基因重组人骨形成蛋白-2和聚乳酸复合异位诱导成骨的实验研究

目的：观察基因重组人骨形成蛋白－2（recombinant human Bone Morphofenetic protein-2,rhBMP-2)和聚乳酸（Polylactic acid,PLA)复合形成的活性涂层种植体的异位诱导成骨活性。方法：将rhBMP-2与聚乳酸复合，构建活性涂层种植体，植入兔肌内，于1，4，8周后进行X线、大体观察及组织学观察，检测异位成骨活性。结果：rh-BMP-2/PLA活性复合涂层种植体具有骨诱导能力，PLA为rhBMP-2的良好控释载体。结论：rhBMP-2/PLA涂层具有良好的生物相容性和骨诱导活性，是一种理想的种植体涂层形成。     

活性纳米羟基磷灰石复合胶原聚乳酸材料异位成骨性能研究

目的：探讨既具有骨引导性又具有骨诱导性的活性纳米羟基磷灰石复合胶原/聚乳酸（AnHAC/PLA）材料的异位成骨能力,为该材料作为植骨材料应用于临床打下实验基础。方法：通过扫描电镜观察rhBMP-2与nHAC/PLA材料的复合情况,并将nHAC/PLA、rhBMP-2、AnHAC/PLA材料分别植入小鼠股后肌袋内,术后2周、6周通过X线片、组织学观察、成骨量测定来研究AnHAC/PLA的异位成骨能力。结果：rhBMP-2在nHAC/PLA孔隙中均匀分布,6周时AnHAC/PLA组诱导形成的骨量是rhBMP-2组的10.5倍。结论：AnHAC/PLA材料具有良好成骨能力,nHAC/PLA是rhBMP-2理想的缓释载体。     

rhBMP-2/PLA复合涂层种植体骨内诱导成骨的实验研究

目的：观察基因重组人骨形成蛋白-（recombinanthuman bone morphogenetic protein-2，rhBMP-2）和聚乳酸（polylactic acid，PLA）复合形成的活性涂层种植体骨内诱导成骨活性。方法：将rhBMP-2与聚乳酸复合构建活性涂层种植体，植入兔股骨内，分别于4，8，12，16周处死动物，进行组织学及扫描电镜及组织化学观察，检测其成骨活性。结果：构建的活性涂层种植体具有骨诱导能力，PLA为rhBMP-2的良好控释载体。结论：rhBMP-2/PLA涂层具有良好的生物相容性和骨诱导活性，是一种理想的种植体形式。     

Bone formation at rhBMP-2-coated titanium implants in the rat ectopic model

BACKGROUND: The objective of this study was to evaluate local bone formation at titanium porous oxide (TPO) implant surfaces adsorbed with recombinant human bone morphogenetic protein-2 (rhBMP-2). METHODS: In vitro studies were used to estimate the kinetics of I125-labeled rhBMP-2 released from TPO surfaces with narrow (N) or open (O) pores. Machined/turned titanium (MT) surfaces served as control. The rat ectopic model was used to assess local bone formation. Briefly, TPO-N, TPO-O, and MT disc implants adsorbed with 5, 10, or 20 microg rhBMP-2, respectively, were implanted subcutaneously into the ventral thoracic region in 5-week-old male Long Evans rats. The animals were euthanized at day 14 postsurgery when implants with surrounding tissues were removed, radiographed, and gross observations recorded. The specimens were processed for histologic evaluation using conventional cut-and-grind techniques. TPO implants without rhBMP-2 included in a preliminary evaluation revealed no evidence of bone formation, tissue encapsulation, or vascularity, thus such controls were not further used. RESULTS: TPO and MT implant surfaces adsorbed with 5 microg rhBMP-2 retained 2.3-5.4% rhBMP-2 following immersion and rinse in buffer, and 1.1-2.2% rhBMP-2 following repeated immersions and rinses over 27 days. TPO implants retained the most rhBMP-2 and MT implants retained the least. Explants revealed increased hard tissue formation, tissue encapsulation, and vascularity at TPO compared with MT implants. Radiographic observations were consistent with the explant observations. The histologic analysis showed greater amounts of bone formation, osteoblastic cells, osteoid, marrow, tissue encapsulation, vascularity, and bone voids for implants adsorbed with 10 and 20 microg rhBMP-2, and for TPO implants at the 5-microg rhBMP-2 dose. The histometric analysis revealed significantly greater bone formation at TPO-O than at MT implants at the 5-microg rhBMP-2 dose. All surfaces showed significant bone formation at the 10- and 20-microg dose. CONCLUSIONS: rhBMP-2 adsorbed onto TPO implant surfaces executes an osteoinductive effect including bone contacting the implant surface. This effect is surface- and dose-dependent; the TPO-O surface yielding the most bone at the low discriminating rhBMP-2 dose.     

