局部注射川芎嗪对大鼠牙移动保持阶段骨保护素的表达

BACKGROUND: Ligustrazine has been shown to restore the function of the femoral head via the revascularization, increased blood flow, the absorption of necrotic bone, and bone regeneration. OBJECTIVE:To study the effects of ligustrazine on remodeling of periodontal tissues and the expression of osteoprotegerin in the maintenance phase in rats with orthodontic tooth movement. METHODS: Thirty-two healthy male Wistar rats were included and equally randomized into four groups. Maxillary left first molar mesialization was performed through traction of 50 g force for 21 days to establish the rat model of tooth movement. 5, 10, 15 mg/L ligustrazine (50 µL) were locally injected into the first molar periosteum in model rats on the day before removing the orthodontic forcing device. Same volume of saline was injected in the control group. The injection was administered every other day. At 1 and 4 weeks after injection, the distance of tooth movement, the recurrence distances and percentage were determined and calculated. The pathological changes in periodontal tissues were observed by immunohistochemistry and hematoxylin-eosin staining. The width of the parodontium and number of osteoblasts were observed under an optical microscope. RESULTS AND CONCLUSION: The recurrence distance in the control group was increased compared with the experimental group, while the number of osteoblasts and osteoprotegerin immunoreactivity were decreased. Good width of the parodontium and small recurrence trend were found in 10 mg/L ligustrazine group. These findings indicate that ligustrazine promotes the proliferation of osteoblasts and enhances the expression of osteoprotegerin, which is beneficial to the retention of teeth after orthodontic surgery. 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     

慢性氟中毒SD大鼠正畸牙移动的位移及速率变化

背景：临床报道氟牙症患者正畸疗程比非氟斑牙的时间要长,但其牙移动速度减慢主要体现在牙移动周期的哪些环节还不清楚。目的：研究一个牙移动周期内染氟大鼠正畸牙移动的位移、速率变化规律,为以后的相关机制研究及氟牙症患者的正畸治疗提供实验依据。方法：3周龄SD大鼠12只随机分为染氟组和对照组,每组6只,雌雄各半,150 mg/L氟化钠水溶液每日喂养染氟组大鼠复制氟中毒模型,然后两组大鼠装配镍钛拉簧正畸加力装置,以70 g力值近中移动双侧第一磨牙,在第0,3,7,14,21,28天使用高精数显游标卡尺(最小精度0.01 mm)测量上颌第一磨牙近中面龈缘中点至同侧上颌中切牙远中-舌-龈角的间距,观察第一磨牙近中移动的位移和速率变化。结果与结论：①染氟组大鼠出现Ⅱ-Ⅲ级氟牙症,尿氟高于正常水平(P < 0.05),表明慢性氟中毒模型复制成功;②两组大鼠牙移动的总位移及总速率无明显性别差异;③染氟组牙移动的总位移及总速率有低于对照组的趋势,但观察期内尚无统计学差异;④随时间延长,两组大鼠牙移动的分段位移和分段速率呈现先增加后降低然后回升的趋势,且染氟组回升更明显;⑤结果表明,从全周期时间维度上看,慢性氟中毒大鼠牙移动受到一定程度抑制,总位移及总速率均减小,且无明显性别差异;慢性氟中毒大鼠正畸牙移动符合典型的牙移动周期特征,即“快速-迟缓-回升”3个阶段,迟缓期缩短,提示可能有破坏性改建。https://orcid.org/0000-0002-2160-7763 (丁雪) 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     

大鼠正畸牙移动中Toll样受体4在牙周组织中的表达

背景：学者们对正畸力作用下牙周组织的改建做了大量的研究,但对于在大鼠牙齿移动过程中Toll样受体4在牙周组织中表达的研究尚未涉及。 目的：研究在正畸牙移动过程中,大鼠牙周组织中Toll样受体4的表达。 方法：采用NiTi拉簧建立大鼠正畸牙移动模型,力值50 g。分别于加力后1,3,5,7,10,14 d取正畸牙周组织,检测Toll样受体4的表达。 结果与结论：免疫荧光染色显示,正畸加力1 d,牙周组织中Toll样受体4的表达量增强,至加力后5 d时表达量最大,之后逐渐降低,第14天时回落至初始水平。可见正畸力可以刺激牙周组织中Toll样受体4的表达,Toll样受体4可能参与了牙周组织的改建。     

