Guided bone regeneration in rat mandibular defects using resorbable poly(trimethylene carbonate) barrier membranes

The present study evaluates a new synthetic degradable barrier membrane based on poly(trimethylene carbonate) (PTMC) for use in guided bone regeneration. A collagen membrane and an expanded polytetrafluoroethylene (e-PTFE) membrane served as reference materials. In 192 male Sprague-Dawley rats, a standardized 5.0mm circular defect was created in the left mandibular angle. New bone formation was demonstrated by post mortem micro-radiography, micro-computed tomography imaging and histological analysis. Four groups (control, PTMC, collagen, e-PTFE) were evaluated at three time intervals (2, 4 and 12 weeks). In the membrane groups the defects were covered; in the control group the defects were left uncovered. Data were analysed using a multiple regression model. In contrast to uncovered mandibular defects, substantial bone healing was observed in defects covered with a barrier membrane. In the latter case, the formation of bone was progressive over 12 weeks. No statistically significant differences between the amount of new bone formed under the PTMC membranes and the amount of bone formed under the collagen and e-PTFE membranes were observed. Therefore, it can be concluded that PTMC membranes are well suited for use in guided bone regeneration.     

The role of rhFGF-2 soaked polymer membrane for enhancement of guided bone regeneration

Abstract

The purposes of this study are to confirm the role of Fibroblast Growth Factor-2 (FGF-2) in bone regeneration by adding various concentrations of FGF-2 to the collagen membrane and applying it to the Biphasic Calcium Phosphate (BCP) bone graft site for guided bone regeneration, to explore the potential of collagen membrane as FGF-2 carrier, and to determine the optimum FGF concentration for enhancement of bone regeneration. Four bone defects of 8 mm in diameter were created in 18 New Zealand rabbit calvaria. After BCP bone graft, graft material was covered with collagen membranes adding various concentration of FGF-2. The concentration of FGF-2 was set at 1.0, 0.5, 0.1 mg/ml, and same amount of saline was used in the control group. To confirm the bone regeneration over time, six New Zealand rabbits were sacrificed each at 2, 4, and 12 weeks, and the amounts of new bone and residual bone graft material were analyzed by histologic and histomorphometric analysis. Qualitative analyses are also conducted through immunohistochemistry, Tetrate-resistant acid phosphatase (TRAP) stain and Russell-Movat pentachrome stain. As the healing period increased, the formation of new bone increased and the amount of residual graft material decreased in all experimental groups. Immunohistochemistry, TRAP staining and pentachrome staining further showed that the addition of FGF-2 promoted bone regeneration in all experimental groups. It was also confirmed that polymer collagen membrane can be used as a useful carrier of FGF-2 when enhanced early stage of new bone formation is required.     

Alveolar bone regeneration using poly-(lactic acid-co-glycolic acid-co-{varepsilon}-caprolactone) porous membrane with collagen sponge containing basic fibroblast growth factor: An experimental study in the dog

The aim of this study was to evaluate the effects of combining porous poly-lactic acid-co-glycolic acid-co-ε-caprolactone (PLGC) as a barrier membrane and collagen sponge containing basic fibroblast growth factor (bFGF) to promote bone regeneration in the canine mandible. In six beagle dogs, two lateral bone defects per side were created in the mandible. The lateral bone defects on the left side were treated with a PLGC membrane plus a collagen sponge containing bFGF. In half of these, the collagen sponge contained 50?μg of bFGF. In the other half, it contained 250?μg of bFGF. As a control, we treated the right-side bone defects in each animal with the same PLGC membrane but with a collagen sponge containing phosphate buffered saline. Computed tomography (CT) images were recorded at 3 and 6 months post-op to evaluate regeneration of the bone defects. After a healing period of 6 months, whole mandibles were removed for micro-CT and histological analyses. The post-op CT images showed that more bone had formed at all experimental sites than at control sites. At 3 months post-op, the volume of bone at defect sites covered with PLGC membrane plus 250?μg of bFGF was significantly greater than it was at defect sites covered with PLGC membrane plus 50?μg of bFGF. At 6 months post-op, however, this difference was smaller and not statistically significant. Micro-CT measurement showed that the volume of new bone regenerated at bone-defect sites, covered with PLGC membrane plus bFGF, was significantly greater than that of control sites. However, the presence or absence of bFGF in the collagen sponge did not significantly affect the bone density of new bone. These results suggest that the macroporous bioresorbable PLGC membrane plus collagen sponge containing bFGF effectively facilitates healing in GBR procedures.     

