The Effect of Microstructure of Octacalcium Phosphate on the Bone Regenerative Property
The Effect of Microstructure of Octacalcium Phosphate on the Bone Regenerative Property
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DOI：
10.1089/ten.tea.2008.0300
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发表时间：
2009-08-01
影响因子：
4.1
通讯作者：
Suzuki, Osamu
中科院分区：
文献类型：
--
作者：
Honda, Yoshitomo;Anada, Takahisa;Suzuki, Osamu
本研究旨在研究合成磷酸八钙（OCP）的微观结构是否影响其作为支架的内在骨再生特性及其转化为羟基磷灰石（HA）的过程。我们之前的研究表明，由随机取向的板状晶体组成的 OCP 晶体聚集体能够增强体外成骨细胞分化和骨再生。虽然OCP向HA的转化被认为与OCP在骨再生中的刺激能力有关，但对于OCP颗粒的微观结构对这些能力的影响知之甚少。制备了两种类型的 OCP 颗粒，它们具有相同的直径（300-500 μm），但由具有不同晶体尺寸（4.0 和 26.6 μm 长度）的晶体组成（以下分别称为细 OCP 颗粒 [F-OCP] 和粗 OCP 颗粒 [C-OCP]）。通过压汞估算，F-OCP 的粒间距离和孔隙率（包括粒间空间）为 108.5 mm 和 93.7%，C-OCP 为 67.5 mm 和 95.7%。 OCP 颗粒被植入小鼠临界大小的颅骨缺损中长达 14 天。组织学检查表明，第 7 天，成骨细胞在 F-OCP 表面排列，并在颗粒周围形成新骨，直至第 14 天。另一方面，C-OCP 周围的细胞在第 7 天稀疏，导致第 14 天颗粒周围仅形成轻微的骨形成。X 射线衍射显示，两种 OCP 颗粒在植入后倾向于以相似的转化速度转化为磷灰石结构。体外实验中，与 F-OCP 相比，C-OCP 显着抑制小鼠骨髓基质 ST-2 细胞的粘附。这些结果表明，由 OCP 板状晶体组成的微观结构控制着晶体表面上的细胞粘附及其由此产生的骨再生特性，以及与先前报道的 OCP 短暂性质相关的物理化学效应。
The present study was designed to investigate whether the microstructure of synthetic octacalcium phosphate (OCP) affects its intrinsic bone regenerative properties as a scaffold and its conversion process into hydroxyapatite (HA). Our previous studies indicated that an agregate of OCP crystals, consisting of randomly oriented plate-like crystals, are capable of enhancing both osteoblastic cell differentiation in vitro and bone regeneration. While the transformation of OCP into HA has been considered in relation to the stimulatory capacity of OCP in bone regeneration, little is known about the effect of the microstructure of OCP granules on these capabilities. Two types of OCP granules, with identical diameters (300-500 mu m) but composed of crystals with distinct crystal dimensions (4.0 and 26.6 mu m length), were prepared (hereafter referred to as fine OCP granules [F-OCP] and coarse OCP granules [C-OCP], respectively). The intergranule distances and the porosity, including the intergranule spaces, were 108.5 mm and 93.7% for F-OCP, and 67.5 mm and 95.7% for C-OCP, as estimated by mercury intrusion. The OCP granules were implanted in mouse critical-sized calvarial defects for up to 14 days. Histological examination demonstrated that osteoblastic cells aligned on the surface of F-OCP at day 7 and formed new bone around the granules up to day 14. On the other hand, cells around C-OCP were sparse at day 7, and resulted in only slight bone formation around the granules at day 14. X-ray diffraction showed that both OCP granules tended to be converted to an apatite structure with similar conversion velocity by the implantation. Adhesion of mouse bone marrow stromal ST-2 cells was markedly inhibited on C-OCP compared to F-OCP in vitro. These results suggested that the microstructure consisting of plate-like crystals of OCP controls cell adhesion on the crystal surfaces and their resultant bone regenerative properties as well as the physicochemical effect associated with the transitory nature of OCP previously reported.