正畸牙移动过程中牙周组织白细胞介素8的表达

背景：白细胞介素8作为一种与骨改建相关的炎性细胞因子,参与牙周组织的改建,促进牙槽骨的吸收,是骨吸收的标志物之一。 目的：观察正畸力对牙周组织改建过程中白细胞介素8表达的影响。 方法：将10周龄雄性SD大鼠上颌一侧第一磨牙与上颌切牙之间安置正畸装置,并施加0.49 N近中向正畸力,在加力后1,3,5,7,14 d取材,进行组织形态分析法、免疫组化染色检测白细胞介素8在牙周组织中表达的阳性细胞的面密度值。 结果与结论：正常大鼠牙周组织内白细胞介素8的表达呈弱阳性;随加力时间的延长大鼠牙周组织牙周膜细胞白细胞介素8表达增强,加力后5 d达到高峰,之后开始下降。实验提示正畸力可引起局部牙周组织炎症及白细胞介素8的释放。正畸牙移动早期,白细胞介素8的释放可能是牙周组织早期炎症反应和牙槽骨改建的触发因素之一。     

动静组合载荷加速正畸牙移动的动力学分析

目的 分析机械振动加速正畸牙移动中颌骨及牙周组织的应力分布,探讨动静组合载荷加速正畸牙移动的机理.方法 采用Mimics、SolidWorks、Geomagic和ANSYS Workbench软件建立包括牙齿、牙周膜、牙槽骨松质骨、牙槽骨皮质骨的有限元模型,施加侧向静态正畸力、低值高频机械振动载荷,进行动力学分析.结果 牙槽骨及牙周组织的近远向正应力(Y向应力)分布可清晰区分张力、压力区,呈现周期性变化,并且其频率与加载的低值高频机械振动载荷一致;牙槽骨及牙周组织vonMises应力亦呈现周期性变化,但无法区分张力、压力区.结论 在口腔正畸领域,近远向正应力为合适的力学激励表征量;侧向静态正畸力与低值高频机械振动载荷组合的动静组合载荷是一个可行的加速正畸牙移动方法.研究结果可为低值高频机械振动加速正畸移动提供指导.     

正畸牙移动细胞生物力学研究进展

近年来,正畸牙移动细胞生物力学领域的研究蓬勃发展。牙周膜在正畸牙移动中的核心地位被广泛认识和接受。以牙周膜细胞为核心,包括骨髓基质干细胞、成骨细胞、成牙骨质细胞、成肌细胞等的体外研究成为揭示正畸牙移动生物学机制的重要手段。体外研究模型从通过基底形变、重物、液压、离心等方式对二维培养细胞进行应力加载的传统方式,发展到建立各种对细胞进行三维培养和应力加载的新型模型。骨改建循环中以成骨分化和破骨生成诱导为主的相关分子表达成为研究的热点。此外,牙周膜干细胞的细胞力学研究也是极具前景的崭新方向。     

青少年女性月经周期不同阶段加力对正畸牙移动的影响

背景：雌激素对正畸牙齿移动有影响,目前仅有动物实验证明,雌激素水平越低,正畸牙移动量越大,雌激素水平越高,正畸牙移动量越小。 目的：分析青少年女性正畸患者月经周期的不同时期加力对正畸牙移动的影响。 方法：选取12例14-18岁已具有月经初潮,月经规律,需要拔除上颌第1前磨牙的女性患者。采取自身对照,将患者上颌左右两侧尖牙,随机分为月经期加力组和排卵期加力组,应用种植体支抗加力远中移动尖牙,月经期加力组加力2周后排卵期加力组开始加力。各组分别于加力即刻及4周时取模,灌制超硬石膏模型,测量各组尖牙向远中移动的距离,采用GraphPad Prism5软件包对数据进行统计学分析。 结果与结论：月经期加力组尖牙移动量大于排卵期加力组(P < 0.05)。提示青少年女性正畸患者在月经期加力正畸牙的移动速度较排卵期正畸牙的移动速度显著增加,可有效缩短正畸矫治疗程。 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：     

