唑来膦酸、聚乳酸-羟基乙酸聚合物、β-磷酸三钙复合支架修复去势大鼠股骨干骺端骨缺损的实验研究

目的唑来膦酸、聚乳酸-羟基乙酸聚合物、β-磷酸三钙(ZA、PLGA、β-TCP)复合支架对去势大鼠股骨干骺端骨缺损的修复作用。方法雌性SD大鼠经过双侧去卵巢手术后饲养3个月建立骨质疏松模型,随后在大鼠双侧股骨干骺端建立直径为3 mm圆形骨缺损,上述大鼠随机分为4组;分别置入ZA、PLGA支架,β-TCP支架和ZA、PLGA、β-TCP复合支架,不置入支架材料的为对照组。术后12周取材,通过Micro-CT扫描重建和病理组织学评价三组支架材料的成骨作用。结果术后观察发现空白对照组骨缺损未修复,骨缺损断端硬化,而其他3组骨缺损均有不同程度修复。植入骨质疏松大鼠体内12周后,三组材料随着材料的降解均有新生骨长入,且三组新骨生成率均显著优于对照组(P0.05),缺损区域都有较高BV/TV、Tb.Th、Tb.N、Conn.D、骨矿化沉积率(MAR)和较低的Tb.Sp,其中以ZA、PLGA、β-TCP组最高。Micro-CT和病理组织学结果提示ZA、PLGA、β-TCP组骨修复效果较ZA、PLGA与β-TCP组更好。结论 ZA、PLGA、β-TCP复合支架具有明显促进去势大鼠股骨干骺端骨缺损修复的作用。     

多孔载因子CPC促进骨缺损愈合的实验研究

[目的]探讨磷酸钙骨水泥复合rhBMP-2/明胶微球复合材料在治疗骨缺损时的降解、成骨性能。[方法]制备携载rhBMP-2的明胶微球(GMs),与磷酸钙骨水泥(CPC)复合,制备出rhBMP-2/GMs/CPC复合人工骨。取30只新西兰大白兔,在前臂桡骨中段制造人工骨缺损,随机分成3组,分别植入rhBMP-2/GMs/CPC/复合物(A组)、GMs/CPC(B组)、rhBMP-2/CPC(C组),术后6、12周分别进行X线检测、骨密度测定,术后12周处死动物,分别行生物力学测定,脱钙切片、HE染色,不脱钙切片进行荧光显微镜下观察双标间距,计算平均矿化率。[结果]与GMs/CPC、rhBMP-2/CPC组比较,复合材料植入后不同时间点的材料降解及成骨均高于对照组。12周A组标本生物力学实验测定结果表明指标接近正常,与B、C组比较有统计学差异。骨密度12周、新骨矿化率提示有统计学差异。[结论]rhBMP-2/GMs/CPC微球系统复合材料在体内易降解,具有良好成骨活性,是良好的骨修复材料。     

干细胞复合Ⅰ型胶原修饰的PLGA微球治疗骨质疏松性骨缺损

 目的 观察骨髓间质干细胞复合Ⅰ型胶原修饰的聚乳酸聚乙醇酸(PLGA)微球支架注入骨质疏松大鼠股骨转子间骨缺损后骨质量的局部改善情况。方法 制备Ⅰ型胶原修饰的PLGA微球支架,将干细胞与该支架共同培养。40 只3月龄雌性SD大鼠去势建立骨质疏松模型,随机分为对照组、缓冲液组、细胞组、微球组、细胞+微球组,每组8只,于股骨转子间用电钻制作骨缺损,每侧注入不同材料约30 μl。术后1个月和3个月每组各处死4只大鼠,取股骨标本用骨密度仪和Micro CT测定转子间骨密度、骨小梁结构。结果 骨髓间质干细胞与Ⅰ型胶原修饰的PLGA微球支架体外培养7d, 扫描电镜发现细胞在支架表面黏附、增殖良好。将不同材料分别植入大鼠骨缺损部位,术后1个月,各组转子间骨矿含量及骨密度比较,差异均无统计学意义。细胞+微球组骨小梁厚度高于缓冲液组和微球组,骨小梁面积百分数高于细胞组和 微球组,骨小梁分离度与对照组、缓冲液组和微球组相比有减少趋势,但差异无统计学意义。术后3个月,细胞+微球组转 子间骨矿含量有高于缓冲液组和微球组的趋势,但差异无统计学意义;BMD高于对照组、缓冲液组、细胞组和微球组;骨小梁厚度高于对照组、缓冲液组、微球组和细胞组,骨小梁面积百分数高于对照组和缓冲液组,骨小梁分离度与对照组、缓冲液组、细胞组和微球组相比有减少趋势,但差异无统计学意义。结论 骨质疏松部位植入干细胞复合Ⅰ型胶原修饰的 PLGA微球1个月,即可修复骨质疏松部位骨缺损;3个月,可改建骨质疏松部位骨小梁结构,提高骨质量。     

