Evaluation of the Biocompatibility and Osteogenic Properties of Metal Oxide Coatings Applied by Magnetron Sputtering as Potential Biofunctional Surface Modifications for Orthopedic Implants

Biomaterials with adequate properties to direct a biological response are essential for orthopedic and dental implants. The surface properties are responsible for the biological response; thus, coatings with biologically relevant properties such as osteoinduction are exciting options to tailor the surface of different bulk materials. Metal oxide coatings such as TiO₂, ZrO₂, Nb₂O₅ and Ta₂O₅ have been suggested as promising for orthopedic and dental implants. However, a comparative study among them is still missing to select the most promising for bone-growth-related applications. In this work, using magnetron sputtering, TiO₂, ZrO₂, Ta₂O₅, and Nb₂O₅ thin films were deposited on Si (100) substrates. The coatings were characterized by Optical Profilometry, Scanning Electron Microscopy, Energy-Dispersive X-ray Spectroscopy, X-ray Photoelectron Spectroscopy, X-ray Diffraction, Water Contact Angle measurements, and Surface Free Energy calculations. The cell adhesion, viability, proliferation, and differentiation toward the osteoblastic phenotype of mesenchymal stem cells plated on the coatings were measured to define the biological response. Results confirmed that all coatings were biocompatible. However, a more significant number of cells and proliferative cells were observed on Nb₂O₅ and Ta₂O₅ compared to TiO₂ and ZrO_2. Nevertheless, Nb₂O₅ and Ta₂O₅ seemed to induce cell differentiation toward the osteoblastic phenotype in a longer cell culture time than TiO₂ and ZrO₂.     

A Novel Alveolar Distractor Incorporating Nickel–Titanium Alloy Springs: A Preliminary In Vitro Study

A new design of an alveolar distractor using nickel–titanium (NiTi) open-coil springs was developed and investigated to produce distraction forces against the tensile forces of porcine attached gingiva to simulate human gingiva. We subjected 15 mm long NiTi open-coil springs (Highland and ORMCO) with three levels of forces (light, medium and heavy) to mechanical testing in a 37 ± 1 °C water bath. Ten strips of porcine mandibular attached gingiva were subjected to tensile tests to determine the resistance force. The forces from the springs were compared with the tensile forces from the porcine attached gingiva. Data between groups were analyzed with independent-samples T-tests (p-value < 0.05). The tensile strength and the Young modulus were greater in buccal compared to lingual porcine attached gingiva. Compared to other spring dimensions and companies, forces generated from 0.014 × 0.036″ ORMCO springs were the highest and could overcome the tensile resistance from porcine attached gingiva over the longest distraction range of 1.6 mm. This preliminary in vitro study introduced a new design of an alveolar distractor incorporated with NiTi open-coil springs that could generate light and continuous forces to overcome the resistance from porcine attached gingiva.     

H型血管在骨质疏松症中的研究进展

骨质疏松症是一种全身性骨病,具有骨微结构退化、骨密度低的特点,在世界范围内发病率较高。随着我国人口逐渐进入老龄化,骨质疏松症的发病率日益上升,已经成为威胁老年人群生活质量的重要因素,给公共卫生系统带来了难以预料的挑战。近年来,许多文献报道骨内特殊型血管——H型血管生成与骨生成之间存在耦合,为骨质疏松症的治疗提供了新的研究目标。本文就H型血管的结构及功能、参与H型血管生成与成骨的细胞因子以及其他因素做一综述。     

成骨不全症治疗新药研究进展

成骨不全症是以骨骼脆性增加、反复骨折为主要临床表现的遗传性骨病,属于诊断及治疗均面临挑战的罕见病,目前尚缺乏有效的针对病因的治疗策略.近年来研究显示双膦酸盐,甲状旁腺素氨基端片段,针对核因子KB受体活化因子配体、骨硬化素和转化生长因子-B等的单克隆抗体药物,有望增加骨密度、改善骨骼微结构且降低骨折风险.本文综述成骨不全症的治疗新药研究进展.     

Noninvasive Quantitative Assessment of Bone Healing After Distraction Osteogenesis

One of the greatest challenges of limb lengthening and deformity correction is deciding when the bone has healed enough to remove the external fixator. Standard radiography is the most common imaging method used to assess bone healing after distraction osteogenesis because it is widely available, cheap, and relatively safe. However, other imaging technologies and methods are being investigated that will help quantify bone healing after distraction osteogenesis, providing an objective method for deciding when it is appropriate to remove an external fixator. This review will examine the latest techniques used to assess bone healing after distraction osteogenesis including dual-energy X-ray absorptiometry scans, ultrasound, quantitative computed tomography, and digital radiography (X-ray). Recommendations for clinical practice will be outlined.     

