可控微结构电子束熔化成形钛合金支架作为成骨细胞载体修复兔骨缺损的研究

Objective To evaluate effects of titanium alloy scaffolds with controlled internal architecture as an osteoblast carrier on bone response in models of rabbit defects. Methods Electron beam melting process was utilized to fabricate porous titanium alloy scaffolds with fully interconnected and controlled internal pore architecture. After osteoblasts were seeded on the scaffolds and cultured for up to 7 days, the growth of rabbit osteoblasts on the scaffolds was observed by scanning electron microscopy. The experiment was conducted in 4 groups to evaluate the bone formation in vivo: group A (cell/scaffold composite), group B (scaffold only), group C (left empty) and group D (autogenous bone implant) . The scaffolds were transplanted into the rabbit defects after cultured in vitro for 7 days. The animals were sacrificed at 4, 8, and 12 weeks after implantation. Bone formation in the scaffolds was investigated by gross observation, histology and histomorphometry of non-decalcified sections and fluorochrome markers. Results Confluent cell layers could be observed on the scaffold surface and in the internal pores after 7 days of incubation in vitro. New bone growth and revascularization could be observed not only at the margins of the scaffolds, but also inside the central pores of the scaffolds after 12 weeks. New bone formed along the controlled internal channels of the scaffolds. The scaffolds were filled fully with the new bone tissue and blood vessels. More extensive new bone formation was found to originate from the host bone towards the implant in group A than in group B (P ＜0. 05) . Conclusions The controlled scaffolds are well biocompatible enough to accelerate healing of rabbit defects and new bone formation. The controlled honeycomb-like architecture may guide and promote the formation of mineralized tissue.     

可控微结构电子束熔化成形钛合金支架作为成骨细胞载体修复兔骨缺损的研究

Objective To evaluate effects of titanium alloy scaffolds with controlled internal architecture as an osteoblast carrier on bone response in models of rabbit defects. Methods Electron beam melting process was utilized to fabricate porous titanium alloy scaffolds with fully interconnected and controlled internal pore architecture. After osteoblasts were seeded on the scaffolds and cultured for up to 7 days, the growth of rabbit osteoblasts on the scaffolds was observed by scanning electron microscopy. The experiment was conducted in 4 groups to evaluate the bone formation in vivo: group A (cell/scaffold composite), group B (scaffold only), group C (left empty) and group D (autogenous bone implant) . The scaffolds were transplanted into the rabbit defects after cultured in vitro for 7 days. The animals were sacrificed at 4, 8, and 12 weeks after implantation. Bone formation in the scaffolds was investigated by gross observation, histology and histomorphometry of non-decalcified sections and fluorochrome markers. Results Confluent cell layers could be observed on the scaffold surface and in the internal pores after 7 days of incubation in vitro. New bone growth and revascularization could be observed not only at the margins of the scaffolds, but also inside the central pores of the scaffolds after 12 weeks. New bone formed along the controlled internal channels of the scaffolds. The scaffolds were filled fully with the new bone tissue and blood vessels. More extensive new bone formation was found to originate from the host bone towards the implant in group A than in group B (P ＜0. 05) . Conclusions The controlled scaffolds are well biocompatible enough to accelerate healing of rabbit defects and new bone formation. The controlled honeycomb-like architecture may guide and promote the formation of mineralized tissue.     