万古霉素阳离子脂质体复合纳米羟基磷灰石/壳聚糖/魔芋葡甘聚糖治疗兔慢性感染性骨缺损

目的检验阳离子脂质体包封万古霉素复合纳米羟基磷灰石/壳聚糖/魔芋葡甘聚糖(nanohydroxyapatite/chitosan/koniac glucomannan,n-HA/CS/KGM)支架体内抗感染及骨修复活性。方法取6月龄健康新西兰大白兔51只,体重1.5～3.0kg,用金黄色葡萄球菌制备慢性感染性双侧胫骨骨缺损模型。将造模后4周存活的48只兔随机分为4组,每组12只。根据以下分组方法,分别于双侧骨缺损处植入相应支架。A组;清创后不作任何处理;B组:n-HA/CS/KGM空白支架组;C组:万古霉素复合n-HA/CS/KGM支架组;D组:万古霉素阳离子脂质体复合n-HA/CS/KGM支架组。治疗后8周行大体、骨缺损修复、组织学观察以及X线片、细菌学检查。结果实验动物造模后4周X线片显示明显骨质缺损、低密度影及软组织肿胀影,Norden评分均>3分,为(3.83±0.52)分。治疗后8周大体观察:C、D组窦道已愈合,A、B组仍有窦道;大体观察病理评分C、D组明显优于A、B组(P<0.05)。骨缺损修复观察:D组骨缺损已修复,骨缺损最长径显著优于A、B、C组(P<0.05)。X线片检查:C、D组可见新骨形成,A、B组可见骨膜反应及髓腔低密度影;Norden评分D组明显小于A、B、C组(P<0.05)。组织学观察:HE染色示C、D组可见大量骨小梁形成,纤维增生,未见明显感染迹象,A、B组仍可见中性粒细胞积聚;Smeltzer评分C、D组明显优于A、B组(P<0.05)。细菌学检查:C、D组阴性率明显高于A、B组(P<0.05)。结论万古霉素阳离子脂质体复合n-HA/CS/KGM支架可很好治疗兔慢性感染性胫骨骨缺损,为临床上治疗慢性感染性骨缺损提供了新思路。     

壳聚糖/羟基磷灰石支架修复骨软骨缺损的实验研究

[目的] 探讨双层壳聚糖(chitosan CS)/羟基磷灰石复合支架(hydroxyapatite HA)修复兔骨软骨缺损的可行性.[方法] 采用冻干法和烧结法制作双层壳聚糖(CS)/羟基磷灰石(HA)复合支架,以骨髓间充质干细胞为种子细胞,运用纤维蛋白胶种植技术,以双层壳聚糖(CS)/羟基磷灰石(HA)复合支架为载体,修复骨软骨缺损,实验分3组,A组:BMSc 支架,B组:单纯支架,C组:未处理.将修复材料植入骨软骨缺损模型,分别于6、12周取材,进行大体观察,组织学检测,改良Wakitani法评分,经统计学处理,比较各组修复效果差异(P＜0.05).[结果] (1)CS/HA支架CS层孔隙率为76%± 5.01%,孔径为200～400 μm,平均为300 μm左右,孔相通性好,HA层孔隙率为72%± 4.23%,孔径为200～500 μm,平均为350 μm左右,孔相通性好,结合部结合好;(2)P2骨髓间充质干细胞较纯,扫描电镜观察MSCs附着在复合支架上.大体观察和组织学检测显示, A组基本修复软骨缺损,骨缺损有骨小梁长入.B、C组骨软骨缺损修复不良,组织学检测以纤维性组织或无新生组织形成,软骨及骨缺损均明显存在,改良Wakitani评分显示A组在6周、12周2个时间点的各项评分结果,均优于B、C组,且差异有统计学意义(P＜0.05).[结论] 双层壳聚糖(CS)/羟基磷灰石(HA)复合支架可作为骨软骨组织工程支架,结合BMSc可修复软骨与骨的缺损,重建关节的解剖结构和功能.     