12～14岁正畸患者骨龄与牙移动速率关系的探讨

目的 探讨正畸治疗中骨龄与牙移动速率的关系。方法 选择23例需上、下颌双侧第一双尖牙减数矫治的女性患者，年龄12～14岁，平均13．4岁，治疗前均摄左手腕掌指骨片，利用骨成熟度指数计测法测量骨龄。用150g相对恒定力移动同一牙弓内的尖牙，比较尖牙远移速率。结果 使用相对恒定力向远中牵移尖牙，尖牙移动的速率存在明显的个体差异。年龄与牙移动速率之间无线性相关关系；而骨龄与牙移动速率间具有线性关系，随骨龄的上升，牙移动速率减慢。结论 在相同的正畸力作用下，牙移动速率因人而异，骨龄是影响牙齿移动速率的一个重要因素。     

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.     

不同牙槽骨高度下正畸牙移动的三维有限元分析

目的 探讨不同牙槽骨高度下正畸牙移动的生物力学特点,为正畸临床治疗提供理论参考。方法 建立牙槽骨高度正常以及降低1/3、1/2、2/3的4组下颌牙列模型。模拟下颌中切牙在不同载荷下进行舌向移动、远中移动、压低移动。分析牙齿牙周膜应力及位移的分布和变化。结果 在3种移动中,随着牙槽骨高度的降低和矫治力的增大,牙颈部应力集中程度和牙周膜等效应力增加。同时,各观察点位移量和冠根位移差增大,牙齿倾斜移动趋势加重。当牙槽骨高度降低2/3,舌向及远中移动矫治力达150 g,压低移动达100 g时,牙周膜等效应力增大至最大,牙齿倾斜移动趋势最明显。结论 牙槽骨高度的降低会加重牙槽嵴顶的应力集中及牙齿倾斜移动的趋势。对于牙周条件差的正畸患者,应根据其牙槽骨高度相应降低矫治力,确保正畸治疗的安全有效。     

正畸加力后大鼠牙周组织中BMP的分布变化及其意义

本研究首次应用抗牛骨形成蛋白单克隆抗体（ｂＢＭＰ－ＭｃＡｂ）免疫组织化学染色法，观察加力后的大鼠上第一磨牙牙周组织中ＢＭＰ的分布，并与正常不加力组相比较。结果显示：ＢＭＰ在正常牙周组织中主要分布于牙周韧带中，尤其是牙槽骨和牙骨质表面，并与不同部位的骨改建活动相一致；正时加力后，张力区成骨活跃，ＢＭＰ染色较深（强阳性），压力区染色为阴性，只有活跃的破骨细胞染色较深；已接近成熟的新生牙槽骨及牙骨质则染色较弱。结果表明；ＢＭＰ可以作为骨改建活动的标志之一，在正畸骨改建中起着十分重要的作用。     

Effect of hypoxia on the expression of RANKL/OPG in human periodontal ligament cells in vitro

To investigate the impact of hypoxia on the expression of receptor activator of NF-kB ligand (RANKL) and osteoprotegerin (OPG) in human periodontal ligament cells (hPDLCs) in vitro. hPDLCs were incubated in a hypoxic atmosphere of 2% O₂, 5% CO₂, 94% N₂ at 37°C for 6, 12, 24 and 48 h. After that, cell proliferation assay was determined using CCK-8 technique. SP immunocytochemistry method was performed to trace the expression of hypoxia-inducible factor 1 alpha (HIF-1α) in hPDLCs. The expression levels of RANKL and OPG were investigated using real-time PCR and ELISA. As a control, the cells were incubated at normoxic conditions of 20% O₂, 5% CO₂, 75% N₂. All results were analyzed using one-way ANOVA at a significant level of P=0.05. OPG mRNA and protein levels were down-regulated meanwhile RANKL mRNA and soluble RANKL (sRANKL) protein levels were up-regulated after stimulated by hypoxia. The relative RANKL/OPG expression ratios were increased in both mRNA and protein levels. The expression of RANKL mRNA and sRANKL protein levels was enhanced significantly (P<0.05) under the hypoxia conditions at 12 h, 24 h and 48 h while OPG mRNA and protein were reduced significantly (P<0.05) at 12 h, 24 h and 48 h. Hypoxia can affect the expression of RANKL and OPG in hPDLCs, which constitute an important pathogenic event in the alveolar bone resorption. Lack of oxygen in periodontal tissue may accelerate the development of periodontitis.     