微包囊优化制备及复合自体微小颗粒骨异位成骨的实验研究

目的探讨优化生长因子微包囊制作方法,观察其释放规律和复合微小颗粒骨异位成骨的效果。方法正交设计优化聚乳酸-羟基乙酸共聚物(poly-DL-lactide-co-glycolide,PLGA)微包囊制作工艺,于2、4、8、12、24、36、48、60、72、84、96、120、144、168、192、216、240和264h计算微包囊的累计释放量。实验取24只Wistar大鼠,随机分为4组(n=6),每只大鼠于双侧股部作1cm切口,制备臀大肌肌袋模型。A组双侧植入胶原,B组双侧植入胶原和颗粒骨,C组双侧植入胶原和重组人骨形成蛋白2(recombinant human bone morphogenetic protein2,rhBMP-2)/PLGA缓释微包囊;D组双侧植入胶原、颗粒骨与rhBMP-2/PLGA缓释微包囊。于术后3、4和5周取样(n=2)行大体和组织学观察。结果各优化变量对微包囊粒径及其包封率均有影响,包囊表面光滑,成球较好。体外能够在11d内缓慢释放。术后3周大体观察,A组未触及移植物,B、C、D组可触及,微包囊呈白色颗粒包裹于组织中。组织学观察:术后3周,A组胶原已经完全吸收,其余3组可见残余胶原;术后4周,A组胶原已不易见到,B组可见微小颗粒骨继续吸收,体积变小;C组包囊体积缩小,囊间成骨性细胞增多;D组微小颗粒骨和微包囊继续吸收,成骨性细胞和软骨性细胞团增多;术后5周,B、C、D组均可见植入物体积减小,包囊被吸收破碎,但颗粒骨和包囊周围的软骨性细胞、成骨性细胞更加密集。结论优化PLGA微包囊制备工艺,使其在体外能够长时间缓释。自体微小颗粒骨可在臀大肌肌袋内异位诱导生成大量成骨性细胞,PLGA微包囊可以与其有机复合,并在减少生长因子用量的同时协同微小颗粒骨成骨。     

比较带蒂筋膜瓣包裹接种自体红骨髓的组织工程骨修复骨缺损时促血管化成骨与膜诱导成骨作用

目的比较带蒂筋膜瓣包裹组织工程骨在修复骨缺损时促血管化成骨与膜诱导成骨的作用,为临床修复骨缺损提供参考依据。方法采用兔自体红骨髓(autologous red bone marrow,ARBM)及含重组人BMP-2的骨诱导活性材料构建组织工程骨。将4～5月龄新西兰大白兔60只(体重2.0～2.5 kg),随机分为A、B、C 3组,A组16只,B、C组各22只。制备长1.5 cm的右尺骨长段骨-骨膜完全缺损模型,A组于骨缺损处植入组织工程骨;B、C组在骨缺损邻近处制备一筋膜瓣包裹组织工程骨后植入骨缺损,B组将筋膜瓣蒂部切断形成游离筋膜瓣,C组为带蒂筋膜瓣。术后4、8、12、16周,每组随机取4只实验动物,取骨缺损区组织进行大体观察、组织学及免疫组织化学染色观察;8、12、16周B、C组各另取2只实验动物行腋动脉墨汁灌注观察。结果大体观察示,术后4、8周A组有纤维结缔组织形成,B、C组筋膜瓣形成类似骨膜样纤维组织,其中B组有软骨样组织形成,C组有新生骨形成;12、16周A组骨痂形成少,B组新生骨较多,C组骨干形成。组织学观察示,术后4、8周A、B组新生血管和骨小梁极少,C组血管丰富且成熟骨小梁及软骨组织形成;12、16周A组新生血管及骨小梁仍较少,B组血管数量较多且成熟骨小梁显著增加,髓腔结构形成但闭阻;C组血管数量减少,成熟骨结构形成,骨髓腔再通。免疫组织化学染色示,C组各时间点CD105、CD34、Ⅷ因子表达均高于A、B组。骨形态计量分析显示,术后各时间点C组新生骨小梁体积明显大于A、B组(P<0.05);A、B组间除4周差异无统计学意义(P>0.05)外,其余时间点差异均有统计学意义(P<0.05)。血管图像分析显示术后各时间点C组骨修复区内血管再生面积比值明显大于A、B组(P<0.05)。墨汁灌注检查示,各时间点B组成骨区为稀疏的墨染区;C组成骨区墨染数量多且较密集,8周达高峰,之后逐渐减少。结论 带蒂筋膜瓣包裹复合自体ARBM的组织工程骨,早期以促血管化成骨作用占主导地位,后期血管化成骨作用逐渐消失,以膜诱导成骨作用为主。     

