下颌骨牵引成骨过程中血运重建方式初步探讨

目的通过建立兔下颌骨牵引成骨实验动物模型,观察其动态过程,初步探讨血运重建方式及机制。方法选用新西兰白兔30只,6只动物做空白对照组;24只动物行右侧下颌骨植入外置式颌骨牵引器。经7d延迟期后,按1mm/d速率延长下颌骨7d,然后固定8周。在延迟期第7天,牵引期第2、4、7天,固定期第1、3、6、8周时分别处死3只动物,用X线片、苏木精-伊红染色、免疫组化方法检测血管和新骨生成情况,以及微血管密度变化规律。结果实验组22只兔成功进行下颌骨牵引延长,牵引区血管生成方式以芽生和血管上皮岛为主。在牵引期第2天,骨断端微血管密度为28.2±7.0,明显高于其他各组(P<0.01),在固定期下降明显,固定第8周时,微血管密度为4.3±1.3,与正常组无显著性差异(P>0.05)。结论在牵引初期牵引骨断端有强烈的微血管反应,血运重建先于新骨重建;固定期微血管密度降低,血管成熟,血运重建随新骨生成改建完成而结束。     

血管内皮细胞生长因子、胰岛素样生长因子-1在下颌骨牵张成骨与骨缺损中的表达和意义

目的研究血管内皮细胞生长因子(VEGF)和胰岛素样生长因子(IGF)-1在牵张成骨和骨缺损修复中的表达和意义。方法28只犬随机分为牵引组和直接延长组各12只及正常对照组4只,在牵张第6天,固定2周、固定8周时两组分别处死4只动物,取牵张区新骨组织用免疫组化染色方法观察比较VEGF、IGF-1的表达。结果下颌骨牵张组和直接延长组VEGF、IGF-1均呈高水平表达,牵张6 d和牵张2周时,牵张组VEGF的表达较直接延长组增高(P<0.05),而IGF-1的表达则在牵张固定2周时牵张组较直接延长组增高(P<0.05),两者随着固定时间的延长,表达逐渐下降。结论VEGF、IGF-1可能共同参与促进下颌骨牵张成骨新骨的形成。     

下颌骨牵张成骨过程中TGF-β1动态表达的实验研究

目的:观察转化生长因子-β1(TGF-β1)在牵张成骨过程中时间和空间上的表达,探讨TGF-β1发挥的作用及其作用机制。方法:选用成年新西兰大白兔16只,行两侧下颌骨切开术,经7天间歇期后以0.5mm/12h的速度牵张,7d后固定。分别于间歇期1d、7d,牵张期1d、4d、7d,固定期1、3、5周随机处死2只动物取下颌骨标本,运用SABC免疫组织化学染色方法,对不同时间段的下颌骨标本进行TGF-β1的检测。结果:TGF-β1在潜伏期和固定期表达较弱,牵张期表达明显增强,在牵张第7天表达达高峰,且集中表达于未分化间充质细胞、成纤维细胞、成软骨细胞和成骨细胞。结论:TGF-β1在牵张成骨过程中,发挥着较为重要的作用。有望利用外源性TGF-β1提高牵张成骨形成骨的质和量,从而为牵张成骨术更好地应用于临床提供理论基础。     

下颌骨骨折愈合过程中血管内皮生长因子及其受体的表达

目的研究血管内皮生长因子(VEGF)及其受体Flt1在下颌骨骨折愈合中的表达规律。方法采用新西兰大耳白兔25只,随机分为术后48h和1、3、5、8周5个时相组,每组5只,以健侧为对照,制作左侧下颌骨体部骨折模型,利用原位杂交、免疫组织化学方法检测VEGF及其受体Flt1在骨折端的表达情况。结果在伤后48h~8周VEGF mRNA及VEGF在骨折部位被多种细胞表达,其表达强度随时间变化而变化,以1~3周为表达的高峰期。在伤后48h~8周的骨折端不同细胞内检测到VEGF的受体Flt1,1~3周为表达高峰期。结论VEGF及其Flt1受体表达贯穿于骨折愈合的始终,VEGF可能在骨折愈合过程中起重要作用。     

