El-Ghannam Ahmed, Cunningham Larry, Pienkowski David, Hart Amanda
Center for Biomedical Engineering and Center for Oral Health Research, College of Dentistry, University of Kentucky, Lexington, KY 40506, USA.
J Oral Maxillofac Surg. 2007 Aug;65(8):1495-502. doi: 10.1016/j.joms.2006.10.031.
The purpose of the present preliminary study is to show that a novel 3-dimensional porous silica-calcium phosphate nanocomposite (SCPC) can provide a controlled release of rhBMP-2 and regenerate bone in a load-bearing segmental defect.
A bone replica of the rabbit ulna was created from SCPC powder using rapid prototyping technology. The ceramic bone replica was coated with rhBMP-2 and then implanted into a 10-mm segmental defect created in a rabbit ulna and fixated with a 1-mm titanium adaptation plate. Bone healing was evaluated using computed tomography (CT) scan, histomorphometry, and biomechanical techniques. The release kinetics of rhBMP-2 and the dissolution kinetics were also determined in vitro. Statistical analysis was performed to compare the biomechanical strength of the grafted bone with the contralateral unoperated ulna.
After 4 weeks, CT scans showed that the critical size defect had been replaced by newly formed bone. Torsional testing of the ulna after 12 weeks showed restoration of maximum torque and angle at failure. Histological evaluation showed that the regenerated bone had the morphological characteristics of mature bone. SCPC provided a sustained release profile of an effective dose of rhBMP-2 for 14 days.
The SCPC-rhBMP-2 hybrid enhanced bone regeneration in a load-bearing segmental defect in a rabbit ulna. The regenerated bone acquired morphology and mechanical strength typical for natural bone. The enhanced bone formation correlates well with the surface bioactivity and effective release profile of rhBMP-2. The present preliminary study shows the proof of principles that porous, resorbable, bioactive SCPC-rhBMP-2 tissue engineering hybrid can serve as a substitute for autologous bone in load-bearing applications.
本初步研究的目的是表明一种新型的三维多孔二氧化硅 - 磷酸钙纳米复合材料（SCPC）能够实现重组人骨形态发生蛋白 -2（rhBMP -2）的控释，并在负重节段性骨缺损中促进骨再生。
使用快速成型技术由SCPC粉末制作兔尺骨的骨复制体。将陶瓷骨复制体用rhBMP -2包被，然后植入兔尺骨上制造的10毫米节段性骨缺损处，并用1毫米的钛适配板固定。使用计算机断层扫描（CT）、组织形态计量学和生物力学技术评估骨愈合情况。还在体外测定了rhBMP -2的释放动力学和溶解动力学。进行统计分析以比较移植骨与对侧未手术尺骨的生物力学强度。
4周后，CT扫描显示临界尺寸骨缺损已被新形成的骨替代。12周后对尺骨进行扭转测试显示最大扭矩和破坏时角度恢复。组织学评估表明再生骨具有成熟骨的形态特征。SCPC在14天内提供了有效剂量rhBMP -2的持续释放曲线。
SCPC - rhBMP -2复合物增强了兔尺骨负重节段性骨缺损处的骨再生。再生骨获得了天然骨典型的形态和机械强度。增强的骨形成与rhBMP -2的表面生物活性和有效释放曲线密切相关。本初步研究证明了多孔、可吸收、生物活性的SCPC - rhBMP -2组织工程复合物在负重应用中可替代自体骨的原理。
