Forward deviation of the mandibular condyle enhances endochondral ossification of condylar cartilage indicated by increased expression of type X collagen

OBJECTIVE: Using type X collagen as a marker, this research was designed to examine the alteration of condylar growth in response to mandibular condylar forward positioning. METHODS: One hundred female Sprague-Dawley rats with 5 weeks of age were randomly divided into five experimental and five control groups. In the experimental groups, bite jumping appliances created forward positioning of the condyle. The experimental rats, together with the age-matched controls, were sacrificed on days 3, 7, 14, 21 and 30, respectively. Tissue sections were cut in the sagittal plane through the mandibular condyle and were processed for in situ hybridization and immunostaining of type X collagen and then for quantitative imaging analyses. RESULTS: (1) Both type X collagen mRNA in situ hybridization signals and type X collagen immunostaining were localized within the hypertrophic zone of the condylar cartilage. (2) With condylar forward positioning, the level of type X collagen mRNA signals (8,541 +/- 74 microm(2) at peak) was 300% higher than that in the controls (2,117 +/- 78 microm(2) at peak); type X collagen immunostaining in condylar advancing groups (54,864 +/- 134 microm(2) at peak) was 254% more than that in the controls (15,470 +/- 121 microm(2) at peak). (3) The amount of type X collagen mRNA signals and immunostaining in experimental and control groups reached the highest levels at day 14 and day 21, respectively, indicating that an increase in endochondral ossification occurred 21 days after condylar forward deviation. CONCLUSION: Condylar forward repositioning provokes an enhanced maturation of condylar chondrocytes resulting in increased synthesis of type X collagen, a extracellular protein that attributes to endochondral ossification.     

软骨内成骨修复骨损伤的调节机制

软骨内成骨是主要的骨修复方式之一,它遵循特定的生物学步骤,并涉及复杂的调节机制。近年来,基于软骨内成骨模型开展的骨再生研究日益增多,全面了解其发生机制可以为骨再生的研究提供重要依据。因此,本文对近期软骨内成骨修复骨损伤的调节机制做一综述。     

甲状旁腺相关蛋白在鼠胚髁突外植体软骨内成骨中的作用

目的探讨甲状旁腺相关蛋白(PTHrP)对体外培养的鼠胚髁突软骨内成骨的影响。方法体外解剖分离鼠胚髁突,行外植体培养,通过组织学、免疫组化等方法观察PTHrP对体外培养的髁突外植体软骨内成骨的影响。结果髁突外植体在无血清半固态培养系统中能正常发育。加入人PTHrP(1-34)后,实验组髁突长度的增加较对照组明显,两组间差异有显著性(P<0.05);组织学及免疫组化染色显示:加入人PTHrP(1-34)后培养的髁突外植体增殖层和肥大软骨细胞层明显增厚,同时Ⅱ及Ⅹ型胶原在增殖层和肥大软骨细胞层中表达增强。结论PTHrP可刺激髁突外植体软骨增殖层和肥大层软骨细胞的增殖,促进髁突软骨内成骨的形成。?     

下颌前伸对成年大鼠髁突软骨Ⅹ型胶原表达的影响

目的:建立年轻成年大鼠下颌前伸动物模型,以X型胶原为检测指标,观察髁突软骨内成骨及其与下颌前伸持续时间的关系.方法: 9 周龄雌性大鼠75 只,分为3 组,其中2 组为实验组,另一组为对照组,实验组动物戴用统一规格自制的咬合前导矫治器,分别戴用12 h和24 h.3 组动物分别在实验后3、7、14、21、30 d处死后取双侧髁突组织,使用免疫组化和原位杂交方法从蛋白水平和基因水平检测髁突软骨组织切片中X型胶原的表达情况.结果:免疫组化结果显示, 24 h实验组X型胶原表达量在21 d时最高,且高于其他实验组;而12 h实验组峰值出现在30 d.原位杂交结果与免疫组化结果基本吻合.结论:功能矫治下颌前伸均能诱导年轻成年大鼠髁突软骨发生改建,但与12 h间歇性加力方式相比,24 h持续加力方式作用效果明显,且见效快.     