体外负压培养对hBMSCs成骨活性影响的初步研究

[目的]探讨体外负压培养对hBMSCs成骨活性的影响.[方法]取第3代hBMSCs分为实验组和对照组,实验组进行间歇性负压培养,设置压力为17 kPa,30 min/次,4次/d,干预2周;对照组于普通CO,培养箱中常规培养.倒置显微镜下观察细胞形态,MTT法和流式细胞仪检测细胞增殖和凋亡,检测ALP活性,茜素红染色观察钙节结形成,免疫组织化学检测Ⅰ型胶原和VEGF的表达.[结果]诱导2周,实验组细胞增殖能力下降,S期细胞百分比为(5.14±1.56)%,较对照组(13.45±3.51)%约下降62.4%,细胞凋亡增加.实验组ALP活性为(15.68±1.97)mU/mg,对照组为(6.344±1.21)mU/mg,两组比较差异有统计学意义(P<0.05);与对照组比较,实验组钙结节形成增多,VEGF表达较对照组显著提高;实验组Ⅰ型胶原表达呈阳性,对照组呈阴性反应.[结论]负压能抑制hBMSCs增殖,促进细胞凋亡,但可以提高细胞成骨活性.     

Osteoclast depletion with clodronate liposomes delays fracture healing in mice

Osteoclasts are abundant within the fracture callus and also localize at the chondro‐osseous junction. However, osteoclast functions during fracture healing are not well defined. Inhibition of osteoclast formation or resorptive activity impairs callus remodeling but does not prevent callus formation. Interestingly, though anti‐osteoclast therapies differentially affect resolution of callus cartilage into bone. Treatments that inhibit osteoclast formation or viability tend to impair callus cartilage resolution, while treatments that target inhibition of bone resorption generally do not affect callus cartilage resolution. Here, we tested whether depletion of osteoclasts by systemic treatment with clodronate liposomes would similarly impair callus cartilage resolution. ICR mice were treated by intraperitoneal injections of clodronate‐laden liposomes or control liposomes and subjected to closed femur fracture. Femurs were resected at multiple times after fracture and analyzed by radiography, histology, and mechanical testing to determine effects on healing. Clodronate liposome treatment did not prevent callus formation. However, radiographic scoring indicated that clodronate liposome treatment impaired healing. Clodronate liposome treatment significantly reduced callus osteoclast populations and delayed resolution of callus cartilage. Consistent with continued presence of callus cartilage, torsional mechanical testing found significant decreases in callus material properties after 28 days of healing. The results support a role for osteoclasts in the resolution of callus cartilage into bone. Whether the cartilage resolution role for osteoclasts is limited to simply resorbing cartilage at the chondro‐osseous junction or in promoting bone formation at the chondro‐osseous junction through another mechanism, perhaps similar to the reversal process in bone remodeling, will require further experimentation. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1699–1706, 2017.

     

幼龄犬的上颌骨延长

目的 探讨利用牵开成骨技术在幼儿发育期对发育不良的上颌骨进行诱导外科正颌的可能性,牵开成骨是否有碍幼儿上颌骨的继续生长发育。方法 4－6月龄杂种犬13只,行一侧上颌前部根尖下截骨,外置延长器固定,于1周后,按0．5－1mm/d的速度用延长装置牵开,牵开至10－20mm时,固定4－6周,卸下延长器,于术日,牵开前,牵开期间,固定期间定期摄X线片,分批处死动物,行咬合关系变化,三维立体测量及组织学等观察,结果 术侧有确切的延长效果,咬合关系发生变化,延长段经膜内成骨逐渐演谈正常骨组织,术侧的上颌骨除延长段外,生长发育基本与未术侧同步。结论 于颅面生长发育期的幼龄犬行 开成骨,进行诱导外科正颌治疗是有效的,且不致影响其继续生长发育。