糖基化终末产物对人外周血内皮祖细胞生物学特性的影响

Objective In addition to be involved in the angiogenesis, endothelial progenitor cells (EPCs) have roles in endothelium repairing, wound healing, and for protecting blood vessels from restenosis, Advanced glycation end products (AGEs) facilitate the development and progression of atherosclerosis, diabetes associated vascular complications and uremia through various mechanisms such as damaging the endothelium, promoting leukocyte adhension, increasing the aggregation of platelets, and stimulating the proliferation of vascular smooth muscles. This study was designed to explore whether AGEs have effects on biological characteristics of EPCs in cultured human peripheral blood cells. Methods Total mononuclear cells (MNCs), isolated from human peripheral blood by density gradient centrifugatian and adherence cells filtration, were incuba-ted in fibronectin-coated culture dishes. Endothelial cells were identified by means of the adsorption of ulex eurepaeus-aggluti-nin- Ⅰ (UEA- Ⅰ) labelled with fluorescein isothiacyanate (FITC) and Dil-acLDL internalization. Four days later,various con-centrations of AGEs were added to the adherent cells and remained for48 hours. MTT assay and Boyden chamber were used for observing the proliferation and migration of EPCs. Human fibronectin was used to examine the adhesion ability of EPCs. Apop-tosis was induced in the EPCs with formaldehyde and Dnase Ⅰ as a positive control group. Annexin V-FITC/PI and TUNEL method of flow cytometry were used for evaluating the effects of AGEs on the rate of apeptosis in the EPCs. Results AGEs at high concentration decreased the number of EPCs independently (P < 0.01) ; reduced the proliferation (P < 0.01), migration (P<0.001) and adhesive capacity (P<0.05) of EPCs significantly,as well as increasing the apoptasis rate of EPCs in the early stage (P < 0.001). Conclusion AGEs may have adverse effects on EPCs from cultured human peripheral MNCs, such as decreasing their numbers and impairing their functions.     

Repair of the radial defect of rabbit with polyester/ tricalcium phosphate scaffolds prepared by rapid prototyping technology

Objective： To evaluate the effects of repairing rabbit radial defects with polyester/tricalcium phosphate scaffolds prepared by rapid prototyping technology loaded with bovine bone morphogenetic protein （ bBMP）, and find new carriers for growth factors. Methods： Polyester/tricalcium phosphate scaffolds prepared by rapid prototyping technology loaded with and without bovine BMP were used to repair the 15 mm radial defect in rabbit. Then the results of radiography, histology, scaffolds degrade rates and bone mineral density （BMD） were appraised to examine the effects at the 12th week. Results ： At the 12th week postoperatively, all defects treated with bBMP were radiographically repaired. No radius implanted polyester/tricalcium phosphate scaffolds without bBMP showed radiographic and histological union. At experimental groups, longitudinal alignment of lamellar structure was observed histologically at the 12th week,indicating that remodeling of regenerated bone was complete in different degree. Of the three experimental groups, the bony regeneration and remodeling of callus in poly lactide-co-glycolide/tricalcium phosphate （PLGA/ TCP） group was the best. The BMD values were beyond 70% of normal value at the 12th week while the PLGA/ TCP scaffolds group was the highest, and no abnormalities were observed in the surrounding soft tissue in all groups. Conclusions - Polyester/tricalcium phosphate scaffolds prepared by rapid prototyping technology loaded with bovine BMP can repair a 15 mm radial defect of rabbit. As for the results, the PLGA/TCP scaffold is ideal and better than poly L-lactide-co-D, L-lactide （ PDLLA/TCP ） scaffold, but the ploy L-lactic acid （PLLA/TCP） is not so good for its low degradation rates.     

急性胰腺炎时骨髓和循环内皮祖细胞的变化研究

Objective To investigate changes in number of endothelial progenitor cells(EPCs)from bone marrow and circulation in mice with acute pancreatitis.Methods BALB/c mice were assigned randomly to saline group and cerulein group.Animals were sacrificed at 12, 24 and 48 hours after injection.Bone marrow and circulating EPCs were detected by flow cyzometric analysis.Plasma VEGF, TNF-α and ET-1 were determined by enzyme-linked immunosorbent assay.The expression of VEGF in the pancreas was assessed by Western blotting.Apoptosis in situ was detected by TUNEL.Results The amounts of EPCs in bone marrow and circulation increased remarkably after cerulein injection(P < 0.05), also the levels of plasma VEGF TNF-α and ET-1(P < 0.05), the EPCs levels in bone marrow and circulation seen in the study closely mirrors the levels of VEGF detected in the circulation(r = 0.77, 0.67 individually).VEGF expression in pancreas was up-regulated after 12 h of cerulein injection compared with that of control group.Apoptosis of endothelial cells also increased in the cerulein group.Conclusion EPCs were mobilized by acute pancreatitis, which may be due to the mobilizing effect of increased levels of VEGF, EPCs may participate in the repair process of injured endothelium induced by acute pancreatitis.     