3D打印聚乳酸-羟基乙酸共聚物数字化仿生组织工程骨支架修复兔股骨干长节段骨缺损研究

目的:探讨3D打印聚乳酸-羟基乙酸共聚物(PLGA)数字化仿生组织工程骨支架对兔股骨干长节段骨缺损的修复效果。方法:取19只新西兰大白兔,1只用于3D打印PLGA数字化仿生组织工程骨支架制备,18只制备股骨干长节段骨缺损模型,分为自体骨移植组(A组)、传统支架组(B组)、组织工程骨支架组(C组)各6只。在术后4、8、1...     

微载体/水凝胶复合支架修复大鼠膝关节骨软骨缺损

[目的]探索以负载软骨细胞的Cytodex-3微载体和藻酸钠水凝胶为材料,制备微载体/水凝胶复合支架,并观察以此修复大鼠膝关节骨软骨缺损的效果。[方法]将大鼠软骨细胞与Cytodex-3微载体置于旋转式三维生物反应器(rotary cell culture systems,RCCS)中,软骨细胞在微载体表面快速大量扩增后,将负载有软骨细胞的微载体均匀的与藻酸钠水凝胶混合,制备微载体/水凝胶复合支架,并以此修复大鼠股骨滑车骨软骨缺损。实验分3组,A组:负载有软骨细胞的Cytodex-3微载体/藻酸钠水凝胶复合支架修复组;B组:单纯Cytodex-3微载体/藻酸钠水凝胶复合支架修复组;C组:空白对照组。术后6、12周取材,据大体、组织学、Micro-CT等检测结果对骨软骨修复效果进行评估。[结果]大体观显示A组的软骨修复效果明显优于B组和C组。组织学分析示A组的修复组织主要以透明软骨为主,而B组和C组主要以纤维组织为主。Micro-CT扫描结果表明各种软骨下骨均得到不同程度的重建,A组效果优于其他两组,比较差异有统计学意义。[结论]负载软骨细胞的微载体/藻酸钠水凝胶复合支架能够高效的修复大鼠股骨滑车骨软骨缺损,这种将微载体与水凝胶结合构建复合支架的方法,为组织工程软骨的制备提供了新的途径。     

自体骨髓间充质干细胞复合壳聚糖/羟基磷灰石支架修复兔膝骨软骨缺损

目的 探讨骨髓间充质干细胞(bone mesenehymal stem cells,BMSCs)复合壳聚糖(chitosan,CS)/羟基磷灰石(hydmxyapatite,HA)支架修复兔膝关节局部骨软骨缺损.方法 选健康日本大耳白兔36只,2～3月龄,体重1.7～2.0 kg,每只抽取自体骨髓4～6ml,体外分离培养BMSCs后以2×107/ml密度植于CS/HA支架上体外培养10 h,制成BMSCs-CS/HA支架复合物.将36只实验动物手术制成右膝股骨外侧髁负重区骨缺损模型后,随机分成A、B、C 3组,每组12只.A组植入BMSCs-CS/HA复合物,B组植入单纯CS/HA支架;C组不作任何植入,为空白对照组.分别于术后6周、12周各处死6只动物,取材后进行大体、组织学观察6根据改良Wakitani评分标准进行评分,评估软骨组织的修复情况,并行成组设计方差分析.结果 A组术后6周即可重建关节软骨缺损;修复软骨在观察期内逐渐变厚,软骨下骨有少量骨修复;术后12周透明软骨样修复,表面光整,与周围软骨色泽相近,软骨下骨有部分修复.而B组和C组12周时缺损区仍为纤维软骨样纤维组织修复,色泽浅黄.术后6、12周各组组织学半定量评分显示:股骨髁负重区修复A组评分明显优于B、C组(F=27.26,P＜0.05).结论 自体BMSCs复合CS/HA支架在体内环境下可形成透明软骨修复兔膝关节负重区骨软骨缺损.     