CCN2在软骨内成骨过程中作用的研究进展

<正>在软骨内成骨过程中,由骨髓间充质干细胞分化而来的软骨细胞首先形成生长板软骨,随着软骨中血管的产生,软骨逐渐被骨组织所替代。躯干骨和四肢骨以及骨折后的骨痂主要是通过软骨内成骨完成生长发育和修复,此过程受到许多生长因子以及激素的影响,包括印第安刺猬蛋白(Indian hedgehog,Ihh)、甲状旁腺激素相关蛋白(parahthyroid hormone-related protein,PTHrP)、骨形态发生蛋     

渐进性咬合紊乱对髁突软骨I型胶原表达的影响

目的:研究渐进性咬合紊乱对髁突软骨I型胶原表达变化的影响和意义。方法:用兔子口内造成渐进性咬合紊乱动物模型,用定量免疫组化染色法观察髁突软骨I型胶原的表达变化。结果:与对照组相比,实验组纤维层和增殖层表达增强,肥大层出现异常表达。在实验期内,实验组髁突大多数部位,纤维层和肥大层的表达有降低趋势,增殖层则持续增强。结论:渐进性咬合紊乱可以导致兔髁突软骨退行性变,髁突纤维层和增殖层软骨细胞I型胶原高表达,肥大层异常表达,软骨趋于纤维化或骨化。     

Ihh-PTHrP负反馈信号通路对髁突软骨内成骨作用的研究现状

临床研究发现,颌面部发育畸形的患者,尤其是Ⅱ类错患者,常同时伴有颞下颌关节盘前移位,而青少年期颞下颌关节盘前移位与颌面部发育畸形存在密切关系。其原因可能与关节盘移位导致髁突表面的应力分布发生改变有关,但具体机制尚不明确。印度豪猪蛋白(Ihh)-甲状旁腺相关蛋白(PTHrP)信号通路是调节骨骺生长板软骨细胞增殖、分化、肥大和矿化的重要负反馈轴,在软骨内成骨中发挥着关键的作用。同时,Ihh是机械应力信号向生物信号转导的重要媒介,介导机械应力信号向刺激软骨生长的生物信号转化。本文对Ihh-PTHrP负反馈信号通路对下颌骨髁突软骨内成骨作用的研究现状作一综述。     

经Ⅱ型胶原修饰的快速成形聚酯材料对软骨细胞黏附和增殖的影响

目的：探讨经Ⅱ型胶原修饰的快速成型丙交酯一乙交酯共聚物（poly—lactic—co—glycolic acid，PLGA）（50：50）对兔软骨细胞黏附和增殖的影响，及其作为组织工程软骨支架的可行性。方法：快速成型方法制作三维多孔PLGA支架材料，Ⅱ型胶原进行表面修饰，通过水解实验测定材料的吸水率。取消化后第二代软骨细胞与三维支架复合培养3、7和14d后，消化、收集细胞，细胞计数方法测定细胞的增殖，扫描电镜观察细胞的增殖、黏附情况。另取部分样本继续培养28d，行组织学观察。结果：Ⅱ型胶原表面修饰过的快速成型PLGA支架有较高的亲水性，从而提高了软骨细胞黏附和增殖效果，促进了细胞外基质的形成。组织切片可见孔内有大量软骨细胞和细胞外基质，可见典型软骨陷窝样结构。结论：Ⅱ型胶原表面修饰的PLGA有适宜的吸水性，与软骨细胞有较好的黏附性和生物相容性，是较理想的组织工程生物材料。     

氟对体外培养人牙乳头细胞分泌I型胶原的影响

目的　了解氟对体外培养人牙乳头细胞分泌I型胶原的影响。方法　对人牙乳头细胞体外培养 ,分别给予 0 .0 g/L、0 .2× 10 -6g/L、1.0× 10 6g/L、5 .0× 10 6g/L、2 5 .0× 10 -6g/L氟处理 ,采用Westernblot方法分析氟对细胞培养外I型胶原的影响。结果　体外培养的人牙乳头细胞合成Ⅰ型胶原可以分泌Ⅰ型胶原。 0 .0g/L、0 .2× 10 -6g/L、1.0× 10 6g/L、5 .0× 10 6g/L氟对细胞外Ⅰ型胶原量无显著差异 (P >0 .0 5 ) ;2 5 .0× 10 -6g/L氟处理组细胞外I型胶原量较其它组高 (P <0 .0 5 )。结论　过量氟可能抑制细胞外I型胶原降解     

Immunohistochemical identification of type I and type III collagen and chondroitin sulphate in human pre-dentine: a correlative FEI-SEM/TEM study