兔下颌牵张后血管内皮生长因子在新骨组织中的定位表达

目的 研究血管内皮生长因子（VEGF)在兔下颌牵张成骨过程中的定位表达。方法 对12只大耳白兔行双侧下颌骨牵张成骨术，在牵张结束后当天及7、14和28d分别处死3只动物，取牵张区骨痂。采用组织学和免疫组化方法观察微血管生成和VEGF的表达变化。结果 下颌骨延长后牵张间隙内有强烈的血管生成反应及高水平的VEGF，表达。VEGF阳性信号主要定位于血管内皮细胞和增殖活跃的成骨细胞。结论 牵张力刺激可以导致牵张间隙中强烈的血管生成反应，VEGF可能在牵张后骨再生的血管生成和新骨形成过程中起非常重要的调控作用。     

机械张应力对兔腭中缝血管内皮生长因子mRNA表达的影响

目的　观察在快速扩张兔腭中缝的扩张期和固定期血管内皮因子 (VEGF)mRNA表达情况。方法　用螺旋分裂基托扩大矫治器 (Haas矫正器 )扩张兔上牙弓 ,每 12h 0 .2 5mm ,共扩张牵引 14d ,分别于即刻 ,第 1、2、3、4、6周取材 ,标本常规进行逆转录聚合酶链反应 (RT -PCR)检测VEGFmRNA的表达。结果　第 1、2、3、4、6周VEGFmRNA表达量实验组均高于对照组。在实验组VEGFmRNA各组间的变化趋势为随着机械应力快速扩张 ,VEGFmRNA的表达量逐渐上升 ,固定 1周达峰值 ,以后逐渐下降 ,到固定 4周表达水平接近正常。结论　机械牵张力刺激可以导致内源性VEGF生成 ,VEGF可能在缝牵引成骨过程中血管生成及随后的新骨生成过程中扮演重要的角色     

山羊双侧下颌骨牵引成骨动物模型的建立

目的:建立一个可行性良好的山羊下颌骨牵引成骨模型。方法:将6只山羊的下颌骨截断,安置牵引器,延迟期4 d后以0.5 mm/次,2次/d的速度牵引10 d;随后进入固定期。分别于固定期的2、4、6、8周处死动物,进行大体标本和放射学观察。结果:牵引过程被所有山羊耐受,牵引长度达到预期效果。结论:山羊是一种良好的牵引成骨动物模型;该模型有助于DO临床的应用及研究。     

兔下颌骨牵张成骨中VEGF与NOS的相关性研究

目的:研究VEGF、iNOS和eNOS在兔下颌骨牵张成骨中的表达及其相关关系;探讨NOS和VEGF的相互作用及在促进新骨生成中的作用机制。方法:日本大耳白兔20只,随机分为五组,每组4只。分别处死空白对照组、牵张后1天组、1周组、2周组、4周组动物,取牵张处骨组织做成切片,行X线和组织学观察。结果:X线下示4周后牵张处骨缺损消失,组织学示牵张处骨小梁逐渐成熟;VEGF与NOS在形成新骨中均有高水平表达,VEGF同iNOS成正相关,r=0.844,P<0.01;VEGF同eNOS成正相关,r=0.647,P<0.;01;结论:VEGF、NOS可能共同参与促进牵张成骨新骨的形成,二者可能在上诉过程相互作用,促使成骨。     