负载重组人骨形态发生蛋白-2壳聚糖纳米微球的制备及异位成骨活性研究

目的 制备负载重组人骨形态发生蛋白-2(rhBMP-2)的壳聚糖纳米微球,并考察其成骨活性. 方法 应用离子交联法制备空白壳聚糖纳米微球和rhBMP-2壳聚糖纳米微球,应用透射电镜观察微球的形态,激光粒径分析仪测定其粒径的分布,检测其载药量、包封率及累积释药率.取24只SD大鼠,随机分为4组,每组6只.以无菌手术分别在大鼠左侧股部建立肌袋.A组大鼠肌袋内植入rhBMP-2壳聚糖纳米微球(含rhBMP-2 1 mg),B组大鼠肌袋内植入rhBMP-2 1 mg,C组大鼠肌袋内植入空白壳聚糖纳米微球,D组大鼠肌袋内不做任何处理.评估rhBMP-2壳聚糖纳米微球的成骨活性.结果离子交联法制备的壳聚糖纳米微球球形规整、分散均匀,微球平均粒径为230.0 nm,分布较集中,包封率为66.87％±4.58％,载药率为(33.44±2.29) μg/mg.A、B、C、D组的ALP活性平均分别为(1.94±0 35)、(1.48±0.56)、(0.20±0.07)及(0.18±0.06) kat/g,差异有统计学意义(F=42.959,P=0.000),A、B组明显高于C、D组,且A组高于B组.4组钙含量平均分别为(5.20±1.42)、(3.80±1.40)、(0.19±0.08)、(0.20±0.08)μg/mg,差异有统计学意义(F=39.242,P=0.000),A、B组明 显高于C、D组,且A组高于B组. 结论 离子交联法可成功制备出均一的rhBMP-2壳聚糖纳米微球,该微球具有良好的载药性能和缓释性能,且其骨诱导活性优于单纯rhBMP-2.     

骨形成蛋白增强自体骨修复股骨头骨缺损的研究

目的　对比评价应用骨形成蛋白 (BMP)增强自体骨与单纯自体骨重建股骨头的不同能力。方法　用健康成年杂种犬 9只 ,以环钻钻入股骨头造成股骨头内骨缺损模型。实验犬分为 A、B、C三组。A组为骨缺损模型组 ,B组取自体同侧大转子骨植入 ,C组取自体大转子骨加 BMP植入。术后 3、6和 9周行 X线片、CT、光镜及电镜观察 ,了解股骨头骨缺损的修复情况。结果　 A组术后 3周可见股骨头骨缺损内血肿机化 ,编织骨形成 ,但骨小梁改建慢 ,9周时编织骨小梁仍未被板层骨小梁取代。B组植入的自体骨坏死 ,9周时仍可见到大量的坏死骨 ,坏死骨主要起到成骨支架的作用。C组术后 3周可见股骨头骨缺损内软骨内成骨及膜内成骨活跃 ,9周时骨缺损已完全由致密的新生板层骨修复。结论　应用单纯自体骨修复股骨头骨缺损仅能发挥成骨支架的作用 ,而自体骨加BMP复合移植能在术后早期 (9周 )有效地重建股骨头内结构 ,是修复重建股骨头骨缺损的好方法     

新型仿生活性人工骨诱导兔腰椎横突间脊柱融合研究

目的采用先进快速成形技术（RP）结合骨组织工程方法研制新型仿生活性人工骨，并探讨其在兔腰椎横突间脊柱融合的应用情况。方法首先采用RP制备薄块型聚乳酸一聚羟乙酸／磷酸三钙（PLGA／TCP）人工骨载体，进而高效复合牛骨形态发生蛋白（bBMP）以制备仿生活性人工骨。扫描电镜观察载体材料及人工骨超微结构。将健康新西兰兔28只（平均体重4.1kg）随机均分为A、B两组（每组14只）。A组：于兔腰4～5右、左侧横突间分别植入仿生活性人工骨（A1组）、自体髂骨（A2组）；B组：于兔腰4～5右、左侧横突间分别植入复合自体新鲜红骨髓的PLGA／TCP载体材料（B1组）、单纯PLGA／TCP载体材料（B2组）。于术后6周和12周，定期大体观察、手法检测、组织学[苏木素-伊红（HE）、三色法及四环素-钙黄绿素荧光检测]和影像学方法（X、CT）系统评价脊柱融合情况。结果RP制备的PLGA／TCP载体具有规则的空间支架结构、相互贯通的孔隙及材料表面微孔特征。这些均有利于bBMP的高效复合。动物实验结果显示，A1组仿生活性人工骨植入具有强的诱骨活性及骨性融合能力，不仅成骨早、新骨形成量大，而且在新骨形成及改塑的同时载体材料逐渐降解。术后12周可形成较为典型的骨小梁及骨髓结构，骨代谢活性亦接近正常。A2组自体髂骨移植能达到良好骨性融合，但术后12周所形成的新骨结构尚须进一步塑形及完善。B1组、B2组术后12周仍遗有较多的载体材料有待降解，基本无成骨能力。术后12周，A1、A2、B1、1324组横突间融合率分别为100．0％、58．3％、18．2％和0％，A1组融合率最高（P〈0．01）。结论先进RP制备的PLGA／TCP载体不仅具有良好的空间超微结构及孔隙特性，而且能高效复合bBMP以正确构建新型组织工程人工骨。该仿生活性人工骨诱导兔横突间脊柱融合获得成功．为生物制造脊柱外科所需的新型、高效人工骨移植材料奠定了重要基础。     

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.     

