利塞膦酸钠对骨质疏松大鼠牙槽骨Bcl-2、BAX表达的影响

目的: 观察利塞膦酸钠对骨质疏松大鼠下颌牙槽骨显微结构、抗凋亡因子Bcl-2、凋亡因子BAX表达以及骨细胞凋亡的影响。方法: 30只6月龄雌性SD大鼠,随机分为3 组（每组10只）,即Sham组（假手术组）、OVX组（接受双侧卵巢切除术）和RIS组（接受双侧卵巢切除术,然后给予利塞膦酸钠）;造模3个月后,取各组大鼠下颌骨进行micro-CT扫描,并通过TUNEL染色以及Bcl-2、BAX免疫组织化学染色检测下颌骨骨细胞的凋亡。采用SPSS 13.0软件包对组间数据进行比较。结果: 与Sham组相比,OVX组牙槽骨丧失和骨细胞凋亡明显增多;RIS组与OVX组相比,骨细胞凋亡显著减少,BV/TV显著增加,Bcl-2 表达增加,Bcl-2/BAX比值增加（P<0.05）。结论: 利塞磷酸钠增加下颌牙槽骨中Bcl-2的表达和Bcl-2/BAX的比值,部分逆转去卵巢骨质疏松大鼠的牙槽骨丧失,减少下颌骨骨细胞凋亡。     

局部激活破骨细胞对大鼠应用双膦酸盐后拔牙创愈合的影响

目的:通过动物模型,研究局部激活破骨细胞对应用双膦酸盐后拔牙创愈合的影响,以期找到预防双膦酸盐相关性颌骨坏死的方法。方法:选用24只8周龄雌性SD大鼠随机分为实验组和对照组,行双侧卵巢切除术(ovariectomy,OVX),术后3个月开始应用双膦酸盐。用药一个月后,拔除大鼠左侧上颌第一磨牙。实验组拔牙创内放置含有巨噬细胞集落刺激因子(macrophage-colony stimulating factor, M-CSF)与核因子-κB受体活化因子配体(the receptor activator of nuclear factor-κB ligand, Rankl)的明胶海绵,对照组放置含有生理盐水的明胶海绵。拔牙后2周,收取样本,评价拔牙创愈合情况。结果:TRAP染色结果显示实验组牙槽窝内的破骨细胞数量较对照组明显增多。免疫组织化学染色结果显示实验组成骨能力标记物骨桥蛋白(osteopontin,OPN)、牙本质基质蛋白1(dentin matrix protein 1,DMP1)表达量增加。组织学检测结果显示实验组拔牙创牙槽窝新生骨质较对照组明显增多。结论:局部激活破骨细胞可以促进应用双膦酸盐后的拔牙创愈合。     

Nestin阳性细胞过表达DMP1对小鼠颌骨密度的影响

目的探讨Nestin阳性细胞中牙本质基质蛋白1(DMP1)的作用。方法 DMP1是牙齿和骨中重要的矿化蛋白,但是Nestin阳性细胞中DMP1的作用仍不清楚。我们构建了Nestin阳性细胞中过表达DMP1的转基因小鼠。以野生型(wild type,WT)小鼠为对照组,通过HE染色,Micro CT检测DMP1-Tg小鼠颌骨的变化,进一步通过TRAP染色检测DMP1-Tg小鼠颌骨破骨方面的变化。结果相对于WT小鼠,DMP1-Tg小鼠颌骨骨量下降;TRAP染色显示DMP1-Tg小鼠下颌骨破骨细胞增多。结论在下颌骨发育过程中,Nestin阳性细胞中过表达DMP1对骨形成发挥抑制作用。     

基于RANKL-RANK-OPG轴研究丹参素防治牙槽骨骨质疏松的作用

目的:探讨RANKL-RANK-OPG轴在丹参素防治牙槽骨骨质疏松中的作用。方法:SD大鼠随机分为3组:对照组、去卵巢组和丹参素治疗组。实验90 d后取大鼠牙槽骨,HE染色观察牙槽骨组织形态学改变,组织化学染色方法检测牙槽骨组织中TRAP的活性,免疫组化的方法检测牙槽骨组织中RANKL和OPG的表达情况。结果:与去卵巢组相比:丹参素治疗组牙槽骨骨量明显增多,TRAP阳性的破骨细胞数减少,RANKL/OPG减小。结论:丹参素防治牙槽骨骨质疏松可能与其调控RANKL-RANK-OPG轴有关。     

