首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
The purpose of this study was to compare the efficacy of tissue-engineered periosteum (TEP) to allgeneic bone in repairing segmental bone defect. TEP was fabricated with osteoinduced rabbit bone marrow mesenchymal stem cells (MSCs) and porcine small intestinal submucosa (SIS). Allogrfats were cryopreserved radial segments of New Zealand Rabbits. Forty-eight radial critical-sized defects (CSD) were bilaterally produced in 24 rabbits. The defects were divided into three groups, group A, TEP implantation, group B, SIS implantation, and group C allograft. Bone defect reconstruction was kinetically analyzed at 4, 8, and 12 weeks by radiographic and histological scoring system. In group A, bone defects were radiographically and histologically healed with mature cortex and marrow cavity by 12 weeks, while none of the defects healed in group B. Group C showed a slow process of creeping substitution with lymphocyte infiltration. Statistical comparison confirmed that group A had a more efficient and rapid bone defect reparation as well as remodelling than Group B and C. In conclusion, TEP is superior to structural allograft in reconstruction of allogenic segmental bone defect. Pure SIS cannot guide bone regeneration in this rabbit model.  相似文献   

2.
Tissue formation on scaffold outer edges after implantation may restrict cell infiltration and mass transfer to/from the scaffold center due to insufficient interconnectivity, leading to incidence of a necrotic core. Herein, a nano-hydroxyapatite/polyamide66 (n-HA/PA66) anisotropic scaffold with axially aligned channels was prepared with the aim to enhance pore interconnectivity. Bone tissue regeneration and infiltration inside of scaffold were assessed by rabbit cranial defect repair experiments. The amount of newly formed bone inside of anisotropic scaffold was much higher than isotropic scaffold, e.g., after 12 weeks, the new bone volume in the inner pores was greater in the anisotropic scaffolds (>50%) than the isotropic scaffolds (<30%). The results suggested that anisotropic scaffolds could accelerate the inducement of bone ingrowth into the inner pores in the non-load-bearing bone defects compared to isotropic scaffolds. Thus, anisotropic scaffolds hold promise for the application in bone tissue engineering.  相似文献   

3.
Repair of substantial cranial defects in adults and children may be compromised due to limitations in donor bone stocks for autologous grafts. We evaluated the capability of autologous adipose-derived mesenchymal cells (ADCs) in combination with polylactic acid (PLA) scaffolds to regenerate bone in a critical-sized skull defect. Thirty adult New Zealand White rabbits were divided into six groups of five animals each: (1) PLA alone (control), (2) fibronectin-coated PLA, (3) PLA with ADCs, (4) fibronectin-coated PLA with ADCs, (5) PLA with osteogenically induced ADCs (osADCs), and (6) fibronectin-coated PLA with osADCs. All the animals were humanely killed after 6 weeks. X-ray, histology, and histomorphometric analysis were performed to evaluate the new bone formation inside the PLA scaffold. Radiographically and histomorphometrically, the groups in which the PLA was not fibronectin coated showed no bone formation in contrast to the fibronectin-coated groups (Gp1 vs. Gp2, p < 0.0005); the group treated with osteo-induced ADCs and fibronectin (Gp6) showed significantly more bone formation than the group treated with undifferentiated ADCs (Gp4) and the group treated without cells (Gp5, p < 0.0005, in both cases). These data indicate that the surface treatment with fibronectin promotes bone formation within the scaffold, and that autologous, osteo-induced adipose-derived cells enhance bone formation if seeded into a fibronectin-treated PLA scaffold.  相似文献   

4.
Degradable polymer networks formed by the photoinitiated polymerization of multifunctional monomers have great potential as in situ forming materials, especially for bone tissue engineering. In this study, one specific chemistry was analyzed with respect to bone formation in a critical-sized defect model with and without adsorbed osteoinductive growth factors present. The scaffolds degraded in approximately 8 months and possessed an elastic modulus similar to that of trabecular bone. A porous scaffold fabricated with approximately 80% porosity and pore diameters ranging from 45 to 150 mm was implanted in a critical-sized cranial defect in rats. When implanted alone, the scaffolds were filled primarily with fibrous tissue after 9 weeks with only mild inflammation at the defect site. When the scaffolds released osteoinductive growth factors, statistically more bone filled the scaffold. For instance, 65.8+/-9.4% (n=5) of the defects were filled with radiopaque tissue in the osteoinductive releasing scaffolds, whereas only 24.2+/-7.4% (n=5) of the defects were filled in the untreated defects 9 weeks after implantation. These results illustrate not only the benefits of delivering osteoinductive factors when developing synthetic bone grafts, but the potential of these materials for supporting the infiltration and development of bone in large defects.  相似文献   