AIM: To identify type I- (I-CF) and type III-collagen fibrils (III-CF) and chondroitin 4/6 sulphate (CS) within human pre-dentine by means of a correlative analysis under field emission in-lens-scanning electron microscopy (FEI-SEM) and transmission electron microscopy (TEM). METHODOLOGY: Human-extracted teeth were obtained and submitted to either a pre-embedding or a post-embedding immunolabelling procedure using monoclonal primary antibodies anti-I-CF, anti-III-CF and anti-CS. Gold-conjugated secondary antibodies were coupled to primary antibodies to visualize labelling under the electron beam. Correlative labelling patterns were obtained for I-CF and CS under both FEI-SEM and TEM. RESULTS: Field emission in lens-SEM analysis revealed an intricate three-dimensional network of I-CF and CS clarifying the intimate relationship between the two main components of the pre-dentine organic matrix. TEM analysis revealed odontoblasts exhibiting intracellular labelling for CS, which became more intense and diffuse over the pre-dentine organic matrix. The same diffuse immunoreaction was revealed for I-CF, whereas a weak immunolocalization of III-CF was found scattered throughout the pre-dentine layer and over the collagen fibrils. CONCLUSIONS: Both the pre- and post-embedding immunohistochemical approaches have led to the visualization of CF- and CS-labelling distribution within the pre-dentine layer, adding further knowledge on the elucidation of collagen-proteoglycans interaction in the organic matrix of human dental roots.     

The effect on osteogenesis of type I collagen applied to experimental bone defects

Abstract –  The purpose of the present investigation was to evaluate the effects of type I collagen sponge on the healing of bone defects. In this study, six adult male rabbits were used. After the induction of general anesthesia with intraperitoneal kethamine, the anterior surfaces of tibias of the rabbits were surgically exposed, and two holes with 4 mm in diameter were prepared on each tibia for the investigation. Only one hole in each tibia was filled with type I collagen, the other unfilled hole was used as control. During the study, radiopacity changes in the radiographs of the tibias of the rabbits were evaluated. The animals were killed on the 28th day, and histologic sections of the tibias were prepared. On the 28th day, it was histopathologically observed that collagen cavities were filled with new bone. In addition, it was determined that there was an increase in radiopacity of the defect areas from 14 to 28 days in both groups, and there were statistically a significant difference between control and collagen groups ( P  = 0.0001). In this study, consequently, it was determined that type I collagen sponge in the experimental cavities provides a more rapid regeneration of bone defects compared with non-filled cavities.     

生长期兔颞下颌关节盘前移位后髁突软骨胶原表达的变化

目的:建立生长期兔颞下颌关节不可复性关节盘前移位动物模型,检测髁突软骨内Ⅱ型胶原和X型胶原的表达,探讨青少年颞下颌关节盘不可复性前移位与髁突软骨内成骨的关系,及其与下颌骨发育不对称畸形之间存在相关性的机制.方法:取生长期新西兰大白兔40只,右侧颞下颌关节手术建立不可复性关节盘前移位模型,左侧行假手术作为对照.实验动物于建模后24 h、1、4、8、12周分组处死取材.通过免疫组织化学方法检测髁突软骨组织内Ⅱ型胶原和X型胶原在蛋白水平的表达,采用PASW statistics 18.0软件包对每组样本实验侧和对照侧进行配对t检验.结果:Ⅱ型胶原在盘移位后24h、1、4、8周时与对照侧均无显著差异,12周时较对照侧表达升高(P＜0.05).X型胶原在盘移位后24 h(P＜0.01)、1周(P＜0.01)、4周(P＜0.05)时较对照侧显著降低,8周、12周时实验侧与对照侧间无显著差异.结论:不可复性关节盘前移位对兔髁突软骨内成骨过程造成干扰,这种影响可能是单侧颞下颌关节盘前移位后患侧下颌支高度不足和下颌骨不对称畸形的重要原因.     

年轻恒牙牙根发育过程中牙髓中Ⅲ型胶原的表达

目的：研究牙根发育不同阶段的人年轻恒牙牙髓中Ⅲ型胶原的表达变化：方法：根据牙根的发育情况，分为牙根刚开始发育、牙根发育中和根尖闭合共3组：采用SP免疫组化法。对各组牙髓标本的石蜡切片进行Ⅲ型胶原的免疫组化染色：结果：图像分析显示、3个组的冠髓中心染色强度之间有非常显著性差异，以牙根刚开始发育时染色最强，根尖闭合时染色最弱：在牙根刚开始发育组、牙髓中心区染色强于牙髓外层。结论：随着年轻恒牙牙根的逐渐发育，Ⅲ型胶原在牙髓中的表达逐渐减弱，因而可能参与牙根的发育。     

The effect of saliva or serum on bacterial and Candida albicans colonization on type I collagen