Evaluation of the cytocompatibility hemocompatibility in vivo bone tissue regenerating capability of different PCL blends

In this study, the optimized formulations of polycaprolactone (PCL) combined with poly(lactic-co-glycolic acid) (PLGA), gelatin (GEL), and biphasic calcium phosphate (BCP) were analyzed in terms of cytocompatibility with bone-related cells, hemocompatibility, and in vivo bone-regenerating capacity to determine their potentials for bone tissue regeneration. Fiber morphology of PCL/GEL and PCL/BCP electrospun mats considerably differs from that of the PCL membrane. Based on the contact angle analyses, the addition of GEL and PLGA was shown to reduce the hydrophobicity of these membranes. The assessment of in vitro cytocompatibility using MC3T3-E1 cells indicated that all of the membranes were suitable for pre-osteoblast proliferation and adhesion, with PCL/BCP having a significantly higher reading after seven days of incubation. The results of the in vitro hemocompatibility of the different fibrous scaffolds suggest that coagulation and platelet adhesion were higher for hydrophobic membranes (PCL and PCL/PLGA), while hemolysis can be associated with fiber morphology. The potential of the membranes for bone regeneration was determined by analyzing the microCT data and tissue sections of samples implanted in 5?mm sized defects (one and two months). Although all of the membranes were suitable for pre-osteoblast proliferation, in vivo bone regeneration after two months was found to be significantly higher in PCL/BCP (p?相似文献   

A histological evaluation for guided bone regeneration induced by a collagenous membrane

This study was designed to evaluate the histological changes during ossification and cellular events including osteogenic differentiation responding to collagenous bioresorbable membranes utilized for GBR. Standardized artificial bony defects were prepared at rat maxillae, and covered with a collagenous bioresorbable membrane. These animals were sacrificed at 1, 2, 3 and 4 weeks after the GBR-operation. The paraffin sections were subject to tartrate resistant acid phosphatase (TRAP) enzyme histochemistry and immunohistochemistry for alkaline phosphatase (ALP), osteopontin (OP) and osteocalcin (OC). In the first week of the experimental group, woven bone with ALP-positive osteoblasts occupied the lower half of the cavity. The collagenous membrane included numerous ALP-negative cells and OP-immunoreactive extracellular matrices. At 2 weeks, the ALP-, OP- and OC-immunoreactivity came to be recognizable in the region of collagenous membrane. Since ALP-negative soft tissue separated the collagenous membrane and the new bone originating from the cavity bottom, the collagenous membrane appeared to induce osteogenesis in situ. At 3 weeks, numerous collagen fibers of the membrane were embedded in the adjacent bone matrix. At 4 weeks, the membrane-associated and the cavity-derived bones had completely integrated, showing the same height of the periosteal ridge as the surrounding alveolar bones. The collagen fibers of a GBR-membrane appear to participate in osteogenic differentiation.     

Healing of alveolar bone in resorbable and non-resorbable membrane-protected defects. A histologic pilot study in dogs

Two main types of membrane barriers are used for bone regeneration, non-resorbable and resorbable. Polytetrafluorethilene non-resorbable membranes have been extensively studied but they require a second surgical step for removal. Although polylactic acid (PLA) resorbable membranes avoid this problem, they have not been sufficiently evaluated on bone defects. The purpose of this pilot study was to compare the healing events of bone regeneration after placement of non-resorbable or resorbable membranes and to evaluate the amount of newly formed bone 2 and 4 months after membrane placement. Mandibular second, third and fourth premolars of four adult mongrel dogs were extracted bilaterally. Two rectangular bone defects (8 mm corono-apical and 12 mm mesial-distal) were created bilaterally 3 months after tooth extractions. Each dog received two resorbable membranes and one non-resorbable membrane; one defect was left untreated. Two dogs were killed at 2 months and the remaining two at 4 months following surgery. Undecalcified sections were obtained and stained with toluidine blue and pyronin G. Histomorphometric analysis was performed using the NIH Image software. Newly formed bone was observed under both resorbable and non-resorbable membranes. The amount of regenerated bone was similar between both treatments at 2 and 4 months after surgery. At 2 months, the newly formed bone was still immature whereas at 4 months some areas of woven bone were observed. The bone formation observed in the untreated defects was significantly lower than that observed in both resorbable and non-resorbable membrane-protected defects. In summary, the present study suggests that PLA membranes can yield good results when used on bone defects while avoid a second surgical procedure.     