骨折愈合中牙本质基质蛋白1与破骨细胞表达时间效应的观察

目的探讨骨折愈合过程中牙本质基质蛋白1（dentin matrix protein 1，DMP1）与破骨细胞的时间效应。为研究DMP1在体内矿化重建中的作用提供参考。方法将40只成年Wistar雄性大鼠左侧下颌支骨折，建立下颌骨骨折模型。骨折后5、7、14、21d处死大鼠，取骨痂和对侧正常骨组织（对照组），分别采用HE染色、TRAP染色和免疫组织化学链霉抗生物素．蛋白过氧化物酶（streptavidin perosidase，sp）法染色切片检测。结果在对照组正常下颌支组织中没有DMP1的表达，偶见破骨细胞；实验组在骨折后14～21d是破骨细胞活动高峰。结论DMP1与破骨细胞在骨折愈合过程中具有一定的时间效应。     

不同去势时间对大鼠牙槽骨微结构影响的比较研究

目的 比较不同去势时间对大鼠牙槽骨微结构的影响,探讨牙槽骨骨质疏松大鼠模型建立成功的参数。方法 24只6月龄雌性SD大鼠,随机分为4组：（1）对照组1（Sham1）;（2）去势组1（OVX1）;（3）对照组2（Sham2）;（4）去势组2（OVX2）。分别在全麻下行假手术和双侧卵巢去势术。于术后3个月和4个月处死各组大鼠,取双侧上颌骨标本,通过Micro-CT扫描、HE染色、抗酒石酸酸性磷酸酶（TRAP）染色、Van Gieson染色、荧光双标观察并分析牙槽骨微结构的变化。结果 去势3个月后OVX1组与Sham1组大鼠相比,体重增加25.09%（P<0.01）;牙槽骨骨体积分数（BV/TV）、骨小梁数目（Tb.N）、骨小梁分离度（Tb.Sp）,牙骨质界-牙槽嵴顶（CEJ-ABC）距离无改变（P>0.05）,骨小梁宽度（Tb.Th）降低了12.44%（P<0.05）,破骨细胞数量增加了40.12%（P<0.01）;骨形成沉积率（MAR）无明显改变（P>0.05）;去势4个月后OVX1组与Sham1组大鼠相比,体重进一步增加了26.25%（P<0.01）,BV/TV、Tb.Th、MAR分别降低了11.15%、17.22%和38.45%（P<0.01）,Tb.Sp和破骨细胞数量分别增加了81.89%和35.67%（P<0.01）,Tb.N和CEJ-ABC距离无变化（P>0.05）,HE和Van Gieson染色均表明OVX2组大鼠牙槽骨骨量降低,骨髓腔面积增加,骨小梁微结构破坏、变细,部分区域发生断裂。结论 6月龄雌性SD大鼠去势4个月后,牙槽骨发生明显骨质疏松,可作为合适的牙槽骨骨质疏松大鼠模型参数的理论依据。     

咬合创伤对OVX小鼠牙周组织中HMGB1表达的影响

目的:研究咬合创伤对OVX(ovariectomized,切除卵巢的)小鼠牙周组织中高迁移率族蛋白B1(HMGB1)表达的影响。方法:取24只7周龄雌性昆明小鼠,随机分为4组,每组6只:①对照组(CON);②咬合创伤组(OT);③OVX组(OVX);④OVX+咬合创伤组(OVX+OT)。OVX组和OVX+OT组小鼠均在实验开始时进行双侧卵巢摘除术,手术7周后对OT组和OVX+OT组小鼠建立咬合创伤模型,对照组不做任何处理,所有小鼠均于实验第8周处死取材,制作石蜡切片进行HMGB1表达量的免疫组织化学检测,并运用软件将结果数值化。结果:HE染色结果显示接受咬合创伤模型的小鼠牙周膜纤维出现排列紊乱、断裂,抗酒石酸酸性磷酸酶(TRAP)染色显示OVX+OT组破骨细胞表达量明显高于其他组别,HMGB1在OVX+OT组中表达量最高,OT组和OVX组的破骨细胞和HMGB1的表达量略高于CON组,OT组和OVX组两组之间无显著差。结论:HMGB1在OVX小鼠受到咬合创伤时的牙周组织改建中发挥重要作用。     