5.
The purpose of the present study was to observe the biodegradation process of pure alpha-tricalcium phosphate (alpha-TCP) particles and to determine the efficacy of alpha-TCP as a space maintainer in a bone defect. We used 14 rabbits and prepared two cranial bone defects in each rabbit. One defect was left empty as a control, whereas the other was filled with alpha-TCP particles about 300 mum in diameter. Animals were sacrificed at 1 week, 4 weeks, and 8 weeks. The cranial bone was then embedded either in paraffin wax for the preparation of decalcified specimens, or in polyester resin for the preparation of nondecalcified specimens. All specimens were evaluated histologically and histomorphometrically. As a consequence of the degradation of alpha-TCP, a "reticulate structure" appeared in the particles at 1 week and new bone was observed in this structure at 8 weeks. The amount of new bone between the control and experimental groups was not significantly different at any of the time points. However, in the experimental group, new bone at the surface of alpha-TCP was evident even in the center of the defect whereas fibrous connective tissue was dominant in the control group. These results indicate that alpha-TCP is a degradable osteoconductive material that is able to act as a space maintainer for bone regeneration when applied to a bone defect. While there was no significant difference in total bone formation between the experimental and negative control groups, the space-maintaining and osteoconductive properties of the particles may result in more complete bone formation in longer-term studies.  相似文献   

6.
Porous three-dimensional tyrosine-derived polycarbonate (TyrPC) scaffolds with a bimodal pore distribution were fabricated to mimic bone architecture using a combination of salt-leaching and phase separation techniques. TyrPC scaffolds degraded in register with bone regeneration during the 6-week study period and compressive moduli of the scaffolds were maintained >0.5 MPa at 6 weeks of incubation in PBS at 37 °C. The TyrPC scaffolds either unsupplemented or supplemented with recombinant human bone morphogenetic protein-2 (rhBMP-2) were implanted in a rabbit calvarial critical-sized defect (CSD) model and the TyrPC scaffolds treated with rhBMP-2 or TyrPC coated with calcium phosphate scaffold alone promoted bone regeneration in a rabbit calvarial CSD at 6 weeks postimplantation. A synthetic TyrPC polymeric scaffold either without a biological supplement or with a minimal dose of rhBMP-2 induced bone regeneration comparable to a commercially available bone graft substitute in a nonrodent CSD animal model.  相似文献   

7.
This study investigated the bone-regenerative potential of a demineralized bone and acellular matrix (DBM/AM) composite (AlloCraft DBM) in comparison with autologous bone using an in vivo model. Critical-sized calvarial defects (5 mm) were created in athymic rats. The defects were grafted with either the DBM/AM composite or the acellular human dermal matrix (AM), and compared with the defects filled with autologous bone (positive control) and the empty defect (negative control). Histological and radiographic assessments were carried out at 4 and 8 weeks after surgery to determine the biological healing, the amount and type of new bone formation and the percentage of new bone filled in the critical defects. At 4 weeks, DBM/AM composite group had the highest percentage of the defect filled with new bone (84%), which was significantly greater than autologous bone (62%), AM (41%), and untreated control (32%) groups. At 8 weeks, the DBM/AM continued to have the highest percentage of the defect filled with new bone (91%). The autologous bone group increased the percentage of bone fill to 83%. The defects either filled with AM or left untreated still had less of the defect filled with new bone, 57% and 33%, respectively. The total healing of defects grafted with DBM/AM was comparable with autologous bone group at 8 weeks. The results demonstrated that the DBM/AM composite promoted new bone formation more rapidly than autologous bone at calvarial defect in athymic rats. The study supports that DBM/AM is a potential substitute of autologous bone for bone repair.  相似文献   

