移植骨复合骨髓基质干细胞修复兔股骨缺损

目的观察同种异体骨复合骨髓基质干细胞对兔股骨大段缺损修复情况,探讨其修复骨缺损的可行性。方法将24只大耳兔随机分为2组,造成股骨大段缺损,对照组植入打孔同种异体骨,实验组植入打孔同种异体骨＋明胶海绵＋骨髓基质干细胞。术后2个月行X线片观察、病理组织学检查及骨密度测试。结果①放射学检查：对照组在异体骨结合部可见骨痂通过,实验组整个异体骨段均可见明显骨痂形成。②病理组织学检查：对照组可见少量内骨痂及外骨痂且被大量纤维结缔组织所分隔,实验组异体骨有坏死后弧形吸收窝,可见内外骨痂生长,髓腔内充满大量骨母细胞。③平均骨密度值测定：实验组高于对照组及正常股骨,差异有显著性（P〈0．05）。结论同种异体骨复合骨髓基质干细胞用于修复兔股骨大段缺损,较单纯异体骨成骨量大、迅速,能够对骨缺损进行有效的修复。     

复合骨形态蛋白-2的聚乳酸-乙醇酸共聚物/磷酸三钙人工骨结合带血供骨膜修复羊大段骨缺损

目的 研究复合骨形态蛋白-2的聚乳酸-乙醇酸共聚物/磷酸三钙(PLGA-TCP-BMP-2)人工骨结合自体带血供尺骨骨膜移植修复大段骨缺损的效果. 方法 手术造成30 mm绵羊桡骨骨缺损,A组植入PLGA-TCP-BMP-2人工骨及带血运的尺骨骨膜,B组仅植入PLGA-TCP-BMP-2人工骨,C组不植入任何材料.3组均以钢板固定骨缺损区.术后24周拍摄X线片并处死动物,进行组织学观察评价. 结果 X线检查示A组桡骨缺损处完全成骨修复,皮质骨与髓腔的轮廓清晰;B组亦完全修复,但新生骨密度及髓腔轮廓清晰度均不如A组;C组无有效骨痂形成.组织学检查示A、B组骨痂外层形成为板层骨,C组缺损区可见大量纤维组织填充. 结论 PLGA-TCP-BMP-2人工骨结合自体带血供尺骨骨膜移植能够很好的修复绵羊桡骨30 mm的骨缺损.     

冷冻同种异体皮质骨复合重组人骨形态发生蛋白-2修复兔大段负重骨缺损

我们将深低温冷冻同种异体皮质骨与重组人骨形态发生蛋白 2 (rhBMP 2 )、Ⅰ型可吸收胶原海绵 (ACS)复合 ,植入兔股骨大段缺损处 ,探讨其修复功能。一、材料与方法1.试剂与异体骨 :rhBMP 2 (北京军事医学科学院 ) ;Ⅰ型可吸收胶原海绵(ACS ,北京益而康生物有限公司 ) ;-80℃深低温冰箱保存同种异体皮质管状骨(自制 )。2 .动物分组 :健康新西兰大白兔 40只 ,体重 2 .5～ 3 .0kg ,雌雄不分。随机分成 5组 ,每组 8只兔。A组 :植入异体骨 +rhBMP 2 +ACS ;B组 :植入异体骨+rhBMP 2 ;C组 :植入异体骨 +ACS ;D组 :单纯植入异体骨 ;E组 …     

自固化磷酸钙复合BMP及同种异体骨修复兔股骨大段骨缺损

[目的] 观察一种新型自固化磷酸钙（CPC）复合BMP与同种异体骨修复兔股骨节段性骨缺损的效果，为临床复合应用大段同种异体骨移植提供参考。[方法] 54只新西兰大白兔随机分成3组，于一侧股骨中上段造成2cm长皮质骨缺损模型，分别进行：A组复合BMP与CPC的新鲜冷冻同种异体骨移植；B组单纯新鲜冷冻同种异体骨移植；C组自体大段骨移植。移植骨均用直径3mm三棱髓内针固定。于术后4、8、12周，进行影像学、组织学检查，对比各组移植骨愈合过程与修复效果。[结果] CPC复合BMP大段同种异体骨移植早期骨修复效果优于单纯异体骨移植（P〈0．01），与自体骨移植修复效果相似，至12周3组均达骨性愈合，以A组及C组骨修复塑形较好。CPC复合BMP组骨痂量较多，分布于移植骨与宿主骨结合部及移植骨周围，形成皮质骨外骨桥，并较早在异体骨外表面形成破骨与成骨，异体骨内哈佛氏管扩大，衬垫细胞、成骨细胞、破骨细胞及血细胞较其它组多。CPC随着新骨的形成及改建塑形逐步缓慢降解。[结论] CPC复合BMP对大段同种异体骨移植的愈合及替代有增强和促进作用。     