Bone regeneration in segmental defects with resorbable polymeric membranes: IV. Does the polymer chemical composition affect the healing process?

Diaphyseal segmental defects 10 mm in length in the radii of 36 skeletally mature rabbits were covered with tubular microporous membranes prepared from poly(L/D-lactide) (18 rabbits) and poly(L/DL-lactide) (18 rabbits) to determine whether chemical composition of the membrane affected the bone healing in the defect. The results of a previous study in which similar defects of the rabbits radii were not covered with membranes or covered with poly(L-lactide) membranes were used as controls. The control defects were rapidly filled with overlying muscle and soft tissues, producing a radio-ulnar synostosis. The osseous activity of control defects was limited to the bone ends. The defects covered with membranes were progressively filled with new bone. At 1 year, complete bone regeneration in the defects covered with the poly(L/D-lactide) membrane was found in 16 cases, no regeneration in 1 animal and pseudoarthrosis in 1 animal. For the poly(L/DL-lactide) membrane there was complete bone regeneration in 17 cases (1 animal died during surgery). The quality of the interface between the new bone and the membrane seemed to be affected by the chemical structure of the polylactides used for membranes preparation. For poly(L/D-lactide), the connective tissue layer entirely separated the new bone from the polymeric membrane. This has been observed before for poly(L-lactide) membranes. In the case of poly(L/DL-lactide) the new bone was formed in some places in direct contact with the membrane and the membrane fragments were osteointegrated. The differences in chemical composition of the polylactide membranes did not have an evident effect on the bone regeneration process in segmental defects of the rabbit radii.     

Effects of various implant materials on regeneration of calvarial defects in rats

The purpose of the present study was to determine the best implant material, the best conditions to substitute absorbable membrane for non-absorbable membrane, and the factors influencing guided regeneration of critical size defects using experimental rats. An 8-mm circular transosseous calvarial bony defect was made and implant materials, such as demineralized freeze-dried bone (DFDB), absorbable membrane (BioMesh; Samyang Co., Seoul Korea), non-absorbable membrane (Millipore filter; Micro Filtration System, MA, USA) or a combination of these materials, was placed on the defect. As for the results of sequential time-based guided bone regeneration, histological, histochemical, immunohistochemical and histomorphometric aspects were observed, and a statistical comparative analysis was performed, with control group of a soft tissue flap. Bone formation was significantly enhanced when DFDB was retained within the defect with a protective absorbable membrane. Inframembranous DFDB-filling was required to prevent membrane collapse and to preserve spaces for bone regeneration. The absorbable membrane which was recommended to overcome the disadvantages of the non-absorbable membrane should remain intact for more than 5 weeks in order for it to be effective. The macrophages recruited by grafts were involved partly in decreasing bone regeneration via the sequential events of releasing fibronectin, and in chemotactic effect of the fibronectin to fibroblasts and collagen lay-down. Thus, the activity of new bone formation was dependent upon the physical barrier effect of the membrane, such as the preserving ability to secure spaces and the suppression ability of early infiltration of collagen and epithelium, inducible ability of inflammation by the implant material, and potential in guiding bone regeneration of the grafts.     