增强型生物活性玻璃-胶原复合支架材料的成骨效能研究

Objective To study the in vivo and vitro biocompatibility and osteogenetic capacity of enhanced bioactive glass/collagen composite scaffold. Methods Bone marrow stromal cells(BMSCs)were collected and induced to osteoblast-like cells.The growth rate of BMSCs was detected and compared progressively through Alamar Blue.The RNAs of the cells were collected and detected for bone morphogenetic protein-2(BMP-2),alkaline phosphatase(ALP),collagen Ⅰ(Col-Ⅰ)through qRT-PCR on the fourth and seventh days.Scaffolds with induced osteoblasts were embedded into 3 nude mice subcutaneously in vivo and detected after 6 weeks.X-ray,qRT-PCR and tissue staining were used to detect the mRNA expressions of BMP-2,Col Ⅰ,osteocalcin(OCN)and ostcopontin(OPN)and bone formation. Results SEM(scanning electronic microscopy)showed BMSCs attached to the scaffold tightly and viably and proliferated actively on the scaffold.The growth rate in the experimental group was significantly higher after 7 days(P<0.05)than in the control group.qRT-PCR showed that the mRNA expressions of BMP-2,ALP and Col-Ⅰ in the experimental group were significantly higher than in the control group on the seventh day(P<0.05).X-ray showed that the dense images of embedded scaffolds were locally similar to those of normal bone after 6 weeks.qRT-PCR showed that the mRNA expressions of BMP-2,Col Ⅰ,OCN and OPN in the experimental group were significantly higher than those of normal bone(P<0.05).HE and Massort staining of the paraffin sections showed the scaffolds degraded generally and osteoblasts and chondrocytes proliferated abundantly and distributed irregularly.Bone formation could be observed obviously. Conclusion Enhanced bioactive glass/collagen composite scaffolds have good biocompatibility and osteogenetic capacity in vitro and vivo.     

软骨细胞外基质源性取向支架与骨髓基质干细胞体外软骨组织工程的初步研究

Objective To fabricate cartilage extracellular matrix (ECM) oriented scaffolds and investigate the attachment, proliferation, distribution and orientation of bone marrow mesenchymal stem cells (BMSCs) cultured within the scaffolds in vitro. Methods Cartilage slices were shattered in sterile phosphate-buffered saline (PBS) and the suspension were differentially centrifugated untill the micro- fiber of the cartilage extracellular matrix was disassociated from the residue cartilage fragments. At last the supernatant were centrifugated, the precipitation were collected and were made into 2%-3% suspension. Using unidirectional solidification as a freezing process and freeze-dried method, the cartilage extracellular matrix derived oriented scaffolds was fabricated. The scaffolds were then cross-linked by exposure to ultraviolet radiation and immersion in a carbodiimide solution. By light microscope and scan electron microscope (SEM) observation, histological staining, and biomechanical test, the traits of scaffolds were studied. After being labelled with PKH26 fluorescent dye, rabbit BMSCs were seeded onto the scaffolds. The attachment, proliferation and differentiation of the cells were analyzed using inverted fluorescent microscope. Results The histological staining showed that toluidine blue, safranin O, alcian blue and anti-collagen Ⅱ immunohistochemistry staining of the scaffolds were positive. A perpendicular pore-channel structures which has a diameter of 100 μm were verified by light microscope and SEM analysis. The cell-free scaffolds showed the compression moduli were (2.02±0.02) MPa in the mechanical testing. Inverted fluorescent microscope showed that most of the cells attached to the scaffold. Cells were found to be widely distributed within the scaffold, which acted as a columnar arrangement. The formation of a surface cells layer was found on the surface of the scaffolds which resembled natural cartilage. Coclusion The cartilage extracellular matrix derived oriented scaffolds have promising biological, structural, and mechanical properties.     