三种快速成型制作的聚酯/钙磷盐人工骨修复兔桡骨缺损的实验研究

目的检验3种聚酯／钙磷盐植骨材料修复兔桡骨缺损的效果,筛选理想的组织工程用生长因子载体。方法分别采用复合牛骨形态发生蛋白(bBMP)及单纯快速成型工艺制作的3种聚酯／钙磷盐载体材料修复兔桡骨15mm缺损,通过量化评价、影像学、组织学、材料降解及骨密度评价3种聚酯／钙磷盐载体材料修复兔桡骨缺损的效果。结果12周时各材料实验组骨缺损均愈合,各检测指标同对照组比较差异均有统计学意义,空白对照组骨缺损未愈合,以聚乳酸．聚羟基乙酸共聚物／磷酸三钙(PLGA／TCP)材料实验组修复效果最好,聚消旋乳酸／磷酸三钙(PDLLA／TCP)材料实验组次之,最后为聚左旋乳酸／磷酸三钙(PLIA／TCP)材料实验组。结论3种聚酯／钙磷盐材料制作的仿生活性人工骨皆可以修复兔15mm长骨骨缺损,其中以PLGA／TCP材料效果最为理想。     

Exogenous phytoestrogenic molecule icaritin incorporated into a porous scaffold for enhancing bone defect repair

This study was designed to develop a bioactive scaffold to enhance bone defect repair in steroid‐associated osteonecrosis (SAON). Icaritin, a metabolite of the herb Epimedium, has been identified as an angiogenic and osteogenic phytomolecule. Icaritin was homogenized into poly lactic‐co‐glycolic acid/tricalcium phosphate (PLGA/TCP) to form an icaritin‐releasing porous composite scaffold (PLGA/TCP/icaritin) by fine‐spinning technology. In vitro, high performance liquid chromatography was used to determine the release of icaritin during degradation of PLGA/TCP/icaritin. The osteogenic effects of PLGA/TCP/icaritin were evaluated using rat bone marrow mesenchymal stem cells (BMSCs). In vivo, the osteogenic effect of PLGA/TCP/icaritin was determined within a bone tunnel after core decompression in SAON rabbits and angiography within scaffolds was examined in rabbit muscle pouch model. In vitro study confirmed the sustainable release of icaritin from PLGA/TCP/icaritin with the bioactive scaffold promoting the proliferation and osteoblastic differentiation of rat BMSCs. In vivo study showed that PLGA/TCP/icaritin significantly promoted new bone formation within the bone defect after core decompression in SAON rabbits and enhanced neovascularization in the rabbit muscle pouch experiment. In conclusion, PLGA/TCP/icaritin is an innovative local delivery system that demonstrates sustainable release of osteogenic phytomolecule icaritin enhancing bone repair in an SAON rabbit model. The supplement of scaffold materials with bioactive phytomolecule(s) might improve treatment efficiency in challenging orthopedic conditions. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:164–172, 2012     

纳米化仿生诱导骨的构建及促进兔横突间融合研究

目的 探讨纳米化仿生诱导骨促进兔脊柱融合的可行性.方法 成骨化兔脂肪基质细胞(ADSCs)接种在纳米级β磷酸三钙/壳聚糖/聚已内酯基质,构建纳米化仿生诱导骨;建立兔腰5～6横突间融合模型,A组纳米化仿生诱导骨,B组自体髂骨,C组脂肪基质细胞移植,D组空白支架,E组rhBMP-2注射.行影像学、组织学、免疫组化、新骨及诱导因子定量分析等检查.结果 A组融合能力最强,融合率100%、新骨面积比(87.32±1.68)%、BMP含量及力学指标(128±19)、(331.56±3.21)N、(526.78±3.19)Nmm均高于其他组,差异有统计学意义(P＜0.05);B、C组次之,E组新骨生长不明显,融合相对延缓.D组未融合.结论 仿生诱导骨能强化骨再生,促进脊柱融合.     

Locally delivered rhBMP-2 enhances bone ingrowth and gap healing in a canine model.