破骨细胞在大鼠正畸牙移动性根吸收修复早期中的改变

目的初步研究大鼠正畸牙移动性根吸收修复早期中破骨细胞和骨保护因子(osteoprotegerin,OPG)的变化和规律,探讨破骨细胞在正畸导致的炎性牙根吸收修复中的作用。方法建立大鼠正畸牙移动性根吸收修复早期模型,免疫组化检测OPG的表达,TRAP染色观察破骨细胞的变化。结果实验第1天,OPG表达量下降,第3天以后逐渐恢复至生理水平。实验第1天起,TRAP染色阳性细胞逐渐减少,实验第7、10、14天,TRAP染色阳性数量已逐渐恢复至生理水平。结论施力终止后,大鼠牙根即停止吸收,并于1~3d后开始牙根修复,OPG的量与此过程密切相关。     

唑来膦酸对小鼠下颌拔牙创早期修复过程的影响

目的: 通过构建小鼠双膦酸盐颌骨坏死（bisphosphonate-related osteonecrosis of the jaw, BRONJ）模型,探讨该类药物对拔牙创早期缺损修复过程的影响。方法: 18只8~9周龄C57BL/6雄性小鼠,随机分为空白对照组及唑来磷酸给药组,通过腹腔注射+左下颌第一磨牙拔除诱导其产生双膦酸盐颌骨坏死样病变。随后选取术后3、5、7天3个时间点,H-E染色观察其大体愈合情况,Trap染色观察破骨细胞分布及数量,免疫组织化学染色观察早期成骨向转录因子及破骨特异性蛋白的表达差异。实验重复3次,采用ImageJ软件对图像进行分析和数据转换,采用SPSS 20.0软件包进行显著性分析。结果: 与对照组相比,唑来膦酸给药组拔牙创早期缺损修复过程延迟。术后3天成骨转录因子RUNX2表达降低,术后7天破骨细胞特异性蛋白CTSK数量减少;术后早期TRAP表达降低,骨改建行为整体受到抑制。结论: 唑来膦酸可在术后3天抑制成纤维细胞长入拔牙窝,并使RUNX2表达含量降低,抑制新骨形成。其还能使拔牙术后3、5、7天破骨细胞表达TRAP含量减少及在术后7天降低CTSK表达量,抑制破骨细胞行使骨吸收功能。     

Effects of ovariectomy on trabecular structures of rat alveolar bone

An association between postmenopausal osteoporosis and tooth loss has been proposed. However, histomorphometrical changes in alveolar bone following estrogen deficiency are rarely reported with data on microtrabecular structural changes. To clarify the relationship between estrogen deficiency and tooth loss, we histomorphometrically analyzed the trabecular structural changes of mandibular alveolar bone in ovariectomized rats. Twenty-four adult female Fischer rats were used. Eight rats were sacrificed on day 0 (baseline). The remaining 16 rats were divided into two groups. One group was ovariectomized bilaterally (OVX) and the other group was subjected to sham surgery (Sham). After administration of tetracycline and calcein, the animals were sacrificed 60 days after surgery. Bone histomorphometry, node-strut analysis and measurement of thickness of alveolar bone proper were performed on the interradicular septum of the first molar on the sagittal surface. The trabecular bone volume and trabecular number of the OVX group were significantly lower than those of the baseline and Sham groups. All of the bone resorptive and formative parameters of the OVX group were significantly higher (about one-and-a-half times) than those of the Sham group. Several osteoclasts were seen lining the irregular, eroded surface facing the bone marrow in the OVX group. Furthermore, the OVX group tended to have low microtrabecular stiffness and showed significantly thinner distal alveolar bone proper than in the baseline and Sham groups. In summary, estrogen deficiency caused osteoporotic changes and thin alveolar bone proper in the interradicular septum of rat first molar. This phenomenon might accelerate destruction of alveolar bone and tooth loss, especially in elderly women affected by periodontal disease.     