顺铂联合加热对体外血液中肝肿瘤细胞的杀灭作用及对红细胞的影响

Objective To investigate the effectiveness of cis-diamminedichloroplatinum (DDP) combined with hyperthennia in killing liver tumor cells and its influence on erythrocytes in vitro. Methods Cultured liver tumor cells (2 ml) were mixed with erythrocyte suspension (10 ml) and then the mixture was separated into 6 centrifuge tubes with 2 ml in each one. The centrifuge tubes were randomly divided into A-F groups and the experiment was repeated for 30 times. Normal saline 2 ml was added in A and D groups. DDP 2 ml (200 μg/ml) was added in B and E groups. DDP 2 ml (400 μg/ml) was added in C and F groups. The cells were then incubated in warm bath of 37 ℃ for 30 min in A, B and C groups and in warm bath of 42 ℃ for 30 min in the other three groups.After hyperthermic treatment, tumor cells were isolated from erythrocytes using density gradient centrifugation, the inhibition rate of tumor cells was determined by MTT method and the clone formation of tumor cells was checked.The erythrocyte osmotic fragility and content of 2,3-diphosphoglyceric acid in erythrocytes were measured. Results The inhibition rate of tumor cells was gradually increased, while the rate of tumor cell clone formation decreased with the increase in the temperature and DDP concentrations ( P < 0.01) . The rate of tumor cell clone formation was more than 98% and no clone formation was tested in group F. There was no significant difference in the content of 2,3-diphosphoglyceric acid in erythrocytes between before and after hyperthermic treatment in group F ( P >0.05 ) . The rate of hemolysis of erythrocytes was less than 1 % in the 0.68 % sodium chloride solution in group F.Conclusion DDP 200 μg/ml combined with hyperthermic treatment with temperature of 42 ℃ for 30 min can make the liver tumor cells lose the capability of proliferation, however, it exerts slight effect on erythrocyte membrane and no influence on the oxygen-carrying capacity of erythrocytes.     

顺铂联合加热对体外血液中肝肿瘤细胞的杀灭作用及对红细胞的影响

Objective To investigate the effectiveness of cis-diamminedichloroplatinum (DDP) combined with hyperthennia in killing liver tumor cells and its influence on erythrocytes in vitro. Methods Cultured liver tumor cells (2 ml) were mixed with erythrocyte suspension (10 ml) and then the mixture was separated into 6 centrifuge tubes with 2 ml in each one. The centrifuge tubes were randomly divided into A-F groups and the experiment was repeated for 30 times. Normal saline 2 ml was added in A and D groups. DDP 2 ml (200 μg/ml) was added in B and E groups. DDP 2 ml (400 μg/ml) was added in C and F groups. The cells were then incubated in warm bath of 37 ℃ for 30 min in A, B and C groups and in warm bath of 42 ℃ for 30 min in the other three groups.After hyperthermic treatment, tumor cells were isolated from erythrocytes using density gradient centrifugation, the inhibition rate of tumor cells was determined by MTT method and the clone formation of tumor cells was checked.The erythrocyte osmotic fragility and content of 2,3-diphosphoglyceric acid in erythrocytes were measured. Results The inhibition rate of tumor cells was gradually increased, while the rate of tumor cell clone formation decreased with the increase in the temperature and DDP concentrations ( P < 0.01) . The rate of tumor cell clone formation was more than 98% and no clone formation was tested in group F. There was no significant difference in the content of 2,3-diphosphoglyceric acid in erythrocytes between before and after hyperthermic treatment in group F ( P >0.05 ) . The rate of hemolysis of erythrocytes was less than 1 % in the 0.68 % sodium chloride solution in group F.Conclusion DDP 200 μg/ml combined with hyperthermic treatment with temperature of 42 ℃ for 30 min can make the liver tumor cells lose the capability of proliferation, however, it exerts slight effect on erythrocyte membrane and no influence on the oxygen-carrying capacity of erythrocytes.     

