙上皮、牙间质,周围非牙间质细胞为阴性,钟状期主要分布在成牙本质细胞分化活跃的区域和分化中的内釉上皮细胞。钟状期BMP-2、4的表达较强,主要分布在成牙本质细胞分化活跃的区域。结论BMP-2、4和FN在牙齿发育的蕾状期和钟状期均有表达,但表达的阳性分布区不同。