可降解聚羟基丁酸酯-羟基戊酸酯的共聚物膜

背景：聚羟基丁酸/羟基戊酸共聚酯已用于构建心脏生物瓣膜,但不知是否可作为骨再生引导膜？ 目的：观察聚羟基丁酸/羟基戊酸共聚酯膜的生物相容性,并评价其成骨能力。 方法：采用MTT法检测100%,75%,50%,25%聚羟基丁酸/羟基戊酸共聚酯材料浸提液对犬骨髓间充质干细胞相对增殖度的影响,并评价其细胞毒性;在犬胫骨缺损模型左右两侧远心端骨缺损上方覆盖聚羟基丁酸/羟基戊酸共聚酯膜作为实验组,在近心端仅以骨膜瓣复位作为对照组。 结果与结论：100%,75%,50%,25%聚羟基丁酸/羟基戊酸共聚酯膜的细胞毒性分级为0~1级,对骨髓间充质干细胞的生长及增殖无毒性;实验组术后第2周即可见新骨形成,12周时骨缺损区已完全被新骨充填,骨修复质量明显优于对照组。表明聚羟基丁酸/羟基戊酸共聚酯膜具有良好的生物相容性,对骨髓间充质干细胞无明显毒性,引导成骨能力强。     

Enhanced osteogenesis and angiogenesis by PCL/chitosan/Sr-doped calcium phosphate electrospun nanocomposite membrane for guided bone regeneration

Abstract

Membranes play pivotal role in guided bone regeneration (GBR) technique for reconstruction alveolar bone. GBR membrane that is able to stimulate both osteogenic and angiogenic differentiation of cells may be more effective in clinic practice. Herein, we fabricated the Sr-doped calcium phosphate/polycaprolactone/chitosan (Sr-CaP/PCL/CS) nanohybrid fibrous membrane by incorporating 20?wt% bioactive Sr-CaP nanoparticles into PCL/CS matrix via one-step electrospinning method, in order to endow the membrane with stimulation of osteogenesis and angiogenesis. The physicochemical properties, mechanical properties, Sr²⁺ release behavior, and the membrane stimulate bone mesenchymal stem cell (BMSCs) differentiation were evaluated in comparison with PCL/CS and CaP/PCL/CS membranes. The SEM images revealed that the nanocomposite membrane mimicked the extracellular matrix structure. The release curve presented a 28-day long continuous release of Sr²⁺ and concentration which was certified in an optimal range for positive biological effects at each timepoint. The in vitro cell culture experiments certified that the Sr-CaP/PCL/CS membrane enjoyed excellent biocompatibility and remarkably promoted rat bone mesenchymal stem cell (BMSCs) adhesion and proliferation. In terms of osteogenic differentiation, BMSCs seeded on the Sr-CaP/PCL/CS membrane showed a higher ALP activity level and a better matrix mineralization. What’s more, the synergism of the Sr²⁺ and CaP from the Sr-CaP/PCL/CS membrane enhanced BMSCs angiogenic differentiation, herein resulting in the largest VEGF secretion amount. Consequently, the Sr-CaP/PCL/CS nanohybrid electrospun membrane has promising applications in GBR.     

生物源性和无机源性骨替代材料修复颅骨缺损的组织学变化

背景：目前有关生物源性和无机骨组织替代材料的研究时有报道,但是选择这两种材料对于颅骨缺损病理改变的骨增量和成骨效果的差异尚无定论。 目的：比较兔颅骨缺损再生修复中应用生物源性和无机源性骨组织替代材料引导骨组织再生的能力。 方法：建立成年新西兰兔颅顶骨3个直径8 mm洞型骨缺损模型,前方和后方洞型骨缺损区分别采用无机源性Bio-Oss骨粉与生物源性天博固齿骨粉填充并用胶原生物膜覆盖。中间洞型骨缺损区仅用胶原生物膜覆盖不做其他处理,作为对照组。 结果与结论：术后12,16,24周通过Masson三色染色图像分析显示,无机源性骨粉组和生物源性骨粉组较空白对照组新生骨量明显增加,且生物源性骨粉组新生骨量明显多于无机源性骨粉组 (P ≤ 0.05)。可见无机源性与生物源性骨粉均可起到引导新骨再生修复骨缺损的作用,但生物源性骨粉修复骨缺损效果优于无机源性骨粉。     

Healing pattern of bone defects covered by different membrane types--a histologic study in the porcine mandible