Bone regeneration with osteogenic matrix cell sheet and tricalcium phosphate:An experimental study in sheep

AIM To determine the effects of a cell sheet created from sheep bone marrow and tricalcium phosphate(TCP) on osteogenesis.METHODS Bone marrow cells were harvested from a sheep and cultured in a minimal essential medium(MEM) containing ascorbic acid phosphate(AscP) and dexamethasone(Dex). After 2 wk, the formed osteogenic matrix cell sheet was lifted from the culture dish using a scraper. Additionally, harvested bone marrow cells were cultured in MEM only as a negative control group, and in MEM with AscP, Dex, and β-glycerophosphate as a positive control group. For in vitro evaluation, we measured the alkaline phosphatase(ALP) activity and osteocalcin(OC) content in the media of the cultured cells from each group. For in vivo analysis, a porous TCP ceramic was used as a scaffold. We prepared an experimental group comprising TCP scaffolds wrapped with the osteogenic matrix cell sheets and a control group consisting of the TCP scaffold only. The constructs wereimplanted subcutaneously into athymic rats and the cell donor sheep, and bone formation was confirmed by histology after 4 wk.RESULTS In the in vitro part, the mean ALP activity was 0.39 ± 0.03 mg/well in the negative control group, 0.67 ± 0.04 mg/well in the sheet group, and 0.65 ± 0.07 mg/well in the positive control group. The mean OC levels were 1.46 ± 0.33 ng/well in the negative control group, 3.92 ± 0.16 ng/well in the sheet group, and 4.4 ± 0.47 ng/well in the positive control group, respectively. The ALP activity and OC levels were significantly higher in the cell sheet and positive control groups than in the negative control group(P 0.05). There was no significant difference in ALP activity or OC levels between the cell sheet group and the positive control group(P 0.05). TCP constructs wrapped with cell sheets prior to implantation showed bone formation, in contrast to TCP scaffolds alone, which exhibited poor bone formation when implanted, in the subcutaneous layer both in athymic rats and in the sheep. CONCLUSION This technique for preparing highly osteoinductive TCP may promote regeneration in large bone defects.     

复合血管内皮祖细胞的组织工程骨在修复大段骨缺损实验中的血管化评价

目的 评价复合了血管内皮祖细胞(EPCs)的组织工程骨在修复兔桡骨大段骨缺损实验中的血管化情况.方法 自体骨髓通过不同方法的体外培养,获得EPCs及经成骨诱导的骨髓基质干细胞(BMSCs),与脱钙骨基质(DBM)构建组织工程骨修复兔桡骨大段骨缺损.用墨汁灌注、放射性核素骨显像、血管内皮细胞生长因子和Ⅷ因子相关抗原的免疫组化方法观察术后不同时期实验组(EPCs+BMSCs+DBM)、自身对照组(BMSCs+DBM)、阴性对照组(DBM)的骨组织血管化情况.结果 各组手术后2周骨缺损区新生血管数量增加,血流量开始升高,4周和8周时达到峰值,12周后开始下降.实验绀的新生血管数量和局部血流量在术后2、4、8周明显高于自身对照组和阴性对照组,血管排列更整齐.结论 复合EPCs的组织工程骨在修复大段骨缺损时,能促进早期血管化,从而进一步促进成骨.     

促进内皮祖细胞生长的细胞外基质组织工程血管支架的研究

目的 研究鼠骨髓来源内皮祖细胞(endothelial progenitor cells,EPCs)在不同类型细胞外基质支架上的生长特性,为EPCs生长寻找新的生物组织工程血管支架.方法 EPCs种植于细胞外基质支架(extracellular matrix,ECM)上.培养不同时间点用免疫荧光技术鉴定并细胞记数;电镜观察支架表面结构及EPCs的生长情况;Western blotting法、real-time PCR法检测VWF(von Willebrand factor)蛋白及mRNA表达变化.结果 在1、3、5 h 3个检测点的压缩组细胞贴壁率明显高于未压缩组(P<0.01).在1、3、7 d压缩组的细胞数明显高于未压缩组(P<0.05),10d后差异无统计学意义,且压缩组细胞形态较成熟,与内皮细胞相似,有一个较平整的细胞平面.Western blotting检测表明3、7、10 d VWF蛋白在压缩支架上表达比未压缩支架上强,14 d后两组表达相当.real-time PCR结果示3、7、10 d压缩组VWF基因表达量明显高于未压缩组(P<0.01),14 d后两组表达无差异.结论 压缩ECM更能促进EPCs黏附、增殖和分化,可作为一种新的合成人工血管的生物组织工程支架.     