Implant system for guiding a new layer of bone. Computed microtomography and histomorphometric analysis in the rabbit mandible

Objective: To prove the concept that an implant system with osteoconductive surface characteristics and an osteoinductive scaffold material has the capacity to guide vertical supracrestal bone growth in a rabbit mandible onlay model.
Material and methods: Thirteen adult white New Zealand rabbits each received custom-designed dental implants. All implants had sandblasted, acid-etched (SLA^™) surfaces, with the coronal aspect (3 mm) of each implant was left outside the lateral aspect of posterior mandibular bone, but covered by periosteum, muscle, subcutaneous tissue, and skin. Bone formation around implants placed adjacent to osteoinductive demineralized bone matrix (DBM) scaffolds were compared with contralateral implants without scaffolds in six rabbits using micro-CT imaging. Bone formation around implants with scaffolds from seven additional rabbits was measured using both micro-CT imaging and quantitative histology.
Results: At 8 weeks, new supracrestal bone was seen adjacent to all implants placed with DBM and two implants without DBM. The mean supracrestal bone heights achieved for implants with and without DBM scaffolds as measured by micro-CT was 2.1±0.9 and 0.8±0.9 mm, respectively ( P =0.008). Histomorphometric analysis illustrated that supracrestal bone-to-implant contact for implants with DBM scaffolds was 58.1±14% and that mean supracrestal bone height was 2.4±0.6 mm.
Conclusions: Successful implant-guided supracrestal osteogenesis has been demonstrated in a rabbit model with the combined use of osteoconductive implant surfaces, an osteoinductive scaffold, and a device that prevents soft tissue downgrowth and provides scaffold stabilization.     

Induction of new bone by basic FGF-loaded porous carbonate apatite implants in femur defects in rats

Objectives: The aim of the present study was to investigate whether porous carbonate apatite (CA) containing basic FGF (bFGF) enhances bone augmentation as compared with porous CA alone.
Material and methods: Thirty-six disc-shaped porous CA implants were inserted into femur defects in 36 Wister rats. Porous CA containing 0, 5, or 50 ng of bFGF was placed in the defect. Bone augmentation was evaluated radiographically using micro-CT and histologically by conventional staining at 2 and 12 weeks.
Results: At 2 weeks postoperatively, new bone was evident in the defect sites with porous CA containing either 5 or 50 ng of bFGF. The area of regenerated bone, however, was significantly higher with porous CA containing 5 ng of bFGF than with porous CA containing 50 ng. At 12 weeks postoperatively, no differences in new bone formation were seen between porous CA containing 5 and 50 ng bFGF. Porous CA containing bFGF, however, markedly increased the amount of bone newly formed as compared with porous CA without bFGF. Regardless of the implantation period, TRAP-positive cells were visible around the material, indicating that osteoclast-like cells were resorbing porous CA. In accordance with the evidence, bioresorption of the material increased over time: 6.3–7.8% at 2 weeks to 9.1–11.5% at 12 weeks.
Conclusions: Porous CA is useful as a growth factor carrier and scaffold for bone augmentation.     