抗结核骨组织工程复合体局部治疗兔脊柱结核的对比研究

目的探讨以羟基磷灰石与/β-磷酸三钙(hydroxyapatite and/β-tricalcium phosphate,HA/β-TCP)复合体材料及同种异体骨为支架材料构建的抗结核性骨组织工程复合体,评价两种不同抗结核骨组织复合体治疗兔脊柱结核的效果。方法取3月龄经造模成功后的新西兰大白兔36只,行病灶清除术,随机分为3组,每组12只,A组于骨缺损处植入利福喷丁微球-rADSCs/HA/β-TCP抗结核骨组织工程复合体,B组于骨缺损处植入利福喷丁微球-rADSCs/同种异体骨抗结核骨组织工程复合体,C组清创后未做任何处理。术后4、8、12周行影像学(DR)检查,术后第12周将实验动物处死,取标本,行大体观察、组织病理学观察骨缺损修复情况。结果大体观察发现A组骨缺损区被新生骨组织取代;B组骨缺损基本修复,周边可见大量骨组织形成;C组骨缺损处有少量骨组织形成,可见大量纤维组织覆盖。X线观察发现:4周时,A组骨缺损区可见少量骨痂形成,材料与周围骨组织紧密接触。B组骨缺损区可见骨痂形成,C组骨缺损区界限清晰,可见片状低密度影。8周时,A组骨缺损区明显缩小,材料吸收,边界稍模糊。B组骨缺损区可见片絮状高密度影,C组骨缺损区可见点状钙化影。12周时,A组骨缺损区材料基本吸收,B组骨缺损材料部分吸收,椎间隙部分融合,C组骨缺损区界线尚清,椎间隙破坏缺损。组织病理学检查发现:术后12周,A组材料吸收明显,可见大量纤维骨痂组织生成骨组织。B组可见部分同种异体骨残留,周边可见大量纤维骨痂组织生成骨组织。C组可见大量纤维组织形成。结论利福喷丁微球-rADSCs/HA/β-TCP构建的抗结核骨组织工程复合体具有良好的生物相容性,能够有效填充兔腰椎结核病灶清除术后的骨缺损。     

脱脂程序对异体松质骨免疫原性影响的实验研究

[目的]研究脱脂程序对异体松质骨免疫原性的影响,并探讨其可能的机制。[方法]采用4种不同程序处理待移植异体骨块,检测处理后各组骨块总脂肪和总蛋白含量。根据待移植骨块的不同将受体大鼠分为4组,行双侧股部肌囊袋内骨块植入。于术后1、2、4、8周取材,检测体外淋巴细胞二次刺激增殖指数、血CD4+/CD8+细胞比值,并进行组织学观察。对术后4周时各组的免疫反应指标同相应骨块总脂肪含量行相关分析。[结果]骨块内总脂肪含量为A组B组C组D组。对移植术后体外淋巴细胞二次刺激增殖指数及血淋巴细胞CD4+/CD8+比值测定发现:同一时间点各组水平均为A组B组C组D组,且均于术后4周时达到峰值。各组骨块总脂肪含量同移植术后4周时体外淋巴细胞二次刺激增殖指数、血淋巴细胞CD4+/CD8+比值呈正相关。组织学观察示移植早期各组骨块周围炎性细胞浸润程度:A组B组C组D组;D组在术后4周时可见血管长入,8周时可见新骨的形成。[结论]脱脂程序可有效降低异体松质骨移植后免疫反应,并可能提高移植后的成骨能力。总脂肪含量可作为提示异体骨移植后免疫反应强弱的一个指标。     