Colonization of Candida albicans on oral surfaces can serve as a reservoir for disseminated infections, such as aspiration pneumonia and gastrointestinal infection, particularly in the immunocompromised host. Therefore, the aim of this study was to investigate the effects of salivary and serum pellicles on C. albicans, Streptococcus mutans, S. sanguis, Lactobacillus and Actinomyces colonization on type I collagen, a major organic component of periodontal ligaments. The colonization potential of two isolates each of C. albicans, S. mutans and S. sanguis, and a single isolate each of Lactobacillus and Actinomyces to uncoated (control), saliva-coated or serum-coated type I collagen plates (surface area 143 mm(2), Cell Disk; Sumitomo, Tokyo, Japan) was examined using a bioluminescent adenosine triphosphate assay based on firefly luciferase-luciferin system. The results revealed that with mutans streptococci, a saliva pellicle was significantly more effective in promoting bacterial colonization compared with the pellicle-free collagen disc, and the serum-coated sample significantly inhibited the colonization of streptococci (anova; P < 0b01). In contrast, in the case of C. albicans, Lactobacillus and Actinomyces isolates, a serum pellicle was significantly more effective in promoting the colonization, followed by saliva pellicle and uncoated specimen (anova; P < 0b01). These results suggested that crevicular fluid rich in seruminous components would promote the colonization of Candida, Lactobacillus and Actinomyces on type I collagen as opposed to streptococci which showed greater avidity to saliva-coated collagen.     

Histopathological changes in collagen and matrix metalloproteinase levels in articular condyle of experimental model rats with jaw deformity

OBJECTIVE: To investigate the dynamics of the cartilage matrix in the articular condyle after removal of a side shift plate; Emergence of type I, II, and III collagen in the matrix as well as changes in levels of matrix metalloproteinase (MMP)-1, -8, and -13 that degrade collagen were studied histopathologically and immunohistochemically. DESIGN: Lateral displacement of the mandible was achieved by attaching a side shift plate to the anterior teeth of the maxilla in male rats at 6 weeks. The wearing period of the side shift plate was 8 weeks. Observations were made at 0, 1, 2, 4 and 8 weeks after removal. RESULTS: In histopathological findings, the timing of proliferation of the layer of hypertrophy varied between the bilateral sides. In immunohistochemical findings a significant decline in the expression of type II collagen in the displacement side was observed immediately after removal. Moreover, the expressions of MMPs were elevated in both sides on 0 weeks. At 1 week after removal, a significant elevated in the expression of type II collagen, MMPs was decline in both sides. CONCLUSIONS: After removal, the levels of MMP-1, -8, and 13 were reduced and the emergence of type II collagen increased. Thus, cellular outgrowth was initiated to trigger intracartilaginous ossification to restore the cartilage matrix.     

Distribution and synthesis of type VII collagen in oral squamous cell carcinoma

The distribution of the basement membrane anchoring fibril component type VII collagen was studied in oral squamous cell carcinoma by using in situ hybridization and immunohistochemical methods. The expression of type VII collagen in oral normal mucosa, lichen planus and epithelial dysplasias was also investigated. In squamous cell carcinomas, the signals for type VII collagen raRNA were Socated exclusively in malignant peripheral cells in tumour islands and in fibro-blast-like cells among the stromal tissue. In normal buccal mucosa, type VII collagen mRNA expression was located in basal epithelial cells. In oral lichen planus and epithelial dysplasias, the signals for type VII collagen mRNA were also located in basal keratinocytes: however, the signal was especially strong in some epithelial cells. In oral squamous cell carcinomas, the linear immunohistochemical staining pattern of type VII collagen was noted surrounding partly squamous epithelial tumour cell islands, and a large number of tumour cells showed a cytoplasmic staining reaction using the type VII collagen antibody. Some fibroblast-like stromal cells also showed a positive immunostaining reaction. In conclusion, the results of this study indicate that a high synthesis level, but an impaired distribution of type VII collagen, are highly characteristic of squamous epithelial tumour cells.     

口腔癌相关成纤维细胞对Ⅰ型胶原蛋白降解作用的研究

目的：对比研究口腔癌相关成纤维细胞（CAFs）和正常成纤维细胞（NFs）对Ⅰ型胶原蛋白的降解能力。方法将Ⅰ型胶原蛋白凝胶与CAFs和NFs共同培养24h、48h、72h后,收集上清液,按照羟脯氨酸检测试剂盒说明测定羟脯氨酸含量。结果：CAFs上清超滤液中羟脯氨酸含量均值高于同时间段NFs组均值,并且作用24h、48h时两组降解作用均随时间的延长而增加。结论：CAFs降解Ⅰ型胶原蛋白降的能力强于NFs,提示CAFs与口腔鳞癌基质降解及肿瘤转移有关。