文摘

45.延迟期对兔下颌骨牵张成骨术的影响眼英演/AidaT…∥IntJOralMaxillofacSurg.-2003熏32穴1雪.-54-62近年来牵张成骨术(distractionosteogenesis熏DO)已广泛用于颅面骨的延长,下颌骨牵张成骨术的延迟期为0～14d。本研究通过观察兔下颌骨牵张成骨术初期不同延迟期的组织学改变,探讨下颌骨牵张成骨术的最佳延迟期。材料和方法16只日本成年白兔,重3.0～3.5kg,全麻下在下颌第一前磨牙前行双侧下颌骨皮质下截骨术,放置口外固定牵张器,按延迟期0d、2d、5d、和10d将动物分成4组,牵引速度0.25mm/12h,牵引10d处死所有动物,测量牵张间隙长度。一…     

腺病毒介导的人骨形成蛋白2基因转染促进下颌牵张成骨的实验研究

目的探讨局部应用腺病毒介导的入骨形成蛋白2（adenovirus vectors containing human bone morphogenetic proteins 2, Ad-hBMP-2）对兔下颌骨牵张成骨的影响。方法24只新西兰大白兔随机分为实验组（12只）和对照组（12只），并建立下颌骨双侧牵张成骨模型。经过5d潜伏期后，以0．5mm／12h的速度牵张7d。固定期第1天，在实验组骨牵张区注射0．2ml滴度为10^12pfu／L的Ad-hBMP2，对照组骨牵张区注射0．2ml滴度为10^12pfu／L的腺病毒介导的增强型绿色荧光蛋白。在固定期第7、14、28天对下颌骨牵张区进行骨密度及新生骨量比较。结果Ad-hBMP-2治疗组牵张区骨密度及新生骨量明显高于对照组。结论腺病毒介导的人骨形成蛋白2具有促进兔下颌牵张成骨的作用。     

Expression of vascular endothelial growth factor and its receptors after mandibular distraction osteogenesis

During distraction osteogenesis, angiogenic activity is essential for new bone formation. This study examined the expression of vascular endothelial growth factor (VEGF) and two of its receptors, Flt-1 (VEGFR-1) and Flk-1 (VEGFR-2), in cellular components after mandibular distraction osteogenesis. Unilateral mandibular distraction (0.5 mm twice per day for 10 days) was performed in six mongrel dogs. Two animals each were killed on days 7, 14 and 28 after completion of distraction. The distracted mandibular segments and contralateral undistracted control segments were harvested and processed for immunohistochemical examination. Seven days after distraction, there was a significant increase in the expression levels of VEGF and its receptors in the osteoblasts, osteocytes and immature fibroblast-like cells compared to control specimens. These levels were maintained for 14 days after distraction in the osteoblasts and fibroblast-like cells. Twenty-eight days after distraction, VEGF and VEGFR-1 were expressed only moderately/weakly in the osteoblasts, and no VEGFR-2 expression was detected in the cellular component of the distracted bone. Throughout the observation period, VEGFR-1 expression was stronger than that of VEGFR-2. The expression patterns of VEGF and its receptors suggest that it plays an important role in osteogenesis, and that osteoblasts and immature fibroblast-like cells of the distracted bone may have an autocrine growth effect during distraction osteogenesis.     

Expression of bone morphogenetic proteins during mandibular distraction osteogenesis in rabbits.

PURPOSE: We examined the expression pattern of bone morphogenetic proteins (BMPs) during mandibular distraction osteogenesis in rabbits and also investigated the mechanism of membranous bone distraction. MATERIALS AND METHODS: Twenty-three rabbits underwent mandibular distraction (protocol; no latency period, a 1-week distraction at 0.5 mm/d, and a 2-week consolidation period). Samples were collected at 3, 5, and 7 days of distraction and at 1-week and 2-week consolidation. We prepared undecalcified fresh-frozen sections and immunohistochemically evaluated the expression of BMPs 2 through 8. RESULTS: Both endochondral ossification and intramembranous ossification were observed. The expression of BMPs 2, 4, 5, and 6 was observed continuously from the beginning of distraction. BMP-7 was expressed weakly. The expression of BMP-3 was not observed conspicuously during distraction but was strongly expressed at 1- and 2-week consolidation. CONCLUSION: The expression pattern of BMPs during membranous bone distraction was similar to that during long bone distraction, but it differed from the expression pattern of long bone distraction in that the expression of BMPs was maintained for 2 weeks after the completion of distraction.     