A randomized-controlled clinical trial evaluating clinical and radiological outcomes after 3 and 5 years of dental implants placed in bone regenerated by means of GBR techniques with or without the addition of BMP-2

Objective: The aim of this randomized-controlled clinical trial was to evaluate the long-term outcome of implants placed in bone augmented with a xenogenic bone substitute material and a collagen membrane with or without the addition of recombinant human bone morphogenetic protein-2 (rhBMP-2).
Material and methods: Eleven patients received a total of 34 implants placed into sites exhibiting lateral bone defects. In a split mouth design, the defects were randomly treated with the graft material and the collagen membrane either with (test) or without (control) rhBMP-2. The patients were examined 3 and 5 years after insertion of the prosthetic restoration. Student's paired t -test was performed to detect differences between the two groups.
Results: The survival rate at 3 and 5 years was 100% for both groups. The peri-implant soft tissues were stable and healthy without any difference between the two groups. The prosthetic reevaluation demonstrated four loose prosthetic screws during the first 3 years and seven ceramic chippings after 3 and 5 years. The mean distance between the first bone to implant contact to implant abutment junction at 3 years was 1.37 mm (test), 1.22 mm (control), and 1.38 mm (test), and 1.23 mm (control) at 5 years. The difference of <0.2 mm between test and control implants was not statistically significant. The mean change of the marginal bone level between baseline and 5 years ranged from −0.07 mm (mesial, test), −0.11 mm (distal, test), −0.03 mm (mesial, control), to +0.13 mm (distal, control). No statistically significant differences were observed between test and control sites.
Conclusion: Implants placed in bone augmented with and without rhBMP-2 revealed excellent clinical and radiological outcomes after 3 and 5 years.     

基因重组人骨形成蛋白-2与珊瑚/聚乳酸复合异位诱导成骨的实验研究

目的 :观察基因重组人骨形成蛋白 - 2 (rhBMP - 2 )和珊瑚 /聚乳酸形成复合人工骨的异位诱导成骨活性。方法 :把rhBMP - 2和珊瑚 /聚乳酸形成复合人工骨。进行小鼠肌内种植 1、3、6周后 ,组织学观察其异位诱导成骨活性。结果 :rhBMP - 2赋予珊瑚 /聚乳酸骨诱导能力 ,珊瑚 /聚乳酸则充当rhBMP - 2的载体和释放系统 ,对BMP的活性未产生不利影响。与单纯的珊瑚 /聚乳酸相比 ,这种复合人工骨以软骨内成骨的方式诱导成骨。结论 :rhBMP - 2 /珊瑚 /聚乳酸复合人工骨具有良好的生物相容性和骨诱导活性 ,是一种较理想的骨移植替代材料     

应用珊瑚作为重组人骨形成蛋白-2缓释载体的动物实验研究

将大肠杆菌表达的重组人骨形成蛋白-2（rhBMP－2）和珊瑚（coral）复合，制成rhBMP－2／coral复合人工骨，将其植入小鼠股部肌肉内，并以单纯珊瑚植入作对照，术后1、3、6周取材，组织学观察。结果显示：rhBMP－2／coral复合人工骨在植入局部诱导形成骨和软骨，表现出良好的异位诱导成骨能力；珊瑚对rhBMP－2的活性未产生不利影响，是rhBMP－2的良好缓释载体。此复合人工骨可望作为一种新型生物性植骨材料而应用于骨科和颌面外科。     

Effects of implant geometry, surface properties, and TGF-β1 on peri-implant bone response: an experimental study in goats