PLGA-TCP-BMP-2人工骨结合带血供自体骨修复骨缺损

[目的]研究PLGA-TCP-BMP-2人工骨结合自体带血供自体尺骨移植修复大段骨缺损的效果.[方法]手术造成30 mm绵羊桡骨骨缺损,A组置入PLGA-TCP-BMP-2人工骨及带血运的长段尺骨,B组仅置入PLGA-TCPBMP-2人工骨,C组不置人任何材料.3组均以钢板固定骨缺损区.术后24周拍摄X线片并处死动物,进行组织学观察评价.[结果]X线检查示A组桡骨缺损处完全成骨修复,皮质骨与髓腔的轮廓清晰;B组亦能完全修复,但新生骨密度及髓腔轮廓清晰度均不如A组;C组无有效骨痂形成.组织学检查示A、B组骨痂外层形成为板层骨,C组缺损区可见大量纤维组织填充.[结论]PLGA-TCP-BMP-2人工骨结合自体带血供长段尺骨移植能够很好的修复绵羊桡骨30 mm的骨缺损.     

自体和异体骨髓间充质干细胞移植对家兔股骨头缺血性坏死治疗作用的比较研究

目的 比较同种异体和自体骨髓间充质干细胞(BMSCs)移植,对实验性家兔股骨头缺血性坏死的治疗作用;为建立BMSCs库及临床应用,提供实验证据.方法 采用新西兰大白兔液氮冷冻法造模,随机分为对照组(A),髓芯减压组(B),自体细胞移植组(C)和同种异体细胞移植组(D);对术后2、4、6、8周的标本,进行X线和组织学观察.结果 (1)X线检查显示:2周时,A组股骨头标本呈高密度,随时间延长,骨密度进一步增加,并出现骨小梁结构的紊乱和囊性变,8周时变化最为显著.2周时,在B、C、D组股骨头钻孔区的边缘,出现密度增加;8周时,在B组股骨头钻孔区的周围,形成硬化线.在C、D组钻孔区,出现骨小梁结构.(2)组织学观察表明:液氮冷冻后,A组股骨头标本出现骨坏死和修复的病理变化.8周时B组钻孔区修复不完全.2周时C、D组钻孔区,均有大量移植的BMSCs存在;4周时两组钻孔区内,充满了新生骨小梁结构;在8周时钻孔区内,骨小梁趋于成熟.而且,C、D两组间骨小梁面积的图像分析,其差异无统计学意义.结论 同种异体和自体:BMSCs移植,对实验性家兔股骨头缺血性坏死的治疗,呈现相似的结果:建立BMSCs库供临床应用,具有较大的可行性.     

黄骨髓对兔骨折愈合影响的实验研究

[目的]研究自体黄骨髓一期移植对骨折愈合作用的实验疗效,观察黄骨髓是否具有成骨能力,为进一步临床应用提供理论依据。[方法]36只新西兰大白兔随机分为3组,建立左侧胫骨骨折延迟愈合模型,A组仅以钢板内固定;B组钢板内固定后,植入空白明胶海绵,C组钢板内固定后,植入黄骨髓与明胶海绵复合物。术后每组分别于2、4、8、12周各处死3只动物,进行影像学检测、大体观察及HE染色检查,观察骨折愈合情况及骨痂形成情况。[结果]A组及B组在术后4周只可见少量骨痂形成,而C组在术后2周即可见骨痂形成,术后4周可见大量骨痂形成,至术后8周C组骨折线消失,而A、B组骨折线仍可见;术后12周,A、B组仍可见骨折线存在。[结论]黄骨髓在骨折后能明显促进骨折愈合,在预防骨不连或骨折延迟愈合中具有重要作用。     