牵张成骨修复兔下颌骨缺损中血管生成素-1的表达及意义

目的探讨血管生成素(Ang)-1在牵张成骨修复兔下颌骨缺损中的时空表达及生物学意义。方法对24只大白兔行单侧下颌骨缺损牵张成骨术,分别在延迟期末、牵张中期、牵张期末、固定期第12、、35、、7周末各处死3只动物,取牵张区骨痂,采用组织学和免疫组化法观察微血管生成以及Ang-1的表达变化。结果下颌骨牵张区主要以膜内成骨方式成骨,在牵张区内有明显的血管生成及较明显的Ang-1的表达。在新生血管管周前成骨细胞和成骨细胞中可见Ang-1的表达。非应力区(缺损区)以软骨内成骨为主,在肥大的软骨细胞中存在Ang-1弱表达。结论牵张力所产生的机械刺激可以导致牵张区中微血管和骨组织的生成,而Ang-1可能在牵张区新生血管的形成及稳定和新骨形成中起重要作用。     

HIF—1α在犬下颌骨持续牵张成骨中的表达及与局部血管形成的关系

目的初步探讨缺氧诱导因子-1α（HIF-1α）在犬下颌骨镍钛记忆合金持续牵张成骨中的表达．及HIF--1α在持续牵张成骨中的作用及与局部血管生成的关系。方法成年Beagle犬12只．实验组10只．双侧下颌骨制造1．5cm×1．0cm矩形缺损并在其近中形成相同大小的骨传松盘（采用保留骨松质的骨皮质切开术）．行镍钛记忆合金牵张器持续牵张术，于术后第1、4、7、10、15天取材．每组2只：对照组2只，下颌骨相同部位行相同大小的骨皮质切开术后未行骨牵张术，术后10d取材。RT-PCR法检测HIF-1α mRNA的表达．免疫组化SP法检测HIF—1α、VEGF的蛋白表达，CD34标记内皮细胞检测新生微血管密度（MVD），采用SPSS11．5统计软件分析。结果RT—PCR及免疫组化显示实验组HIF—1α mRNA和HIF-1α蛋白在术后第4、7、10、15天呈阳性表达，两者主要在牵张区的成骨细胞内表达．皆在第7d达最大值。免疫组化显示VEGF在术后第4、7、10、15天呈阳性表达．VEGF在牵张区内皮细胞和成骨细胞内表达，从术后第4天至第10天不断增加，术后第10天达最大值．新生微血管密度在牵张期逐渐升高、术后第7天达峰值（P〈0．05）。对照组HIF—1α mRNA及蛋白和VEGF皆未见明显表达。结论HIF—1α在犬下颌骨持续牵张成骨中高效表达，牵张末期是其发挥作用的关键时期．可能通过上调VEGF的表达，促进牵张成骨局部的血管生成过程。     

Expression of nerve growth factor and vascular endothelial growth factor in the inferior alveolar nerve after distraction osteogenesis

The objective of this study was to evaluate changes occurring in the inferior alveolar nerve (IAN) subsequent to mandibular distraction osteogenesis, with regard to the expression of nerve growth factor (NGF) and vascular endothelial growth factor (VEGF). Unilateral mandibular distractions (0.5mm each, twice per day for 10 days) were conducted on 8 mongrel dogs. Two animals were killed at 7, 14, 28 and 56 days after completion of distraction. The distracted IAN and contralateral control nerve were then harvested and analysed histologically and immunohistochemically. Signs of acute nerve injury, including demyelination, were observed in the distracted IAN on the 7th and 14th day after distraction. At 56 days, the histological features of the distracted IAN were similar to those of the control nerve. The levels of NGF and VEGF expression were significantly elevated on the 7th and 14th day after distraction. NGF was expressed in most of the distracted nerve tissues, but VEGF was primarily detected in Schwann cells and the neurovasorum. VEGF expression had returned to normal but NGF expression was still profoundly elevated 28 days after distraction. NGF expression returned to normal levels at 56 days after distraction. NGF and VEGF appeared to have been elicited from the Schwann cells and damaged nervous tissues, and they may play important roles in the initial healing of damaged nerves. VEGF expression returned to normal more quickly than did NGF expression. This may indicate that hypoxic conditions within the distracted nerve had recovered to normal during the early stages of consolidation. Micro-vessels in the distracted nerve may have recovered more rapidly than did the nerve tissue itself.     