Objectives: Despite the high success rates in implantology, the desire to use oral implants in more challenging clinical situations drives the need for continuing refinements in implant design and surface properties. In the present study, the effect of implant geometry on implant bone response was evaluated using two geometrically different implant types, i.e. screw type (St) and push-in type(Pi). Furthermore, the potential beneficial effect of an electrosprayed calcium phosphate (CaP) coating, either or not enriched with the osteoinductive growth factor TGF-β1, on the osteogenic response was examined.
Material and methods: A total of 54 implants, divided into six groups ( n =9), were inserted into the femoral condyles of nine goats. After an implantation period of 12 weeks, retrieved specimens were evaluated histologically and histomorphometrically. Measurements were statistically evaluated using SPSS 14.0 and analyzed using a linear regression model.
Results: With respect to implant design, St-implants showed an overall superior biological healing response compared with Pi-implants. Considering surface properties, the deposition of an electrosprayed CaP (2–3 μm) coating onto implants significantly increased the amount of bone–implant contact for both implant types. Additional enrichment of the CaP coating with the osteoinductive growth factor TGF-β1 did not significantly affect peri-implant bone response.
Conclusions: The results of this study indicate that a substantial improvement of the osteogenic response to titanium implants can be achieved by the deposition of an electrosprayed CaP coating. The enrichment of the coating with 1 μg TGF-β1 has only a marginal effect.     

Effect of recombinant human bone morphogenetic protein-2 on bone formation in the acute distraction osteogenesis of rat mandibles

Background: Distraction osteogenesis (DO) is a method of producing new bone directly from the osteotomy site by gradual traction of the divided bone fragments.
Aim: The purpose of the present study was to evaluate histomorphometrically whether acute DO would constitute a viable alternative to the conventional continuous distraction treatment and also to verify the capacity of a recombinant human BMP (rhBMP-2) associated with monoolein gel to stimulate bone formation in the acute distraction process.
Materials and methods: Forty-eight Wistar rats were assigned to three groups: Group 1, treated at a conventional continuous distraction rate (0.5 mm/day), Group 2, treated with acute distraction of 2.5 mm at the time of the surgical procedure, and Group 3, subjected to acute distraction associated with rhBMP-2. The animals from each experimental group were killed at the end of the second or fourth post-operative weeks and the volume fraction of newly formed bone trabeculae was estimated in histological images by a differential point-counting method.
Results: The results showed that after 2 and 4 weeks, bone volumes in the rhBMP-2 group were significantly higher than in the other groups ( P <0.05), but no significant difference was observed in the volume fraction of newly formed bone between the continuous and acute DO groups.
Conclusion: In conclusion, the study indicates that rhBMP-2 can enhance the bone formation at acute DO, which may potentially reduce the treatment period and complications related to the distraction procedure.     

Restoration of occlusal function using osseointegrated implants in the canine mandible reconstructed by rhBMP-2

Abstract: Bone morphogenetic proteins have been found to be one of the most promising osteoinductive substances and they are expected to be utilized clinically for the reconstruction of defective mandibles. However, newly formed bone induced by recombinant human bone morphogenetic protein-2 (rhBMP-2) has not yet been proven able to withstand the masticatory force applied by oral implants. In this study, we examined the qualitative changes in an rhBMP-2-induced mandible from the functional force of osseointegrated oral implants. Segmental (30 mm) bone defects were created in the mandibles of beagles. A poly D,L-lactic coglycolic acid-coated gelatin sponge impregnated with rhBMP-2 was grafted to the resected canine mandible. The new bone was formed 8 weeks after surgery and the Brånemark system fixtures were implanted into the reconstructed mandible. After another 8 weeks, the prosthesis was placed over the oral implants. The prosthesis was maintained in occlusion with the opposing natural dentition for 0, 4, 12, 24, or 48 weeks before the animal was euthanized. The quality of regenerated bone was then evaluated histologically and the osseointegration ratio between oral implants and the bonemeasured. During the first 4 weeks, the ratio remarkably increased from 48.9% to 64.5%. After 48 weeks, the ratio approached about 74.5%. The bone loaded for 48 weeks had undergone extensive remodeling and consolidation; its quality was better and maturer than that of bone that was not loaded. These results indicated that the newly formed bone induced by rhBMP-2 was able to withstand the masticatory force applied by oral implants and had become as functionally mature as a natural bone.     