雌激素缺乏对大鼠根尖周炎病变区TLR4表达的影响

目的:探究雌激素缺乏对大鼠根尖周炎病变区TLR4表达的影响。方法:30只大鼠随机分为两组:OVX组、SHAM组,暴露下颌第一磨牙髓腔,分别于开髓后 0、7、14、21 d处死大鼠。HE染色、酶组织化学染色、免疫组织化学法观测根尖周组织骨吸收范围,破骨细胞数及TLR4的表达。结果:与SHAM组相比,OVX组根尖周炎病变区骨吸收范围增大、破骨细胞数升高、TLR4的表达增强。结论:雌激素缺乏可增强大鼠根尖周炎病变区TLR4的表达。     

Initial changes in alveolar bone volume for sham-operated and ovariectomized rats in ligature-induced experimental periodontitis

Objectives

Osteoporosis is a disease characterized by a reduction in bone mass, poor bone strength, and microarchitectural deterioration primarily in postmenopausal women. With respect to periodontal disease, osteoporosis is thought to contribute to pre-existing alveolar degeneration although the association between both diseases is not fully characterized. The aim of the present study was to observe the initial changes in mandibular alveolar bone for sham-operated and ovariectomized (OVX) rats in ligature-induced experimental periodontitis.

Materials and methods

A total of 64 Wistar rats (7 weeks of age, 180–200 g) were used in this study (32 control sham-operated animals?+?ligature placement, 32 OVX animals?+?ligature placement). Following an 8-week period to induce an OVX model, micro-CT analysis was performed to calculate vertical and furcation bone loss of mandibular first molars at time points 0, 3, 7, and 11 days following ligature placement (six animals per group per time point). Furthermore, histological analysis was performed to calculate the loss of alveolar bone crest height from the cemento-enamel junction, and tartrate-resistant acid phosphatase (TRAP) staining was utilized to calculate the number of osteoclasts.

Results

The results from the present study demonstrate that OVX animals showed significant vertical bone loss at all time points when compared to control sham-operated animals. In the furcation area, no significant difference in bone loss was observed between sham-operated and OVX animals at 0, 3, and 7 days; however by 11 days, a significant decrease in bone volume/total volume and trabecular thickness was observed in the OVX group. The histological analysis also revealed that alveolar bone crest height was significantly reduced in OVX animals, and TRAP staining further revealed the greater number of multinucleated osteoclasts peaking at 3 days postligature placement.

Conclusion

The results from the present study demonstrate a direct correlation between the osteoporotic phenotype and the progression of periodontal breakdown in a diseased-induced animal model.

Clinical relevance

It may be suggested that an osteoporotic phenotype has the potential to speed periodontal breakdown and thus contributes to the overall degeneration of the periodontium in patients suffering from postmenopausal bone loss. Future research from human clinical studies are necessary to further understand the relationship between periodontal disease and osteoporosis.

     

Heterogeneity of osteoclast activity and bone turnover in different skeletal sites

ObjectiveTo compare osteoclasts and bone turnover in the cranial and appendicular skeletons of mice and determine whether estrogen depletion has an impact on these differences.DesignIn vitro osteoclastogenesis (OCG) was performed on osteoclasts precursors derived from calvarial, mandibular and femoral bone marrow. In vitro, mature osteoclasts were stained with TRAP in plastic petri dishes and with DAPI and Phalloidin on glass coverslips to identify mature osteoclasts and compare osteoclast surface area and nuclei number in the different bone sites, respectively. Quantification of osteoclast resorption pit (Rpit) volume and surface area from different bone sites was achieved using dentin slices stained with Picrosirius red and confocal microscopy. In vivo TRAP, static and dynamic histomorphometric analyses were performed on 5-month-old mouse calvarial, long bone and mandibular trabecular bone to compare bone resorption and formation rates, respectively. Mice were ovariectomized (OVX) at 5 months of age and sacrificed at 6 months of age to establish an osteoporosis model for differences in osteoclasts activity and to monitor the changes in bone turnover rates in the three bone sites upon estrogen depletion.Results Phalloidin stained calvarial osteoclasts were larger compared to long bone and mandibular osteoclasts. Rpits from osteoclasts derived from mandibular bone were smaller and had lower volume values compared to long bone and calvarial bone Rpits. In vivo analysis showed significant increases in bone formation rates in calvarial trabecular bone compared to long bone and mandibular trabecular bone. Turnover was enhanced upon estrogen depletion in calvarial trabecular bone. Resorption was increased without a corresponding increase in bone formation in the trabecular metaphysis of long bone. Mandibular trabecular bones do not appear to be affected by OVX.ConclusionThe cranial and appendicular skeletons differ from one another in that osteoclasts from calvarial bone have the highest resorptive capacity which is coupled to bone formation both pre and post-OVX. Mandibular bones show the lowest turnover rates and are not affected by OVX.     