兔关节软骨下骨缺损骨移植后移植骨组织学变化实验研究

目的观察兔关节软骨下骨缺损后行骨水泥+自体骨或骨水泥+同种异体骨修复术后不同时间点移植骨组织学变化情况。方法选取30只成年健康新西兰大白兔,随机分为自体骨和同种异体骨组,每组各15只。模拟临床骨巨细胞瘤病灶刮除术,建立关节软骨下骨缺损动物模型,分别填充不同材料修复骨缺损。自体骨组填充骨水泥+自体骨,同种异体骨组填充骨水泥+同种异体骨,分别于术后4、6、8周取出植入骨。先行大体观察,然后通过HE染色切片观察其组织学变化。两组术后4、6、8周植入骨内成骨细胞和破骨细胞数量比较采用两因素方差分析,组间两两比较采用LSD法。P0.05为差异有统计学意义。结果术后4周自体骨组植入骨骨小梁开始吸收,植骨周围存在部分新生毛细血管和少量中性粒细胞,移植骨与宿主骨相邻的骨基质内可见少量骨细胞和破骨细胞,骨再生现象形成;同种异体骨组植入骨骨小梁未见明显吸收,植骨区可见肉芽组织,骨再生现象不明显。术后6周自体骨组植入骨骨小梁大部分被吸收,骨基质边缘新生毛细血管和新生成骨细胞增多,移植骨周边可见多核破骨细胞和排列不规则的编织骨,为成骨初期;同种异体骨组植入骨可见散在骨小梁及纤维结缔组织包绕死骨,存在溶骨现象,骨基质边缘可见少量新生毛细血管,破骨细胞及成骨细胞数量极少,无编织骨形成。术后第8周自体骨组植入骨骨小梁被吸收,可见大量新生骨、新生毛细血管和板层骨,骨基质边缘有排列较密集的成骨细胞,编织骨较术后6周时体积变小且排列逐步规整;同种异体骨组植入骨周围可见少量新生毛细血管,部分区域钙盐沉积较明显,少量新生骨小梁形成,其周围可见少量成骨细胞和破骨细胞,部分坏死钙化区内有板成骨形成。同种异体骨组术后第4、6、8周成骨细胞数量及术后第4、8周破骨细胞数量均低于自体骨组(P均0.05)。自体骨组和同种异体骨组术后第6、8周成骨细胞数量均高于术后第4周(P均0.05),自体骨组术后第8周成骨细胞数量高于术后第6周(P0.05)。自体骨组术后第8周破骨细胞数量均高于术后第4、6周(P均0.05),同种异体骨组术后第6周破骨细胞数量高于术后第4、8周(P均0.05)。结论关节软骨下骨缺损填充骨水泥+自体骨较填充骨水泥+同种异体骨植入骨区骨融合率高,成骨效能较好,术后不同时间点自体骨成骨细胞和破骨细胞表达较同种异体骨活跃。     

Perforations of cortical bone allografts improve their incorporation

The incorporation of perforated cortical bone allografts was compared with non-perforated allografts. A 5-cm circumferential defect in the middiaphysis at the tibia was created in adult sheep. A frozen tibial allograft was implanted and fixed with a locked nail for 6 months. There was no postoperative immobilization. Group I consisted of eight sheep with non-perforated allografts, whereas Group II was comprised of 10 sheep with perforated allografts. Union was evaluated radiographically, whereas the central part of the allograft had a densitometric evaluation. Creeping substitution was assessed on microradiographs from cross-sections of the central 3 cm of graft by measurement of porosity and percentage of new and old bone area within the confines of the graft. The width of periosteal and endosteal callus also was determined. There was no statistical difference between both groups for the union score and bone density. However, the cortical bone graft porosity and the amount of new bone within the cortical bone differed significantly between the perforated allografts and the non-perforated ones. Periosteal callus was similar in both groups, whereas endosteal callus was significantly more wide and extended in the perforated allografts. Perforation of a cortical bone substantially improved the amount of newly formed bone by the host when compared with a non-perforated bone. The creation of channels seemed to increase the interface between living soft tissues of the host and the allografted bone with a resulting enhanced incorporation.     

Effect of intramedullary polymethylmethacrylate and autogenous cancellous bone on healing of frozen segmental allografts

This study was designed to compare bone mineral density, periosteal callus production. new bone formation, bone porosity, histologic appearance, and union of mid-diaphyseal segmental allografts of the femur stabilized with an interlocking nail technique in a canine model 4 months after the procedure. An in vivo study was performed to compare the effects of augmenting interlocking nail fixation with an interlocking nail alone, intramedullary polymethylmethacrylate, intramedullary polymelhylmethacrylate and autogenous cancellous bone applied to the periosteal surface of the host-allograft junction, autogenous cancellous bone applied to the endosteal surface of the allograft, autogenous cancellous bone applied to the periosteal surface of the host-allograft junction, and autogenous cancellous bone applied to the periosteal surface of the hostallograft junction and to the endosteal surface of the allograft. There were no differences among treatments for bone mineral density at any time interval. Callus area 4 weeks after the procedure was greater along the lateral and cranial surfaces for treatments with periosteal cancellous bone (p < 0.05). New bone within the allograft segment did not differ among treatments and was reduced compared with the host-allograft junctions (p < 0.05). The amount and quality of bone tissue at the host-allograft junctions were greatest with treatments of intramedullary polymethylmethacrylate and autogenous cancellous bonc applied to the periostcal surface of the host-allograft junction and of autogenous cancellous bone applicd to the periosteal surface of the host-allograft junction and to the endosteal surface of the allograft (p < 0.05). The rate of bone union was lower, and there was a greater gap (non-bone tissue) remaining between host and allograft bone with treatment involving just intramedullary polymethylmethacrylate than with other treatments (p < 0.05). The results suggest that augmenting interlocking nail fixation with intramedullary polyrnethylmethacrylate by itself offers no advantage but that a combination of intramedullary polymethylmethacrylate and cancellous bone at the periosteal surface or of cancellous bone within the medullary canal and at the periosteal surface improves the quality of healing at 6 months.     