人脐血间充质干细胞修复颅骨缺损的实验研究

目的 应用人脐血间充质干细胞(umbilical cord blood derived mesenchymal stem cells,UCB-MSCs)复合脱钙骨材料构建组织工程化骨,修复裸大鼠颅骨标准缺损.方法 体外扩增培养、成骨诱导人UCB-MSCs,采用Alizarin Red染色和钙离子半定量的方法测定细胞成骨分化能力.将第2代细胞接种在脱钙骨支架材料上继续诱导培养,扫描电镜检测细胞在材料上的生长状况.制备裸大鼠双侧颅骨全层标准缺损(直径5 mm),一侧以细胞材料复合物修复作为实验侧(n=8);另一侧以单纯脱钙骨材料修复作为对照侧(n=8).术后6、12周取材,分别通过大体形态观察、显微CT(Micro-CT)、组织学方法检测颅骨缺损的修复效果.结果 UCB-MSCs体外能够诱导分化为成骨细胞,且在脱钙骨支架材料上生长良好.Micro-CT检测显示术后6周实验侧有部分新生骨组织形成,12周时骨缺损修复率达(78.19±6.45)%,脱钙骨材料降解完全;对照侧6周时无明显新骨生成,12周时材料完全降解,骨缺损未修复.组织学检测显示12周时实验侧有较多成熟骨生成,为骨性愈合;对照侧骨缺损为纤维愈合.结论 成骨诱导的人UCB.MSCs复合脱钙骨材料构建的组织工程化骨可修复裸大鼠颅骨全层标准缺损,有望成为新的组织工程骨种子细胞来源.     

Evaluation of Partially Demineralized Osteoporotic Cancellous Bone Matrix Combined with Human Bone Marrow Stromal Cells for Tissue Engineering: An In Vitro and In Vivo Study

Allogenous demineralized bone matrix (DBM) represents a potential scaffold for bone tissue engineering due to its close relation in structure and function with autologous bone, but its supply is often restricted by donor availability. Thus, an expanded source of human bone is needed. The aim of this study was to evaluate the capacity of partially DBM scaffolds derived from allogenous cancellous bone of osteoporotic femurs to support osteogenesis of human bone marrow stromal cells (BMSCs) in vitro and in vivo in order to assess their potential use in bone tissue-engineering strategies. Human BMSCs of passage 2 were seeded either on osteoporotic bone–derived DBM scaffolds or on normal bone–derived scaffolds and cultured in osteogenic medium for 14 days. To assess the in vitro proliferation potential and osteogenic differentiation of BMSCs on scaffolds, scanning electronic microscopy observation, DNA content assays, and measurements of alkaline phosphatase activity and osteocalcin content were applied; the results displayed no significant differences between the osteoporotic DBM group and the normal DBM group. After 2 weeks of subculture in vitro, the BMSC/DBM composites were subcutaneously implanted into athymic mice for 8 weeks to evaluate their in vivo bone-forming ability. Histological examination showed tissue-engineered bone formation in the DBM pores in both groups, and no significant differences were observed in either the extent or frequency of new bone formation between these two groups. Based on these results, it can be concluded that osteoporotic bone–derived DBM may serve as a promising scaffold for bone tissue engineering.     

同种异体脂肪干细胞复合脱钙骨修复大鼠尺骨缺损

目的探讨同种异体脂肪干细胞修复管状骨缺损的可行性。方法获取SD大鼠的腹股沟处脂肪,分离培养脂肪干细胞（Adipose-Derived Stem Cells,ADSCs）;鼠第3代ADSCs与脱钙骨复合,24 h后进行成骨诱导培养。检测细胞在材料表面的生长及成骨分化能力。建立鼠两侧尺骨缺损模型,分别植入鼠ADSCs-脱钙骨复合物（实验侧）和单纯脱钙骨材料（对照侧）;8周、24周后取样,行DR和组织学检测,观察成骨情况。结果 ADSCs能在脱钙骨上很好地黏附和生长,并维持成骨分化能力。细胞-材料复合物植入24周后,DR显示实验侧有新生骨基质长成,对照侧未见骨组织生成。组织学检测显示,实验侧缺损区被典型的骨组织取代,可见新生骨小梁附着于脱钙骨表面;对照侧只有少量的骨组织和纤维组织充填。结论 ADSCs-脱钙骨材料复合物植入,能成功修复临界大小的管状骨缺损。     