Sinus floor augmentation with recombinant human growth and differentiation factor-5 (rhGDF-5): a pilot study in the Goettingen miniature pig comparing autogenous bone and rhGDF-5

Aim: The aim of this study was to test the hypothesis that recombinant human growth and differentiation factor-5 (rhGDF-5) in combination with a β-tricalcium phosphate (β-TCP) scaffold material results in superior bone formation in sinus floor augmentations in miniature pigs compared with a particulated autogenous bone graft combined with the scaffold material.
Material and methods: Six adult female Goettingen minipigs underwent a maxillary sinus floor augmentation procedure. In a split-mouth design, the sinus floors were augmented with β-TCP mixed with autogenous cortical bone chips, in a ratio of approximately 1 : 1, on one side. The contralateral test site was augmented using β-TCP coated with two concentrations of rhGDF-5 (400 μg rhGDF-5/g β-TCP or 800 μg rhGDF-5/g β-TCP; three animals in each case). Simultaneously, one dental implant was inserted into each sinus floor augmentation. After 12 weeks, a histological and histomorphometric assessment of non-decalcified histological specimens was made.
Results: There were significantly higher mean values of volume density of newly formed bone using β-TCP coated with two concentrations of rhGDF-5 (400 μg: 32.9%; 800 μg: 23.9%) than with the corresponding control (autogenous bone/β-TCP) (14.6%, 12.9%) ( P =0.012, P =0.049). The bone-to-implant contact rates (BIC) were significantly enhanced in test sites (400 μg: 84.2%; 800 μg: 69.8%) compared with the corresponding control sites (24.8%, 40.8%) ( P =.027, P =.045).
Conclusion: rhGDF-5 delivered on β-TCP significantly enhanced bone formation compared with β-TCP combined with autogenous bone in sinus lift procedures in miniature pigs.     

基因重组人骨形成蛋白-2和牛骨形成蛋白异位诱导成骨的比较

目的：观察基因重组人骨形成蛋白-2（rhBMP-2)和牛骨形成蛋白（bBMP)分别与珊瑚/聚乳酸形成复合人工骨的异位诱导成骨活性，同时比较两种骨形成蛋白的成骨效率，方法：把rhBMP-2和bBMP分别与珊瑚/聚乳酸形成复合人工骨，进行小鼠肌内种植1、3、6周后，组织学观察和组织形态测量，比较其异位诱导成骨活性。结果：rhBMP-2和bBMP存在骨诱导差异，rhBMP-2诱导成骨量相对较少但血管，骨髓含量丰富，bBMP则相反，结论：两种BMP都具有良好的诱骨活性，但在居骨量和血管，骨髓样组织的形成量上有明显不同。     

重组人骨形成蛋白-2结合胶原膜在兔颅骨引导骨再生模型中的成骨效应研究

目的    探讨重组人骨形成蛋白-2（rhBMP-2）与胶原膜靶向结合后在兔颅骨引导骨再生（GBR）模型中的成骨效应。方法    将20只普通级雌性健康新西兰大白兔随机分成2周组和6周组,每组10只。所有大白兔均制备颅骨GBR模型,在颅顶骨植入4个钛筒,分别盖rhBMP-2/CBD胶原膜（rhBMP-2/CBD胶原膜组）、rhBMP-2胶原膜（rhBMP-2胶原膜组）、胶原膜（胶原膜组）和不盖膜（空白组）。分别在2周和6周时处死各对应组的大白兔,取样制作硬组织切片和石蜡切片,染色后进行组织学观察。结果    2周时可见胶原膜阻挡了纤维组织的长入,4组钛筒上层均无新骨生成,其中rhBMP-2/CBD胶原膜组钛筒顶端毛细血管增生量明显较其余3组多。6周时可见rhBMP-2/CBD胶原膜组钛筒上层大量新骨生成,与来源于颅骨骨面的新骨界限明显,而其余3组钛筒顶端未见新骨生成。结论    rhBMP-2与胶原膜靶向结合可形成具有骨诱导性的胶原膜,缓释rhBMP-2使胶原膜下方大量新骨生成,表层成骨可阻止纤维组织的长入和防止植骨床的塌陷,使成骨速度加倍。     

