Abstract：
A biphasic calcium phosphate with submicron needle-shaped surface topography combined with a novel polyethylene glycol/polylactic acid triblock copolymer binder (BCP-EP) was investigated in this study. This study aims to evaluate the composition, degradation mechanism and bioactivity of BCP-EP in vitro, and its in vivo performance as an autograft bone graft (ABG) extender in a rabbit Posterolateral Fusion (PLF) model. The characterization of BCP-EP and its in vitro degradation products showed that the binder hydrolyses rapidly into lactic acid, lactide oligomers and unaltered PEG (polyethylene glycol) without altering the BCP granules and their characteristic submicron needle-shaped surface topography. The bioactivity of BCP-EP after immersion in SBF revealed a progressive surface mineralization. In vivo, BCP-EP was assessed in a rabbit PLF model by radiography, manual palpation, histology and histomorphometry up to 12 weeks post-implantation. Twenty skeletally mature New Zealand (NZ) White Rabbits underwent single-level intertransverse process PLF surgery at L4/5 using (1) autologous bone graft (ABG) alone or (2) by mixing in a 1:1 ratio with BCP-EP (BCP-EP/ABG). After 3 days of implantation, histology showed the BCP granules were in direct contact with tissues and cells. After 12 weeks, material resorption and mature bone formation were observed, which resulted in solid fusion between the two transverse processes, following all assessment methods. BCP-EP/ABG showed comparable fusion rates with ABG at 12 weeks, and no graft migration or adverse reaction were noted at the implantation site nor in distant organs.
摘要：
在这项研究中，研究了具有亚微米针状表面形貌的双相磷酸钙与新型聚乙二醇/聚乳酸三嵌段共聚物粘合剂（BCP-EP）的结合。本研究旨在评估成分，BCP-EP的体外降解机理及生物活性,及其在兔后外侧融合（PLF）模型中作为自体移植骨（ABG）延伸剂的体内性能。BCP-EP及其体外降解产物的表征表明，该粘合剂快速水解为乳酸，丙交酯低聚物和未改变的PEG（聚乙二醇），而不改变BCP颗粒及其特征亚微米针状表面形貌。BCP-EP浸入SBF后的生物活性显示出渐进的表面矿化。在体内,BCP-EP在兔PLF模型中通过射线照相术评估，手工触诊,植入后12周的组织学和组织形态计量学。20只骨骼成熟的新西兰（NZ）白兔在L4/5时使用（1）单独的自体骨移植物（ABG）或（2）以1：1的比例与BCP-EP（BCP-EP/ABG）混合进行了单水平横突间PLF手术。植入3天后，组织学显示BCP颗粒与组织和细胞直接接触。12周后,观察到材料吸收和成熟骨形成，这导致了两个横向过程之间的固体融合，遵循所有评估方法。BCP-EP/ABG在12周时表现出与ABG相当的融合率，在植入部位或远处器官均未发现移植物迁移或不良反应。