8.
Recent studies suggest that human adipose tissue contains pluripotent stem cells, which are similar to bone marrow-derived stem cells. The objective of the present study was to assess the effect in bone regenerating capability of human adipose-derived stem cells (ADSCs) cultured in osteogenic media layered over poly lactide-co-glycolic acid (PLGA) and implanted in a critical nude rat calvarial defect. Twenty-seven nude rats were randomized into 3 groups (n = 9): 1) PLGA alone (control), 2) PLGA with undifferentiated ADSCs, and 3) PLGA with differentiated ADSCs. These 3 groups were divided into 9 subgroups (n = 3) according to in vitro pre-cultured periods (day 1 pre-culture (Group1), day 7 pre-culture (Group2), and day 14 pre-culture (Group3)) before implantation. An 8 mm critical-size circular calvarial defect was made in each nude rat. Specimens were harvested at 12 weeks post-implantation and evaluated radiographically and histologically. Radiodensitometric analysis revealed significantly higher bone growth in implants pre-cultured in osteogenic media for 14 days for Group 3. Histomorphometric analysis demonstrated that Groups 2 and 3 had bone formation filling 35% to 72% of the area of the defect after transplantation with cells that had been pre-cultured for 14 days. Constructs with differentiated ADSCs (Group 3) had noticeably more maximal and robust bone tissue regeneration than constructs with undifferentiated ADSCs (Group 2). These data provide evidence that constructs or implants made of PLGA and osteogenically differentiated ADSCs pre-cultured for 14 days before transplantation have better, more-robust bone regeneration capability in critical-sized skeletal defects than constructs with undifferentiated ADSCs. Human adipose derived stem cells can therefore be used as seed cells to construct tissue-engineered bone.  相似文献   

9.
目的 探讨不同月龄新西兰兔建立桡骨骨缺损模型时骨缺损大小的选择。方法 选取3月龄(幼龄兔)及6月龄(成年兔)健康雄性新西兰兔各20只,根据兔龄分为A组(3月龄)和B组(6月龄),每组兔前肢采用数字表法随机分为2亚组制备桡骨骨缺损模型,每组20侧。其中A1组、B1组桡骨骨缺损长度为15 mm,A2组、B2组骨缺损长度为20 mm。分别于模型制备术后第4、8、12周行X线检查,并应用X线Lane-Sandhu评分标准评估骨愈合情况。术后12周处死所有实验动物,取桡骨标本进行大体及组织学观察,分析骨愈合情况。结果 制备骨缺损模型术后,所有实验兔均存活。X线检查显示:术后第8周A1组骨缺损基本愈合,至第12周新生骨塑形完全,与正常桡骨形态类似;其余3组至第12周骨缺损均未完全修复,断端及邻近尺侧有少量新骨生成,髓腔封闭。术后各时间点X线Lane-Sandhu评分结果示:组内比较,A1组评分均高于A2组,差异均有统计学意义(P值均<0.05);B1组与B2组评分比较,差异均无统计学意义(P值均>0.05)。组间缺损尺寸相同的亚组间比较:A1组、A2组评分分别高于B1组、B2组,差异均有统计学意义(P值均<0.05)。术后12周标本大体观察显示:A1组断端形成骨性桥接,新生骨塑形良好,其余3组断端髓腔封闭,缺损区由纤维组织填充。组织学结果示A1组修复完全,新生骨骨板排列规则;其余3组缺损空腔可见纤维组织填充。结论 兔龄和骨缺损大小对于术后骨缺损愈合情况有重要影响,在构建兔桡骨骨缺损模型的动物实验中,幼龄兔(3月龄)骨缺损长度宜选择20 mm,成年兔(6月龄)宜选择15 mm。  相似文献   

10.
Immunologic Research - To compare human adipose tissue mesenchymal stem cells (AT-MSCs) and etanercept as immunomodulatory agents for collagen-induced arthritis (CIA). CIA was induced by...  相似文献   