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目的 探讨重组人骨形成蛋白-2(rhBMP-2)与胶原膜靶向结合后在兔颅骨引导骨再生(GBR)模型中的成骨效应。方法 将20只普通级雌性健康新西兰大白兔随机分成2周组和6周组,每组10只。所有大白兔均制备颅骨GBR模型,在颅顶骨植入4个钛筒,分别盖rhBMP-2/CBD胶原膜(rhBMP-2/CBD胶原膜组)、rhBMP-2胶原膜(rhBMP-2胶原膜组)、胶原膜(胶原膜组)和不盖膜(空白组)。分别在2周和6周时处死各对应组的大白兔,取样制作硬组织切片和石蜡切片,染色后进行组织学观察。结果 2周时可见胶原膜阻挡了纤维组织的长入,4组钛筒上层均无新骨生成,其中rhBMP-2/CBD胶原膜组钛筒顶端毛细血管增生量明显较其余3组多。6周时可见rhBMP-2/CBD胶原膜组钛筒上层大量新骨生成,与来源于颅骨骨面的新骨界限明显,而其余3组钛筒顶端未见新骨生成。结论 rhBMP-2与胶原膜靶向结合可形成具有骨诱导性的胶原膜,缓释rh BMP-2使胶原膜下方大量新骨生成,表层成骨可阻止纤维组织的长入和防止植骨床的塌陷,使成骨速度加倍。     

Effect of rhBMP-2 with PLGA/gelatin sponge type (PGS) carrier on alveolar ridge augmentation in dogs

Summary  Recombinant human bone morphogenetic protein-2 has been shown to promote bone formation because of its osteoinductive property. The purpose of this study was to evaluate the efficacy of rhBMP-2 delivered on a poly ( d , l -lactic-co-glycolic acid) copolymer/gelatin sponge (PGS) in vertical alveolar ridge augmentation on height-reduced edentulous mandible to verify the retention of rhBMP-2 withstanding the pressure of soft tissues. Coronal defects of the alveolar bone were created in six adult beagle dogs. After a healing period of 9 weeks, PGSs with or without rhBMP-2 (0 or 0·4 mg mL⁻¹) were implanted on the defects(6 mm in height, 30 mm in length, 8 mm in width). Sixteen weeks after implantation, the bone mineral content (BMC) and the total bone area were measured by peripheral quantitative computed tomography. The BMC and the total bone area of the defect sites with rhBMP-2 group were significantly greater (133 ± 33 mg mm⁻¹, 277 ± 54 mm², respectively) than those of the control group (80 ± 19 mg mm⁻¹, 155 ± 49 mm², respectively) ( P  <   0·01, P  <   0·0001, respectively; paired t -test). From the histological analyses, the height of newly formed bone in the experimental group was greater than that of the control group (4·3 ± 0·9 mm, 0·22 ± 0·28 mm, P  <   0·0001, n  = 6, paired t -test). These results indicate that PGS has characteristics of effective bone graft substitutes for implantation of rhBMP-2 on vertical alveolar ridge augmentation in huge defect of mandibles in dogs.     

rhBMP-2、胶原、珊瑚复合骨诱导骨形成生物活性的实验研究

目的：研究珊瑚、胶原、ｒｈＢＭＯＰ－２复合骨异位诱导新骨形成的活性和载体在体内降解情况。方法：选择珊瑚和１型胶 为ｒｈＢＭＰ－２载体,采用肌袋异位成骨的动物模型,通过大体观察、组织测量等手段,研究复合骨诱导新骨形成的特点、珊瑚降解的过程。结果：ｒｈＢＭＰ－２、珊瑚和胶原复合骨诱导骨组织形成,在一定范围内随作用时间延长新骨形成量持续增加,其中ｒｈＢＭＰ－２、胶原、珊瑚复合骨具有骨引导性和骨诱导性,珊