他汀类药物对同种异体骨移植修复兔桡骨缺损的影响

目的观察他汀类药物对骨折愈合质量的影响及影响骨代谢的可能机制。方法制备同种异体松质骨。将36只新西兰白兔随机分为3组,在两侧桡骨干中段处造成长10mm的骨缺损,以制备骨缺损动物模型。A组为同种异体骨移植复合他汀类药物局部应用(12只),术后第1天于骨折局部皮下注射5%辛伐他汀液(5mg/kg)1次,后连续注射5天,1日2次;B组为同种异体骨复合骨形态发生蛋白移植(12只);C组为单纯同种异体骨移植(12只)。术后2、4、8、12周行大体观察、X线摄片检查、骨密度检查、病理学检查和生物力学检查。术后12周用生物力学试验机作三点弯曲试验,并与正常桡骨比较。结果术后各组均无明显的免疫排斥反应。X线摄片检查、骨密度检查、病理学检查结果表明,同种异体骨移植复合他汀类药物局部应用组(A组)无论在新骨成骨量、成骨速度和时间上均优于单纯同种异体骨移植组(C组)。术后12周的X线片和病理学检查结果显示A、B两组差别不大,基本达到骨愈合。生物力学检查结果示A组的三点弯曲试验最大应力明显高于C组(P<0.01),A组和B组无统计学差异,但B组的最大应力值略高于A组。结论辛伐他汀(10mg/kg/d)局部应用可促进兔桡骨缺损经同种异体骨移植后的骨愈合质量。     

Bone mass and microarchitecture of irradiated and bone marrow-transplanted mice: influences of the donor strain

Summary  Total body irradiation and bone marrow transplantation induced dramatic trabecular bone loss and cortical thickening in mice. Transplanted cells were engrafted in bone marrow, along trabeculae, and in periosteal and endosteal envelopes. None of the osteocytes were of donor origin. Bone microarchitecture of transplanted mice changed to tend toward the donor phenotype. Introduction  Osteopenia and osteoporosis are complications of bone marrow transplants (BMT) attributed to related chemotherapy. However, the specific influence of total body irradiation (TBI) is unknown. Methods  We investigated the effects of TBI and BMT on bone mass and microarchitecture by micro-CT. Eighteen C57Bl/6 (B6) mice receiving lethal TBI had a BMT with marrow cells from green fluorescent protein--transgenic-C57Bl/6 (GFP) mice. Transplanted (T^GFPB6), B6, and GFP mice were euthanized 1, 3, and 6 months after BMT or at a related age. Results  T^GFPB6 presented a dramatic bone loss compared with B6 and did not restore their trabecular bone mass over time, despite a cortical thickening 6 months after BMT. Serum testosterone levels were not significantly reduced after BMT. During aging, GFP mice have less trabeculae, thicker cortices, but a narrower femoral shaft than B6 mice. From 3 months after BMT, cortical characteristics of T^GFPB6 mice differed statistically from B6 mice and were identical to those of GFP mice. GFP⁺ cells were located along trabecular surfaces and in periosteal and endosteal envelopes, but none of the osteocytes expressed GFP. Conclusion  Our findings suggest that engrafted cells did not restore the irradiation-induced trabecular bone loss, but reconstituted a marrow microenvironment and bone remodeling similar to those of the donor. The effects of irradiation and graft on bone remodeling differed between cortical and trabecular bone.     