Few investigations on guided bone regeneration (GBR) focus on the behaviour of tissues adjacent to barrier membranes. This study was conducted to (1) evaluate the barrier function potential of different resorbable and nonresorbable membranes for GBR, (2) investigate their structural changes after different intervals, and (3) characterize tissue composition and reaction adjacent to the barrier by qualitative histologic evaluation. Seven barriers for GBR were used per animal (made of dense or expanded polytetrafluoroethylene (d/ePTFE), titanium, polyetherurethane, collagen and two polylactide-polyglycolide-/-trimethylenecarbonate-co-polymers (PLPG, LPGTC) in standardized defects not exceeding the critical size) without using bone substitution material or autogenous bone at the right inferior margin of the mandibles of six domestic pigs. Samples of the defect areas with membranes were harvested after 2 days (one animal), 4 and 8 (two animals, each) and 12 weeks (one animal), respectively. The healing of bone defects was completed in all animals after 12 weeks. Nonresorbable barriers prevented the soft tissue in-growth into standardized defects. Thinner layers of fibrous tissue were seen underneath the dense and rigid barriers (dPTFE, titanium) when compared with collagen and PLPG/LPGTC, in which soft-tissue plugs occupied the crestal defect portion. PLPG-/LPGTC-barriers underwent structural changes after 4 weeks and revealed blistered central layers, whereas structural changes were not evident in nonresorbable barriers. The degradation of PLPG-/LPGTC-membranes was present with in-growth of fibres, vessels, and cells. Using collagen or synthetic polymer barriers for GBR, the application of bone or bone substitutes to prevent membrane prolapse into the defect is suggested.     

Asymmetric Composite Membranes from Chitosan and Tricalcium Phosphate Useful for Guided Bone Regeneration

Abstract

To fulfill the properties of barrier membranes useful for guided bone tissue regeneration in the treatment of periodontitis, in this study a simple process combining lyophilization with preheating treatment to produce asymmetric barrier membranes from biodegradable chitosan (CS) and functional β-tricalcium phosphate (TCP) was proposed. By preheating TCP/CS (3:10, w/w) in an acetic acid solution at 40°C, a skin layer that could greatly increase the mechanical properties of the membrane was formed. The asymmetric membrane with a skin layer had a modulus value almost 4-times that of the symmetric porous membrane produced only by lyophilization. This is beneficial for maintaining a secluded space for the bone regeneration, as well as to prevent the invasion of other tissues. The subsequent lyophilization at ?20°C then gave the rest of material an interconnected pore structure with high porosity (83.9–90.6%) and suitable pore size (50–150?μm) which could promote the permeability and adhesiveness to bone cells, as demonstrated by the in vitro cell-culture of hFOB1.19 osteoblasts. Furthermore, the TCP particles added to CS could further increase the rigidity and the cell attachment and proliferation of hFOB1.19. The TCP/CS asymmetric composite membrane thus has the potential to be used as the barrier membrane for guided bone regeneration.     

生物活性骨诱导再生膜的研制

研制一种具有生物活性的骨诱导再生膜。采用溶剂挥发法及冷冻干燥制备 PL A 胶原 rh BMP- 2复合膜 ,对膜作力学性能测试 ,SEM表面特征观察 ,失重率及黏均分子量测定 ,体内外降解性评价 ;复合膜植入兔肌间隔 ,术后 1、2、3、6月取标本 ,光镜评价组织相容性和骨诱导活性。结果显示 PL A 胶原 rh BMP- 2膜呈双面不对称并携带生物活性因子 ,拉伸强度 36 .4 MPa,断裂伸长率 2 .3% ;膜形态体内保持 3个月 ,体外 12个月或体内 6个月膜完全降解 ;复合膜随植入时间延长 ,局部炎症反应减轻 ,具有异位骨诱导性。由此可见 ,PL A 胶原 rh BMP- 2膜是一种较理想的能控释生物活性因子的骨诱导活性再生膜。     

Molded porous poly (L-lactide) membranes for guided bone regeneration with enhanced effects by controlled growth factor release