11.
In neurosurgery, cranial incisions during craniotomy can be recovered by cranioplasty—a surgical operation using cranial implants to repair skull defects. However, surgeons often encounter difficulties when grafting prefabricated cranial plates into defective areas, since a perfect match to the cranial incision is difficult to achieve. Previous studies using mirroring technique, surface interpolation, or deformed template had limitations in skull reconstruction to match the patient’s original appearance. For this study, we utilized low-resolution and high-resolution computed tomography images from the patient to repair skull defects, whilst preserving the original shape. Since the accuracy of skull reconstruction was associated with the partial volume effects in the low-resolution images and the percentage of the skull defect in the high-resolution images, the low-resolution images with intact skull were resampled and thresholded followed by active contour model to suppress partial volume artifacts. The resulting low-resolution images were registered with the high-resolution ones, which exhibited different percentages of cranial defect, to extract the incised cranial part. Finally, mesh smoothing refined the three-dimensional model of the cranial defect. Simulation results indicate that the reconstruction was 93.94% accurate for a 20% skull material removal, and 97.76% accurate for 40% skull material removal. Experimental results demonstrate that the proposed algorithm effectively creates a customized implant, which can readily be used in cranioplasty.  相似文献   

12.
Human mesenchymal stem cells (hMSC) represent an attractive cell population for tissue engineering purposes. Furthermore, hMSC are described as immune privileged, and non-autogenous application seems possible. The current study examines the regeneration potential of hMSC after xenogenic transplantation compared with autogenous rabbit MSC in a critical-size bone defect. After isolation, hMSC and rabbit MSC were seeded on calcium-deficient hydroxyapatite (CDHA) and transplanted into a radial critical-size defect of New Zealand white rabbits. Defects were filled with a CDHA scaffold seeded with autogenous rabbit MSC, CDHA seeded with xenogenic hMSC or unseeded CDHA. An empty defect served as control group. Animals were sacrificed after 3 months. Evaluation was performed using radiography, micro-computed tomography (μ-CT) and histology. In addition, a non-destructive four-point-bending test was performed in order to evaluate biomechanical stiffness. While autogenous MSC seeded on CDHA led to increased healing of critical-size bone defects from radiological (μ-CT; p = 0.009) and histological (p = 0.048) perspectives compared with unloaded CDHA, it was not possible to demonstrate analogous effects for the xenogenic transplantation of hMSC. The xenogenic treatment group displayed inferior results in all parameters compared with the autogenous MSC treatment group (histology p = 0.041; μ-CT p = 0.006; biomechanical testing p = 0.017). Nevertheless, no local or systemic inflammatory response resulting from xenogenic transplantation was observed. While previous papers suggest the use of non-autogenous hMSC cells for tissue engineering purposes, the present results show inferior clinical results from transplantation of hMSC in a xenogenic setting compared with autogenous MSC.  相似文献   

13.
Clinically, allogeneic bone graft is used extensively because it avoids the donor site morbidity associated with autograft. However, there are concerns over the optimal sterilization method to eliminate immunological risks whilst maintaining the biological efficacy of the graft. This study compared the effect of Supercritical fluid (SCF) treatment and gamma irradiation at 25 kGy on the osteoconductivity of allograft bone in a bilateral critical sized defect rabbit model. Osteoconductivity was evaluated at 2 and 4 weeks using X-ray, CT, histology (qualitative and quantitative) and immunohistochemistry (Alkaline Phosphatase and Cathepsin-K). Both grafts were well tolerated and osteoconductive. At 2 weeks, there was decreased bone volume and density in the gamma irradiated graft compared to the SCF treated graft, corresponding with a greater inflammatory response histologically and increased Cathepsin-K expression. Catabolic activity predominated at 4 weeks, with both grafts undergoing significant resorption and remodeling inside the defect. Alkaline Phosphatase expression was greater in the SCF group at both time points indicative of a more anabolic response. Allograft bone sterilized with either gamma irradiation or SCF treatment was osteoconductive and capable of healing a critical sized tibial defect in a rabbit. Gamma irradiated allografts elicited an acute inflammatory reaction when implanted which may increase the amount of graft resorption compared to the SCF treated bone.  相似文献   

