Dong J, Kojima H, Uemura T, Kikuchi M, Tateishi T, Tanaka J
Tissue Engineering Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 4, Tsukuba, Ibaraki 305-8562, Japan.
J Biomed Mater Res. 2001 Nov;57(2):208-16. doi: 10.1002/1097-4636(200111)57:2<208::aid-jbm1160>3.0.co;2-n.
Biosynthetic bone grafts are considered to contain one or more of three critical components: osteoprogenitor cells, an osteoconductive matrix, and osteoinductive growth factors. The basic requirements of the scaffold material are biocompatibility, mechanical integrity, and osteoconductivity. A major design problem is satisfying these requirements with a single composite. In this study, we hypothesize that one composite that combines bone marrow-derived osteoblasts and a novel mechanical reinforced porous hydroxyapatite with good biocompatibility and osteoconductivity (HA/BMO) can reach these requirements. A novel sintered porous hydroxyapatite (HA) was prepared by the following procedures. The HA slurry was foamed by adding polyoxyethylenelaurylether (PEI) and mixing. The pores were fixed by crosslinking PEI with diepoxy compounds and the HA porous body was sintered at 1200 degrees C for 3 h. The HA sintered porous body had a high porosity (77%), and was completely interconnected. Average pore diameter was 500 microm and the interconnecting path 200 microm in diameter. The compressive (17 MPa) and three-point bending (7 MPa) strengths were high. For in vivo testing, the 2-week subcultured HA/BMO (+) composites were implanted into subcutaneous sites of syngeneic rats until 8 weeks after implantation. These implants were harvested at different time points and prepared for the biochemical analysis of alkaline phosphatase activity (ALP) and bone osteocalcin content (OCN), and histological analysis. ALP and OCN in the HA/BMO group were much higher than those in the HA without BMOs control group 1 week after implantation (p < 0.001). Light microscopy revealed mature bone formation in the HA/BMO composite 4 weeks after implantation. In the SEM study, mineralized collagenous extracellular matrix was noted in HA/BMO composite 2 weeks after implantation with numbers of active osteoblasts. We conclude that the composite of the novel HA and cultured BMOs has osteogenic ability in vivo. These results provide a basis for further studies on the use of this composite as an implant in orthopaedic surgery.
骨祖细胞、骨传导基质和骨诱导生长因子。支架材料的基本要求是生物相容性、机械完整性和骨传导性。一个主要的设计问题是用单一复合材料满足这些要求。在本研究中，我们假设一种将骨髓来源的成骨细胞与具有良好生物相容性和骨传导性的新型机械增强多孔羟基磷灰石（HA/BMO）相结合的复合材料能够满足这些要求。通过以下步骤制备了一种新型烧结多孔羟基磷灰石（HA）。通过添加聚氧乙烯月桂醚（PEI）并混合使HA浆料发泡。通过将PEI与二环氧化合物交联固定孔隙，并将HA多孔体在1200℃下烧结3小时。HA烧结多孔体具有高孔隙率（77%），且完全相互连通。平均孔径为500微米，连通路径直径为200微米。抗压强度（17MPa）和三点弯曲强度（7MPa）较高。为了进行体内测试，将传代培养2周的HA/BMO（+）复合材料植入同基因大鼠的皮下部位，直至植入后8周。在不同时间点采集这些植入物，准备进行碱性磷酸酶活性（ALP）和骨钙素含量（OCN）的生化分析以及组织学分析。植入后1周，HA/BMO组的ALP和OCN远高于无BMOs的HA对照组（p<0.001）。光学显微镜显示植入后4周HA/BMO复合材料中有成熟的骨形成。在扫描电子显微镜研究中，植入后2周在HA/BMO复合材料中观察到矿化的胶原细胞外基质以及大量活跃的成骨细胞。我们得出结论，新型HA与培养的BMOs的复合材料在体内具有成骨能力。这些结果为进一步研究将该复合材料用作骨科手术植入物提供了依据。