骨髓间质干细胞复合脱钙骨基质和骨形态发生蛋白行兔腰椎横突间融合

 目的 探讨骨髓间质干细胞复合脱钙骨基质和骨形态发生蛋白进行兔腰椎横突间融合的效果。
方法 体外分离、培养骨髓间质干细胞,复合于脱钙骨基质材料,以骨形态发生蛋白进行成骨化诱导。日本大耳白兔60只,随机分为三组,A组以骨髓间质干细胞+脱钙骨基质+骨形态发生蛋白、B组以脱钙骨基质、C组以自体髂骨行L_5,6横突间融合。术后8周取腰椎标本,评估植入材料融合情况;行DR片灰度分析,计算成骨密度及成骨面积;行CT扫描三维重建观察横突间融合形态。HE染色分析横突间融合组织结构。
结果 大体可见A组及C组植入材料与宿主横突融合,融合组织质地硬,形态不规整;B组横突间植入材料大部分被吸收。DR片示A组与C组横突间呈高密度影,成骨密度不均;B组未达到骨性融合。CT示A组与C组融合标本有明显的连续骨痂通过横突间区;B组未见连续骨痂。A组成骨密度和成骨面积均高于B组,与C组无差异。组织学观察示A组与C组大量软骨形成,靠近横突处新生骨小梁形成;B组横突间连接主要为纤维组织。
结论 骨髓间质干细胞复合脱钙骨基质和骨形态发生蛋白行兔腰椎横突间融合,其成骨能力接近自体髂骨,优于单纯应用脱钙骨基质。     

Skeletal actions of intermittent parathyroid hormone: effects on bone remodelling and structure

Intermittent administration of parathyroid hormone peptides has anabolic skeletal effects and reduces fracture risk in postmenopausal women with osteoporosis but the cellular and structural mechanisms by which these effects are mediated have not been fully established. In cancellous and endocortical bone, there is evidence that both modelling and remodelling-based formation contribute to the increase in bone mass although the contribution of these at different time points in the response to PTH has not been established. Despite the large increase in spine bone mineral density, however, significant increases in iliac crest cancellous bone volume and trabecular thickness have not been consistently demonstrated, possibly reflecting site-specific differences in PTH-induced skeletal effects and/or the large sampling and measurement variance associated with assessment of iliac crest cancellous bone volume and structure. In iliac crest cortical bone, increased cortical thickness has been demonstrated, due at least in part to increased endosteal bone formation; there is also some evidence for increased formation on periosteal surfaces. At some sites an increase in cortical porosity may also occur and the overall effects on cortical bone strength, particularly at the hip, remain to be established. Studies in iliac crest bone indicate a trend towards a lower mineralisation density of bone matrix and increased heterogeneity of mineralisation, consistent with new bone formation. In addition, there is a reduction in mineral crystallinity and a shift towards more divalent collagen cross-links, indicating a change towards a younger bone profile.

The potential clinical implications of these effects on bone are currently unknown. The stimulatory effect of PTH peptides on bone formation may favour their use in low turnover bone disease and in states of advanced bone loss. Furthermore, if beneficial effects on cortical bone strength are confirmed, efficacy at non-vertebral sites might be superior to those observed with antiresorptive drugs. Better definition of the effects of intermittent PTH administration on cancellous and cortical bone remodelling and structure at different skeletal sites may inform these speculations and is an important area for future research.     

Cortical bone remodeling in normal rat

Summary Cortical bone remodeling along the femur diaphysis was determined in normal female rats (Sprague-Dawley) with the tetracycline technique.Three segments on the cortical bone circumference (the anterolateral, the medial, and the posterior) were found to be most suitable for the study of the remodeling process. Oxytetracycline was administered at age 60 and 75 days, and groups of animals were killed at age 75, 85, 95, and 105 days.The accumulated endosteal growth during age 60 to 75 days in the anterolateral segment was found to increase uniformly in the distal direction along the femur diaphysis. A method is described where this accumulated endosteal growth is used. This method eliminates the use of calipers to determine the section level and makes it possible to study comparable sections even after varying periods of time.The proximal part of the diaphysis showed periosteal apposition in all three segments. The periosteal apposition turned into resorption in the distal part of the diaphysis in the anterolateral and medial segments, whereas the periosteal appsition increased in the posterior segment.The endosteal growth increased in the distal direction in the anterolateral and medial segments. Irregular OTC bands made measurements of endosteal remodeling in the posterior segment impossible.The cortical width decreased in the distal direction along the femoral shaft. Comparison between the different age groups is described and also the relation between the accumulated endosteal growth and the diameter of the medullary cavity.     