14.
This is the first reported study to prepare highly porous baghdadite (Ca3ZrSi2O9) scaffolds with and without surface modification and investigate their ability to repair critical-sized bone defects in a rabbit radius under normal load. The modification was carried out to improve the mechanical properties of the baghdadite scaffolds (particularly to address their brittleness) by coating their surfaces with a thin layer (~400 nm) of polycaprolactone (PCL)/bioactive glass nanoparticles (nBGs). The β-tricalcium phosphate/hydroxyapatite (TCP/HA) scaffolds with and without modification were used as the control groups. All of the tested scaffolds had an open and interconnected porous structure with a porosity of ~85% and average pore size of 500 μm. The scaffolds (six per scaffold type and size of 4 mm × 4 mm × 15 mm) were implanted (press-fit) into the rabbit radial segmental defects for 12 weeks. Micro-computed tomography and histological evaluations were used to determine bone ingrowth, bone quality, and implant integration after 12 weeks of healing. Extensive new bone formation with complete bridging of the radial defect was evident with the baghdadite scaffolds (modified/unmodified) at the periphery and in close proximity to the ceramics within the pores, in contrast to TCP/HA scaffolds (modified/unmodified), where bone tended to grow between the ulna adjacent to the implant edge. Although the modification of the baghdadite scaffolds significantly improved their mechanical properties, it did not show any significant effect on in vivo bone formation. Our findings suggest that baghdadite scaffolds with and without modification can serve as a potential material to repair critical sized bone defects.  相似文献   

15.
目的 探讨和观察中空羟基磷灰石复合rhBMP-2在骨缺损修复过程的再血管化。  方法 将48只成年的新西兰雄性大白兔制作成桡骨骨缺损模型,随机分3组,各组分别植入以下材料:中空HA/ rhBMP-2复合人工骨、单纯中空HA人工骨、单纯rhBMP-2。植入后于4、8、12、16周分别注射99mTc-MDP进行放射性核素骨显像并监测骨缺损修复过程中再血管化情况,同时进行大体、X线、组织学观察。  结果 术后各时间段,中空HA/ rhBMP-2复合人工骨组在X线及放射性核素聚集强度明显高于单纯中空HA人工骨组(P<0.05) ,表现为成骨代谢活跃及早期的再血管化能力。  结论 中空HA/ rhBMP-2复合人工骨具有良好的骨缺损修复能力,成骨活性持久,再血管化能力强,有望成为一种理想的骨缺损修复材料。  相似文献   

16.
背景:各种原因造成的骨折和骨缺损导致的骨不连一直是临床骨科修复的一大难题,相关产品质量的检验需要标准的骨缺损模型,然而骨缺损的临界长度至今仍无定论。 目的:建立兔桡骨骨缺损模型,以确定兔桡骨临界骨缺损长度。 方法:将18只雄性新西兰大白兔,随机分为6组,在双侧桡骨中段分别做12,13,14,15,16,17 mm的缺损,伤口缝合包扎但不固定。 结果与结论:大体标本和放射学观察显示,3个月内12,13,14,15,16 mm组的缺损均有修复完整的情况,但17 mm组无一例修复。组织学结果显示12,13,14,15,16 mm组缺损修复区有骨小梁与骨基质的形成、骨再生和再血管化、髓腔不同程度再通以及成骨细胞,17 mm组可见成骨细胞,破骨细胞,但未见骨再血管化和髓腔再通。故兔桡骨临界骨缺损长度为17 mm。  相似文献   

17.
The aim of this study was to develop an easily accessible and reproducible, nonhealing alveolar bone defect in the rabbit mandible. Twenty-four adult male New Zealand white rabbits underwent unilateral mandibular defect surgery. Two types of defect in the premolar/molar region were compared: (1) a 10-mm "full thickness" cylindrical defect removing both cortical plates and the intervening trabecular bone and tooth roots; (2) a 10-mm "partial thickness" cylindrical defect removing only the lateral bony cortex, trabecular bone, and tooth roots. Both types of defect were examined at 0, 8, and 16 weeks using histology and/or microcomputed tomography to determine the quality and quantity of bone formation. The partial thickness defect displayed significant bone fill at 8 weeks (86.9% +/- 10.8%), and complete regeneration of bony contours and bridging by 16 weeks. In contrast, the full thickness defect was never able to bridge itself and displayed no significant difference in bone regeneration between the 8-week (61.5% +/- 3.7%) and 16-week (55.1% +/- 18.5%) time points. These results indicate that a nonhealing defect can be created with a 10-mm bicortical cylindrical ostectomy placed in the premolar/molar region of the rabbit mandible, demonstrating the potential of this animal model as a test bed for mandibular biomaterials and tissue-engineering constructs.  相似文献   