The aim of this study was to develop platelet-derived growth factor (PDGF-BB) loaded moldable porous poly (L-lactide) (PLLA)-tricalcium phosphate (TCP) membranes for guided bone regeneration (GBR) therapy. The membranes were designed to fit various types of bone defect sites. PDGF-BB-dissolved PLLA-TCP in methylene chloride-ethyl acetate solution was cast on a dome shaped metallic mold to fabricate a model membrane. The release rate of PDGF-BB, the osteoblast attachment test, and guided bone regeneration potential were evaluated with PDGF-BB-loaded PLLA-TCP membranes. Regular pores were generated throughout the membrane mainly due to phase inversion of PLLA-methylene chloride-ethyl acetate solution. A therapeutic amount of PDGF-BB was released from the membrane. The release rate could be controlled by varying the initial loading content of PDGF-BB. A significant amount of cells attached onto the PDGF-BB-loaded membrane rather than onto the unloaded membrane. Dome shaped bone formation was achieved in rabbit calvaria at 4 weeks. This indicated that restoration of bone defects to the bone's original shape can be made possible by using molded membranes, which guide bone regeneration along with providing sufficient spaces. Bone forming efficiency was increased remarkably due to PDGF-BB release from PLLA-TCP membranes. These results suggested that the PDGF-BB releasing molded PLLA-TCP membrane may potentially improve GBR efficiency in various types of bone defects.     

Application of a Novel Resorbable Membrane in the Treatment of Calvarial Defects in Rats

Diplen-Gam (DG) is a novel absorbable guided bone regeneration (GBR) membrane. This study was designed to evaluate the capacity of bone repair of DG compared with that of Bio-Gide (BG). Critical size defects were created in both sides of the calcarium of 36 Sprague–Dawley rats. Defects were assigned to six groups and each group was subjected to one of the following treatments: (A1) unfilled defects, (A2) Bio-Oss (BO) grafts, (B1) DG membrane, (B2) BG membrane, (C1) DG membrane + BO grafts and (C2) BG membrane + BO grafts. The animals were killed at 2, 4, 8 and 12 weeks after the operation. The defects and surrounding tissues were examined by gross observation and X-ray examination. The paraffin sections were subjected to HE (hematoxylin and eosin) staining and IHC (immunohistochemistry) for bone morphogenetic protein-2 (BMP-2). The X-rays showed that, at 12 weeks, the DG and BG group exhibited more new bone formation than CSD blank group did; the BG group exhibited more new bone formation than the DG group did (t = 5.240, P = 0.035), the BG + BO group showed no significant differences in bone formation compared with the DG + BO group (t = 1.246, P = 0.339). By IHC staining, BMP-2-positive results could be seen inside the DG membrane, on the surface of the new bone, and inside the new bone. It can be suggested that BG membrane achieved better effects in guided bone regeneration compared with DG membrane. No significant differences were found between the two membranes in their bone healing ability when they are used with BO. Therefore, DG membrane shows clinical effectiveness, but should be used in combination with bone substitute.     

Attachment,proliferation and collagen type I mRNA expression of human gingival fibroblasts on different biodegradable membranes

Abstract

The purpose of this study was to investigate adhesion, proliferation and type I collagen (COL I) mRNA expression of gingival fibroblasts on different membranes used in periodontal applications. Collagen (C), acellular dermal matrix (ADM) and polylactic acid; polyglycolic acid; lactide/glycolide copolymer (PLGA) biodegradable membranes were combined with gingival fibroblasts in culture and incubated for 48?h. Cell adhesion was examined with scanning electron and confocal microscopy. MTT assay was used to measure proliferation. COL I mRNA expression was assessed using quantitative-polymerase chain reaction (QPCR). The PLGA group exhibited the lowest cell survival on day 5 and 10, and lowest cell proliferation on days 5, 10 and 14. While cell proliferation was similar in C and ADM groups, the C membrane showed a slightly greater increase in viable cells to day 10. Confocal and scanning electron microscopy confirmed the results of proliferation and MTT assays. The highest COL I mRNA expression was noted in the PLGA membrane group when compared to the C (p?<?0.01) and ADM (p?<?0.05) membrane groups. These data revealed that adherence and proliferation of primary gingival fibroblasts on collagen-based C and ADM membranes is better than that seen with PLGA membranes, and thus may be preferable in the treatment of gingival recession defects.     