OPG／RANKL在大鼠骨关节炎模型中的表达及意义

目的：检测骨保护素（OPG）和核因子Kβ受体活化因子配体（RANKL）在大鼠骨关节炎（OA）模型软骨下骨中的表达,探讨其与OA软骨下骨病变的关系及意义。方法：36只大鼠分两组。模型组行右膝前交叉韧带＋内侧副韧带横断术造模,对照组仅切开关节囊。术后2,6,8周取两组膝关节标本,观察外观、Mankin评分和骨形态计量参数变化,并检测软骨下骨中OPG和RANKL含量及其比值。结果：模型组软骨Mankin评分随时间逐渐增加（P〈0．01）;骨形态计量学显示造模后2周骨量降低,6、8周增加（P〈0．05）;模型组OPG含量由低变高,RANKL含量则由高变低,其比值逐渐增加（P〈0．01）。结论：OPG、RANKL在OA软骨下骨异常重建中起着重要作用。由此推测,在OA早期对其调控可能抑制异常骨重建,将是治疗OA的一种潜在有效方法。     

实验性根尖周炎模型大鼠核因子?B的表达

BACKGROUND:mRNA expression level of nuclear factor-kappa B (NF-?B) in periapical periodontitis has been shown to be significantly higher than that in normal periapical tissue. OBJECTIVE:To observe the expression of NF-?B in rats with periapical periodontitis. METHODS:Twenty male Sprague-Dawley rats aged 6 weeks were enrolled to establish apical periodontitis model at the right mandibular first motar (experimental group), and the left mandibular first motar as normal control group. Five rats were randomly selected at postoperative 1, 2, 3, and 4 weeks to make frozen sections of the mandibular tissue. The morphology of the periapical tissue was observed through hematoxylin-eosin staining, and the expression level and distribution of NF-?B were detected by immunohistochemical staining. RESULTS AND CONCLUSION: (1) Hematoxylin-eosin staining showed that the apical periodontal tissue of the mandibular first molar at the right side had local inflammatory response and spread to peripheral tissues; while there was no pathological changes in the control group. (2) Immunohistochemistry results revealed that NF-?B expression increased from the 1st week to 2nd week after surgery, and then went down at the 3rd week and reached the lowest point at the 4th week; moreover, the expression level at each time exhibited significant differences (P < 0.05). The amount of NF-?B-positive cells in the experimental group was significantly higher than that in the control group (P < 0.05). (3) These findings suggest that the expression level of NF-?B holds close correlation with the process of periapical periodontitis indicating that NF-?B may participate in the inflammatory reaction of periapical periodontitis.  中国组织工程研究杂志出版内容重点：肾移植;肝移植;移植;心脏移植;组织移植;皮肤移植;皮瓣移植;血管移植;器官移植;组织工程     

Effects of RANKL on the thymic medulla

The thymic medulla provides a microenvironment where medullary thymic epithelial cells (mTECs) contribute to the establishment of self-tolerance by the deletion of self-reactive T cells and the generation of regulatory T cells. The progression of thymocyte development critically regulates the optimum formation of the thymic medulla, as discussed in this article. Of note, it was recently identified that RANKL produced by positively selected thymocytes plays a major role in the thymocyte-mediated medulla formation. Indeed, transgenic expression of soluble RANKL increased the number of mTECs and enlarged the thymic medulla in mice. The effects of RANKL on the thymic medulla may be useful for the engineering of self-tolerance in T cells.     

Histological Evaluation of Periodontal Ligament in Response to Orthodontic Mechanical Stress in Mice