18.
Beta-TCP bone graft substitutes in a bilateral rabbit tibial defect model   总被引:2,自引:0,他引:2  
The use of artificial bone graft substitutes has increased as the surgical applications widen and the availability of allograft bone decreases. The ideal graft substitute should reabsorb with time to allow and encourage new bone formation whilst maintaining its properties as an osteoconductive scaffold until it is no longer required. A potential disadvantage of some synthetic substitutes is their long dissolution time. Beta-tricalcium phosphates (beta-TCPs) have some advantages when compared to hydroxyapatite (HA), when used as a filler, in that it is more rapidly reabsorbed. Three commercially available and clinically used beta-TCP bone graft substitutes with the same chemistry (Vitoss, Osferion, Chronos) but with varying macro and microscopic characteristics were investigated using a bilateral tibial metaphyseal defect model in New Zealand white rabbits. When placed into tibial defects all three materials performed similarly in terms of mechanical properties of the healing defects. A decrease in properties was found at 12 weeks where implant resorption was nearly achieved while remodelling of the anteromedial cortex had yet to be completed. All materials were osteoconductive and supported new bone formation while implant resorption with time differed between materials. Vitoss resorbed faster than the other materials and is likely to differences in particle geometry, pore structure and interconnectivity.  相似文献   

19.
家兔和大鼠实验性动脉粥样硬化的比较研究   总被引:4,自引:0,他引:4  
谢作煊  李梅兰  何文芳 《解剖学研究》2000,22(2):98-100,T003
目的 研究在高脂血症的情况下影响动脉粥样硬化形成的有关因素。方法 用 10 %胆固醇脂肪乳剂复制大鼠和家兔的高脂血症模型 ,用生物化学、免疫组织化学和ELISA等技术检测血清中的脂蛋白、总胆固醇、TGF β1、2、3及其受体的表达 ;比较观察两种动物动脉粥样硬化形成的情况。结果 实验组家兔 10 0 %形成动脉粥样斑 (AS) ,血清高密度脂蛋白 (HDL)在正常范围 ;实验组大鼠未见动脉粥样斑形成 ,但其血高密度脂蛋白和TGF β随实验时间 (鼠龄 )的延长而升高。 结论 HDL有保护血管内皮细胞不被高脂血症损伤的作用 :TGF β仅在动脉内膜被高脂血症损伤后的炎症性增生反应过程中起作用。  相似文献   

20.
目的探讨辛伐他汀促进骨折愈合的效果。方法建立兔单侧桡骨骨折(3mm)模型36只,按照随机原则分为A、B、C3组,每组12只。A组为空白对照组,予以0.9%氯化钠溶液灌胃,骨折局部注射0.9%氯化钠溶液;B组为骨形态发生蛋白-2(BMP-2)对照组,予以0.9%氯化钠溶液灌胃,骨折局部注射BMP-2溶液;C组为辛伐他汀实验组,予以辛伐他汀配置液灌胃,骨折局部注射0.9%氯化钠溶液。在术后2、4、8周通过X射线摄片、病理组织切片、骨密度测定及生物力学测定(仅在第8周)等指标来观测评估骨折愈合情况,并分析各组骨折愈合程度差异有无统计学意义。结果 X射线摄片检查:在术后各个时间点,B组和C组在骨痂的形成改建及骨髓腔的再通上均要优于A组,而B、C两组间差异无统计学意义(P>0.05)。骨密度测定:术后2、4周时,C组、B组均优于A组,差异有统计学意义(P<0.05);且在第2周时B组要优于C组,差异有统计学意义(P<0.05);在第4周时,B组与C组差异无统计学意义(P>0.05)。在术后第8周时,A组要优于B组与C组,差异有统计学意义(P<0.05),而B组与C组差异无统计学意义(P>0.05)。生物力学测定(第8周时):B组和C组均高于A组,差异有统计学意义(P<0.05);B组和C组比较,差异无统计学意义(P>0.05)。组织形态学检查:C组和B组在胶原纤维、软骨组织、骨小梁及骨基质的形成时期均早于A组,B组和C组之间差异无统计学意义。结论辛伐他汀有良好的成骨作用;辛伐他汀可以促进骨折愈合,效果与BMP-2接近。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号