Flurbiprofen enhances growth and cancellous and cortical bone accumulation in rapidly growing long bones

The effects of flurbiprofen, a non-steroidal anti-inflammatory drug, on bone growth was studied by static and dynamic histomorphometry in immature (28 days old) male Sprague-Dawley rats. Flurbiprofen at 0, 0.02, 0.1, 0.5 or 2.5 mg/kg/d doses was given subcutaneously daily for 21 days. The 0.1 and 0.5 mg/kg/d doses were most effective in stimulating longitudinal and radial bone growth and enhancing the accumulation of cancellous and cortical bone. Proximal tibial longitudinal bone growth rate, growth plate thickness, and periosteal bone formation rate were increased 30-40%, while cortical bone (tibial shaft) and cancellous bone (proximal tibial metaphysis) accumulated 12% and 90% more bone than controls, respectively. Enhanced accumulation of cortical bone was attributed to stimulated periosteal bone formation without accompanying marrow cavity enlargement. Enhanced accumulation of cancellous hard tissue was postulated to be due to reduced trabecular bone resorption and no effect on bone formation. The cell counts support these conclusions. There was a decrease in osteoclast numbers (-62 to -70%), an insignificant decrease in osteoblast numbers (-5 to -30%) per mm of bone surface and a decrease in osteoclast to osteoblast ratio (-35 to -56%). The findings presented are compatible with the conclusion that flurbiprofen, induced changes in rapidly growing long bones by reducing osteoclast activity and recruitment, stimulating longitudinal and radial growth, increasing the cortical bone mass by stimulated periosteal bone growth and depressed endosteal resorption, and increasing cancellous bone mass by depressed trabecular bone resorption without affecting bone formation.     

骨髓基质干细胞联合血管束植入构筑血管化组织工程骨修复兔大段骨缺损

目的 研究兔骨髓基质干细胞(BMSCs)联合动静脉血管束植入异种脱蛋白松质骨(XDCB)构筑血管化组织工程骨修复兔桡骨中远段完全骨膜骨缺损的能力. 方法 从兔髂嵴捕骨髓培养制备兔BMSCs,将第5代BMSCs种植于多孔XDCB,并进行成骨诱导2周制备组织工程骨,手术中分离兔桡动、静脉血管束.动物模型为制备24只兔舣侧桡骨中远段完全骨膜骨缺损1.5 cm共48侧,分4组修复(n=12),A组为空白未治疗组,B组为单纯材料+血管束植入组(XDCB+VB),C组为组织工程骨组(XDCB+BMSCs),D组为组织工程骨+血管束植入组(XDCB+BMSCs+VB),符组交叉配对.分别于术后4、8、12周行X线片、大体解剖、组织切片、生物力学等检查,观察各组骨缺损修复效能及移植物血管化情况.结果 D组骨缺损修复效能(术后12周新骨面积比2.02%±0.16%)及血管化情况(术后12周血管面积比6.89%±0.32%)优于C组(1.50%±0.28%和3.17%±0.19%),而C组又优于B组(1.59%±0.19%和6.52%±0.23%),A组骨缺损未修复,各组结果差异有统计学意义(P<0.05).结论 BMSCs联合动静脉血管束植入构筑的血管化组织工程骨能促进成骨过程和新生骨的血管化,显著提高组织工程骨修复大段骨缺损的能力.     

Biological and mechanical changes of the bone graft–cement interface after impaction allografting

In impaction allografting, the host bone interface may consist of morsellized allograft alone or as a composite with bone cement. The objective of this study was to investigate the temporal changes in the interface for these two materials in a rat bone chamber model. To simulate the impaired endosteal circulation after impaction allografting, bone chambers were tightened bilaterally to the endosteal surfaces of proximal tibiae of mature rats and filled with pure allograft or cement/allograft composite. The cement/allograft composite-host bone interface strength was significantly higher at 3 weeks and was higher than the allograft construct failure strength. Limited allograft, but extensive periosteal remodeling, was observed at 3 weeks which resulted in a significantly increased cortical porosity and cortical thickness. The allograft porosity decreased significantly at 6 weeks indicating extensive remodeling of the allograft bone. Little or no remodeling of the allograft particles in the cement was found. At 6 weeks a new medullary canal was formed, and the endosteal cortex was partially absorbed. Endosteal absorption resulting in medullary canal widening in revision THR may be responsible for clinically unstable stems after impaction allografting.