Effect of naringin collagen graft on bone formation

Naringin is a flavonoid available commonly in citrus fruits and is also a HMG-CoA reductase inhibitor. Our laboratory compared the amount of new bone produced by naringin in collagen matrix to that produced by bone grafts and collagen matrix. Twenty bone defects, 5 mm x 10 mm were created in the parietal bone of 14 New Zealand White rabbits. In the experimental group, 5 defects were grafted with naringin solution mixed with collagen matrix, 5 defects were grafted with autogenous endochondral bone. In the control groups, 5 defects were grafted with collagen matrix alone (active control) and 5 were left empty (passive control). Animals were killed on day 14 and the defects were dissected and prepared for histological assessment. Serial sections were cut across each defect. Quantitative analysis of new bone formation was made on 150 sections (50 sections for each group) using image analysis. A total of 284% and 490% more new bone was present in defects grafted with naringin in collagen matrix than those grafted with bone and collagen, respectively. No bone was formed in the passive control group. In conclusion, naringin in collagen matrix have the effect of increasing new bone formation locally and can be used as a bone graft material.     

脱钙骨基质与骨髓间充质干细胞共培养关节腔内的成软骨活性

背景：将骨髓间充质干细胞附着到支架材料上再植入关节软骨缺损处,细胞不但不消失,而且可形成新的软骨。 目的：观察同种异体脱钙骨基质与骨髓间充质干细胞共培养在关节内的成软骨活性。 方法：在54只青紫蓝兔单侧膝关节制作关节软骨全层缺损模型,随机分组：实验组在缺损处植入自体骨髓间充质干细胞与同种异体脱钙骨基质复合物,对照组缺损处仅植入同种异体脱钙骨基质,空白对照组未植入任何物质。 结果与结论：植入后12周,实验组缺损处修复组织呈软骨样,表面光滑平坦,与周围软骨整合的软骨细胞更为成熟,修复组织与软骨下骨结合牢固;修复组织的细胞为透明软骨样细胞,柱状排列,Ⅱ型胶原染色阳性,与周围软骨及软骨下骨整合良好,且实验组组织学评分优于对照组和空白对照组 (P < 0.01)。对照组缺损处修复组织呈纤维样,与周围软骨未结合,空白对照组缺损区无修复组织,两组均无Ⅱ型胶原染色阳性表达。表明同种异体脱钙骨基质与骨髓间充质干细胞共培养后植入膝关节可形成软骨样组织,有效修复关节软骨缺损。     

Bone Regeneration by a Combination of Osteopromotive Membranes with Different BMP Preparations: A Review

The aim of these studies was to see if a combination of osteopromotive membranes of expanded polytetrafluoroethylene (e-PTFE; GORE-TEX®) and BMP, known to separately promote bone healing, would be stimulatory if combined. Bilateral transosseous ‘critical size’ defects at the mandibular angles in adult male rats were treated with either (i) various BMP preparations only; ii) lateral and medial coverage with e-PTFE membranes only; iii) a combination of various BMPs and membranes; or iv) left untreated. Two semi-purified bovine BMPs (bBMP), comprising collagen as carrier material, and recombinant human (rh) BMP-2 (1, 2 or 8 μg), delivered in either biodegradable beads of polylactide/polyglycolide acid (PLA/PGA) or purified collagen, were tested. After 12 or 24 days, block biopsies were taken for histological analysis. The different materials were well tolerated by the hosts and elicited large amounts of newly formed bone widely spread in the surrounding soft tissue. The combinations of bBMP and membranes did not improve the rate of bone healing compared to membranes only. In contrast, the combination of rhBMP-2 in PLA/PGA with membranes was more efficacious than membrane placement only and resulted in bone bridging at 24 days, with a bone contour resembling the original anatomy. The combination of membrane placement with rhBMP-2 may be of value in the clinic for bone regenerative purposes. The results are also of general importance for choosing carrier materials for delivery of other growth-stimulatory substances in combination with membranes.