兔下颌骨牵张成骨中神经生长因子对骨痂钙化的作用

目的:观察局部注射神经生长因子(NGF)对下颌骨牵张成骨中新生骨痂钙化的作用。方法:对20只新西兰白兔实施牵张速率为1mm/d的双侧下颌骨牵张成骨。从牵张结束时开始,每只兔的一侧下颌骨新生骨区接受人NGFβ溶液注射(40μg/次,2次),另一侧注射生理盐水作为对照。在固定期第14和28d,新生骨痂经X线侧位片和外径测量后,进行骨沉积速度和钙化面积比定量分析。应用SPSS10.0软件包进行配对t检验,分析NGF处理侧与对照侧之间上述2个钙化指标的差异。结果:与对照侧比较,NGF处理侧的钙化面积比和固定期第1～11d内的骨沉积速度均显著提高(P<0.05),骨痂钙化得到了促进。结论:局部注射人NGFβ溶液能促进兔下颌骨牵张成骨中新生骨痂的钙化,为临床上解决固定期过长的问题提供了一种新的思路。     

Histomorphometric evaluation of short-term changes in masseter muscle after lengthening the rabbit mandible by distraction osteogenesis.

PURPOSE: Structural changes in muscles may affect the process during and after distraction osteogenesis (DO) of the mandible. However, the response of the masticatory muscles is still not well defined after gradual lengthening of the mandible. In this experimental study, short-term structural changes in masseter muscles of the rabbits are evaluated after mandibular DO. MATERIALS AND METHODS: Left mandibles of 10 New Zealand rabbits were lengthened by DO for 7 days in the rate of 1 mm/day. Mandibles of all animals were removed at the end of the consolidation period. Muscle biopsy samples of distracted and contralateral sides were histopathologically investigated, and histomorphometric results were statistically analyzed. RESULTS: Atrophy, hypertrophy, regeneration, and concomitant mild interstitial edema and fibrosis were found more evident in experimental side biopsy samples 30 days after distraction. Histomorphometric analysis revealed a statistically significant decrease in the mean regions of masseter muscle fibers of the distracted sides compared with the control sides (P <.05). CONCLUSION: This experimental study showed that the structure of masseter muscle is influenced during and shortly after mandibular distraction osteogenesis. Atrophic changes of the ipsilateral masseter muscles may be regarded as regenerative response that occurs during and shortly after distraction period.     

下颌骨缺损牵张成骨动物模型的建立

目的建立兔下颌骨缺损牵张成骨动物模型,为进一步研究牵张成骨奠定实验基础。方法25只健康成年兔随机分成6组,实验组5组,每组4只,对照组1组共5只。25只兔均行一侧下颌骨切开截骨术,实验组安置自行设计的下颌骨牵张器,经6 d间歇期后,以每天2次,每次0.4 mm的速度牵张8 d进入固定期,于牵张中期(牵张第4天)、牵张末期(牵张第8天),固定期第2、4、6周分别处死4只动物;对照组术后仅保持缺隙而不牵张,与实验组对应的每个时间点处死1只动物,取下颌骨观察骨愈合情况。结果牵张器牵张效率好,固位稳定,实验组动物的下颌骨被成功牵张,牵张区可见新骨形成。实验对照组表现为不同程度的骨不连及骨缺损。结论本研究建立的兔下颌骨缺损牵张成骨模型是较理想的动物模型。