可控微结构电子束熔化成形钛合金支架作为成骨细胞载体修复兔骨缺损的研究

目的 探讨可控微结构电子束熔化成形钛合金支架作为成骨细胞载体修复兔骨缺损的可行性.方法 应用电子束熔化成形技术制备支架,将成骨细胞与支架复合培养7 d后,通过扫描电镜观察细胞与材料复合情况.将培养7 d的支架/细胞复合物及单纯支架植入兔体内.72只雄性新西兰白兔均制作骨膜-骨缺损模型后随机分为4组(n=18):A组缺损处植入细胞/支架复合物,B组缺损处植入单纯支架,C组缺损处旷置,D组缺损处置入自体骨.分别在第4、8、12周取材,行大体观察、四环素荧光标记、组织学观察以及新生骨定量分析等评价新骨形成及缺损愈合情况.结果 支架与细胞体外共培养7 d后,支架表面及内部孔隙有大量细胞黏附并与材料牢固结合.第12周,新生骨组织和血管不仅在支架周围有生长,而且沿着支架的管道结构向支架内部生长并逐渐填满支架内部,新生骨组织与支架牢固结合并形成一个相互嵌合的复合体.新生骨定量分析显示:第4周,各组间两两比较,差异均无统计学意义(P＞0.05).第8周,A组分别与B、C组比较,差异均有统计学意义(P＜0.05);D组分别与B、C组比较,差异均有统计学意义(P＜0.05).第12周,组间两两比较,差异均有统计学意义(P＜0.05).结论 可控微结构电子束熔化成形钛合金支架具有良好的生物相容性,能够促进支架内新骨生成及缺损的愈合.     

脂肪干细胞及血管束植入法联合应用对组织工程支架体内血管化的影响

目的探讨脂肪十细胞(adipose-derived stem cells,ADSCs)及血管束植入法联合应用对组织工程支架体内血管化的影响,为临床应用组织工程支架复合物治疗股骨头缺血性坏死提供理论依据。方法取4月龄SD大鼠,分离培养ADSCs,并行成骨诱导鉴定。取第3代ADSCs接种于纳米羟基磷灰石/聚酰胺66(nano-hydroxyapatide/polyamide-66,nHA/PA66)支架上制备复合支架,扫描电镜观察细胞与支架复合情况。取4月龄SD大鼠24只,体重350～400 g,随机分为3组,每组8只。A、B组分离大鼠双侧腹壁下动、静脉,分别将血管束植入培养10 d的复合支架及单纯nHA/PA66支架;C组将培养10 d的复合支架包埋入双侧股四头肌中。术后2、4周每组取4只大鼠支架标本行HE染色及CD34免疫组织化学染色观察,检测其血管生成情况。结果所分离细胞经鉴定为ADSCs。扫描电镜观察示复合培养10d,细胞数目增多,形态完全伸展,呈长梭形。术后2、4周,HE染色及免疫组织化学染色均显示A组支架植入动、静脉周围有大最血管生成,血管数量及管壁成熟度均优于同一时间点的B、C组。术后2、4周,A组血管密度和血管直径均显著大于B、C组,B组大于C组,差异均有统计学意义(P<0.05)。结论 ADSCs和血管束植入法联合应用可以促进组织工程支架体内血管化程度。     

Bone Morphogenetic Protein-6-loaded Chitosan Scaffolds Enhance the Osteoblastic Characteristics of MC3T3-E1 Cells