软食对青春期大鼠下颌后牙区牙槽骨微结构的影响

目的 :观察软食喂养引起的机械负荷改变对青春发育期大鼠下颌后牙区牙槽骨微结构的影响。方法 :取16 d龄雄性SD大鼠20只,随机分为软食组(SD组)和硬食组(HD组),每组各10只。7周后,运用显微CT(Micro CT)技术观察分析2组大鼠下颌第一磨牙(M1)区牙槽骨的松质骨微结构,苏木精-伊红染色对脱钙后的下颌骨M1区域进行组织学观察。结果:Micro-CT结果显示,较HD组而言,SD组M1区松质骨的骨小梁厚度(Tb.Th)显著减少(P<0.01),骨小梁间距(Tb.Sp)显著升高(P<0.05);组织学结果显示,SD组M1牙槽纵隔以及根尖区域骨小梁较HD组稀疏、变细,骨髓腔增大,近牙周韧带区域骨细胞分布减少。结论:软食喂养引起的负荷降低减少了下颌后牙的牙槽骨骨小梁的厚度、增加了骨小梁间距,从而影响了其骨微结构。     

牙槽骨缺损修复后正畸牙齿移动时机探讨

目的    探讨牙槽骨缺损修复后不同时机进行牙齿移动的时机。方法    本研究于2013年9月至2014年3月在福建医科大学实验动物中心和福建医科大学口腔医学院完成。选择40只大白兔,建立一侧下颌牙槽骨缺损模型,植入骨粉,置Bio-Gide膜,另一侧正常拔牙对照。分别于术后1周和1、2、3个月牵引两侧下颌第二磨牙近中。加力1个月后,取实验侧和对照侧下颌骨组织块,电子游标卡尺测量下颌第二磨牙与第三磨牙之间的距离;组织块制作石蜡切片,进行常规苏木精-伊红染色,选取第二磨牙牙根根中1/3处牙周膜,每个部位随机选择3个视野计数破骨细胞数目总和。1周组、1个月组、2个月组、3个月组的实验侧与对照侧的下颌第二磨牙移动距离、同一时间点压力区的破骨细胞数均行配对t检验分析。结果    1周组、1个月组实验侧下颌第二磨牙移动距离小于对照侧,压力区破骨细胞少于对照侧,差异均有统计学意义（均P＜0.05）;而2个月组、3个月组差异均无统计学意义（均P＞0.05）。结论    牙槽骨缺损修复2个月后适合进行正畸牙移动。     

���۹�ȱ���޸������������ƶ�ʱ��̽��

??Objective    To investigate the effect of tooth movement at different time after the repair of alveolar bone defects. Methods    Defective alveolar bone model was established on one side in forty white rabbits??which were filled with bone meal and attached with Bio-Gide membrane as experiment sides. The other side was performed routine tooth extraction as control. Track the mandibular second molar in both sides respectively in 1 week??1 month??2 months and 3 months after operation. One month later??the distance between the mandibular second molar and third molar was measured with electronic vernier caliper in the experiment side and control side. The mandibular tissue was made paraffin section and hematoxylin eosin staining. Three views of the periodontal ligament in a third place of the mesial roots of the second molar was randomly chosen to count the total number of osteoclasts. Paired-t test analysis was made to evaluate the displacement of the mandibular second molar in experiment and control side??and to evaluate the number of osteoclasts in two side. Results    In Group 1w and Group 1 m??the displacement of the mandibular second molar in experiment group was smaller than that in the control side??P??0.05??. There was no statistical significance in Group 2 m and Group 3 m. The number of osteoclasts in the experiment side was less than the control group in Group 1 w and Group1 m??P??0.05??. No statistical significance in Group 2 m and Group 3 m was found. Conclusion    Orthodontic treatment can be performed two months after the repair of alveolar bone defects.