The purpose of the present study was to determine if recombinant human bone morphogenetic protein-2 (rhBMP-2) enhances bone ingrowth into porous-coated implants and gap healing around the implants. In the presence of a 3-mm gap between the implant and host bone, porous-coated implants were placed bilaterally for four weeks in the proximal humeri of skeletally mature, adult male dogs. In three treatment groups, the test implant was treated with HA/TCP and rhBMP-2 in buffer at a dose of 100 microg/implant (n=5), 400 microg/implant (n=6), or 800 microg/implant (n=5) and placed in the left humerus. In these same animals, an internal control implant was treated only with HA/TCP and buffer and placed in the right humerus. These groups were compared with a previously reported external control group of seven animals in which no growth factor was delivered [J. Orthop. Res. 19 (2001) 85]. The BMP treated implants in the two lower dose groups had significantly more bone ingrowth than the external controls with the greatest effect in the 100 g/implant group (a 3.5-fold increase over the external control, p=0.008). All three dose groups had significantly more bone formation in the 3-mm gap surrounding the BMP treated implants than the external controls with the greatest effect in the 800 microg group (2.9-fold increase, p<0.001). Thus, application of rhBMP-2 to a porous-coated implant stimulated local bone ingrowth and gap healing. The enhancement of bone formation within the implant (bone ingrowth) was inversely related to dose.     

BMP复合仿生人工骨填塞犬股骨假体周围髓腔骨缺损的实验研究

目的评估仿生人工骨（PLGA／TCP）材料作为BMP缓释系统载体材料修复犬假体涂层多孔钛周围骨缺损的可行性。方法给予8只犬进行右侧股骨头置换术，并充分扩髓，周围填充BMP复合的PLGA／TCP骨移植材料，应用X线拍片、组织和荧光观察、EDX及SEM检测、骨密度定量分析等方法，观察负重情况下该材料的实际效果。结果术后X线显示，未有出现透亮带、无假体下沉，未见骨质吸收；20周时骨与假体之间紧密接触，多孔钛内骨组织明显长入，以编织骨为主。植入的活性人工骨已经完全降解，骨小梁结构成熟；假体植入肢体与非手术肢体骨密度之比，显示在术后1个月假体植入侧的骨密度值有所降低，而后逐渐升高。结论多孔钛涂层有助于假体内骨与假体的固定，BMP复合PLGA／TCP作为新的骨移植材料应用于关节外科，有广泛的潜力和价值。     

VEGF scaffolds enhance angiogenesis and bone regeneration in irradiated osseous defects.

Bone regeneration is challenging in sites where the blood supply has been compromised by radiation. We examined the potential of a growth factor (VEGF) delivery system to enhance angiogenesis and bone formation in irradiated calvarial defects. VEGF-releasing polymers significantly increased blood vessel density and vascular perfusion in irradiated defects and increased bone formation relative to control conditions. INTRODUCTION: Radiation therapy causes damage to tissues and inhibits its regenerative capacity. Tissue injury from radiation is in large part caused by a compromised vascular supply and reduced perfusion of tissues. The aim of this study was to determine if delivery of vascular endothelial growth factor (VEGF) from a biodegradable PLGA (copolymer of D,L-lactide and glycolide) scaffold could enhance neovascularization and bone regeneration in irradiated osseous defects. MATERIALS AND METHODS: An isolated area of the calvarium of Fisher rats was irradiated (12 Gy) 2 weeks preoperatively, and two 3.5-mm osseous defects were created in this area, followed by the placement of PLGA scaffolds or VEGF scaffolds (PLGA scaffolds with incorporated VEGF) into the defects. Laser Doppler perfusion imaging was performed to measure perfusion of these areas at 1, 2, and 6 weeks. Implants were retrieved at 2, 6, and 12 weeks, and histologic and muCT analyses were performed to determine neovascularization and bone regeneration. RESULTS: Histological analyses revealed statistically significant increases in blood vessel formation (>2-fold) and function (30%) within the VEGF scaffolds compared with PLGA scaffolds. Additionally, evaluation of bone regeneration through bone histomorphometric and muCT analyses revealed significantly greater bone coverage (26.36 +/- 6.91% versus 7.05 +/- 2.09% [SD]) and increased BMD (130.80 +/- 58.05 versus 71.28 +/- 42.94 mg/cm(3)) in VEGF scaffolds compared with PLGA scaffolds. CONCLUSIONS: Our findings show that VEGF scaffolds have the ability to enhance neovascularization and bone regeneration in irradiated osseous defects, outlining a novel approach for engineering tissues in hypovascular environments.