The purpose of this study is to investigate the convenience of bone morphogenetic protein-6 (BMP-6)-loaded chitosan scaffolds with preosteoblastic cells for bone tissue engineering. MC3T3-E1 cells were seeded into three different groups: chitosan scaffolds, BMP-6-loaded chitosan scaffolds, and chitosan scaffolds with free BMP-6 in culture medium. Tissue-engineered constructs were characterized by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazoliumbromide assay, scanning electron microscopy (SEM), mineralization assay (von Kossa), alkaline phosphatase (ALP) activity, and osteocalcin (OCN) assays. BMP-6-loaded chitosan scaffolds supported proliferation of the MC3T3-E1 mouse osteogenic cells in a similar pattern as the unloaded chitosan scaffolds group and as the chitosan scaffolds with free BMP-6 group. SEM images of the cell-seeded scaffolds revealed significant acceleration of extracellular matrix synthesis in BMP-6-loaded chitosan scaffolds. Both levels of ALP and OCN were higher in BMP-6-loaded chitosan scaffold group compared with the other two groups. In addition, BMP-6-loaded scaffolds showed strong staining in mineralization assays. These findings suggest that BMP-6-loaded chitosan scaffold supports cellular functions of the osteoblastic cells; therefore, this scaffold is considered as a new promising vehicle for bone tissue engineering applications.     

壳聚糖与重组人骨形成蛋白2复合物体外成骨作用的研究

目的探讨复合重组人骨形成蛋白2(recombinanthumanbonemorphogeneticprotein2,rhBMP-2)的壳聚糖-明胶支架的体外成骨作用。方法将rhBMP-2与壳聚糖-明胶支架复合,按2×104/ml的密度接种成骨细胞系或成肌细胞系至rhBMP-2复合材料上,以及无rhBMP-2复合的对照材料上。A组(2T3成骨细胞接种组),其中实验A组复合有rhBMP-2的材料14块,分别于接种培养第3、7、14和21天各取3块,以管家基因β-tubulin为内参照,RT-PCR行半定量分析,测定骨钙素基因表达水平,余2块于第14天终止培养,茜素红-S染色观察钙盐沉积情况;对照A组未复合rhBMP-2的材料5块,接种培养至14d终止,其中3块用于测定骨钙素基因表达,2块测定钙盐沉积。B组(C2C12成肌细胞接种组),实验组及对照组情况、培养时间及检测指标同A组。另取接种有rhBMP-2的材料2块接种2T3成骨细胞,培养3d后扫描电镜观察细胞与材料的黏附情况。结果A组培养3d,扫描电镜可见成骨细胞紧密黏附于多孔材料网表面,生长状态良好。实验A组成骨细胞中骨钙素基因的表达为1.28±0.17,对照A组14d为0.56±0.09,表明复合rhBMP-2可促进材料中骨钙素基因表达,两者差异有统计学意义(P<0.01);rhBMP-2还可诱导不表达骨钙素基因的C2C12成肌细胞出现基因表达,B组培养21d,实验B组为0.58±0.13,对照B组为0,差异有统计学意义(P<0.01)。茜素红-S染色可见,A组材料网络内均有不同程度的钙盐沉积。接种相同的细胞时,复合有rhBMP-2的材料中有更多的钙盐沉积。结论复合有rhBMP-2的壳聚糖-明胶人工骨支架材料在体外具有良好的诱导成骨能力。     

玉米醇溶蛋白仿生组织工程支架材料体内外诱导成骨的实验研究

目的 检测玉米醇溶蛋白(zein)仿生三维多孔支架材料的生物相容性、骨诱导性和生物可降解性. 方法 将人骨髓基质干细胞(BMSCs)载人海藻酸钠或zein制成复合物.通过扫描电镜观察、噻唑蓝分析法以及碱性磷酸酶染色与定量检测,分别比较zein和海藻酸钠对BMSCs体外黏附、增殖和分化的影响.取24只8周龄裸鼠,随机分为两组,制成肌袋植入异位成骨模型.对照组单纯植入zein,实验组植入zein与兔BMSCs复合物.术后2、4、8和12周取材进行影像学和组织学观察. 结果 与海藻酸钠相比,zein在任何时间段均能够更好地促进兔BMSCs的体外增殖和分化,差异有统计学意义(P<0.05).同时,与单纯植入zein相比,BMSCs能够增强zein体内诱导成骨的作用. 结论 zein具有良好的生物相容性、骨诱导性和生物可降解性.