The purpose of the study was to determine the cell dynamics in periodontal ligament in response to mechanical stress during orthodontic movement. Following Waldo''s method, a square sheet of rubber dam was inserted in between the first and second maxillary molars in 10 ddY mice leaving the stress load for 3 hours. After 3 days and at 1 week, cell count on pressure and tension sides of the periodontal ligament was determined. Furthermore, the type of cell present after mechanical stress was identified using GFP bone marrow transplantation mouse model. Immunohistochemistry was carried out at 0 min (immediately after mechanical stress), 24 hours, 1 week, 2 weeks and 6 months. Temporal changes in the expression of GFP-positive bone marrow derived cells were examined. Moreover, double immunofluorescent staining was performed to determine the type of cell in the periodontal ligament. Cell count on the tension side tremendously increased 3 days after mechanical stress. At 1 week, spindle and round cell count increased compared to the control group. These changes were observed on both tension and pressure sides. Cell count on pressure side at 3 days (22.11+/-13.98) and at 1 week (33.23+/-11.39) was higher compared to the control group (15.26+/-8.29). On the tension side, there was a significantly increased at 3 days (35.46+/-11.85), but decreased at 1 week (29.23+/-13.89) although it is still higher compared to the control group (AD+/-SD: 10.37+/-8.69). Using GFP bone marrow transplantation mouse model, GFP positive cell count increased gradually over time in 6 months. GFP positive cells were also positive to CD31, CD68 and Runx2 suggesting that fibroblasts differentiated into osteoclasts and tissue macrophages. In conclusion, mechanical stress during orthodontic movement promoted the increase in the number of cells in the periodontal ligament on both tension and pressure sides. The increase in the number of cells in the periodontal ligament is believed to be due to the migration and cell division of undifferentiated mesenchymal cells.     

Immunolocalization of lubricin in the rat periodontal ligament during experimental tooth movement

Lubricin is a protein which contributes to the boundary lubrication, facilitating low friction levels at the interfacing surfaces of joints. In tendons and ligaments it facilitates the relative movement of collagen bundles. Its expression is affected by mechanical signals and cytokines. During application of orthodontic forces to teeth, there is a transduction of mechanical forces to the cells of the periodontal ligament (PDL), which triggers several biological reactions causing the synthesis of prostaglandins, cytokines and growth factors. The aim of the present study was to examine the immunolocalization of lubricin and to evaluate if it is time-dependently and differentially detected within the PDL following the application of orthodontic forces to create areas of compression and tension. This was achieved by placing elastic bands between the maxillary first and second molars of 16 male Sprague-Dawley rats (each weighing 120-200 g) for 12 and 24 h. The molar-bearing segments were dissected and processed for histological and immunohistochemical examination. Binding of a monoclonal antibody was used to evaluate lubricin localization using an indirect streptavidin/biotin immunperoxidase technique. Lubricin, was constitutively expressed in the PDL of rat molars. After the experimental force was applied to the tooth, lubricin was down-regulated, on both sides (compression and tension) of the PDL, in a time-dependent fashion, although to a different extent, being at any time more expressed on the tension side. Furthermore, in every sample, almost all PDL cells in the adjacent tooth cementum and alveolar bone, were more heavily immunolabeled by lubricin antibody, contrary to those located in the central portion of the PDL. Lubricin expression therefore seems related to PDL remodeling and tooth displacement following the application of an orthodontic force, and it appears that lubricin may play an important role during tooth movement.     

川芎嗪对类风湿性关节炎外周血RANK／RANKL／骨保护素途径干预作用的研究

目的观察川芎嗪对类风湿性关节炎（RA）模型大鼠RANK／RANKL／0PG在外周血中CD3^＋T淋巴细胞、中性粒细胞、CD14单核细胞的表达率及平均荧光强度,探讨川芎嗪在RA骨破坏和炎症过程巾的意义。方法大鼠随机分成5组,正常对照组、模型对照组、川芎嗪大剂量组、川芎嗪小剂量组、阳性药物对照组,每组10只。给药7d后,应用间接免疫荧光标记和流式细胞技术对各组大鼠外周血相关指标进行检测分析。结果与正常对照组相比,RA大鼠骨保护素（OPG）表达明显降低,从正常的24．7降至18．7（q=4．2,P〈0．05）,RANK、RANKL变化不明显,经过川芎嗪治疗后,大剂量组OPG有明显的回升,至23．8％（q=3．97,P〈0．05）,小剂量组变化不明显。RANK在CD3^＋细胞、中性粒细胞、CD14单核细胞上的平均荧光强度明显降低,分别为20．6、135．4、84．2,经川芎嗪大剂量治疗后明显升高,分别达到31．0、192．1、95．6（q=10．4、q=8．6、q=6．3,P〈0．05）。结论大剂量川芎嗪可以通过调节OPG／RANK／RANKL途径对RA起一定的作用。