Division of Craniofacial Function Engineering, Tohoku University Graduate of Dentistry, Sendai, Japan.
Biomed Mater. 2012 Aug;7(4):045020. doi: 10.1088/1748-6041/7/4/045020. Epub 2012 Jun 28.
The present study was designed to investigate the extent to which calcium phosphate bone substitute materials, including osteoconductive octacalcium phosphate (OCP), display cytotoxic and inflammatory responses based on their dissolution in vitro. Hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) ceramics, which are clinically used, as well as dicalcium phosphate dihydrate (DCPD) and synthesized OCP were compared. The materials were well characterized by chemical analysis, x-ray diffraction and Fourier transform infrared spectroscopy. Calcium and phosphate ion concentrations and the pH of culture media after immersion of the materials were determined. The colony forming rate of Chinese hamster lung fibroblasts was estimated with extraction of the materials. Proliferation of bone marrow stromal ST-2 cells and inflammatory cytokine TNF-α production by THP-1 cells grown on the material-coated plates were examined. The materials had characteristics that corresponded to those reported. DCPD was shown to dissolve the most in the culture media, with a marked increase in phosphate ion concentration and a reduction in pH. ST-2 cells proliferated well on the materials, with the exception of DCPD, which markedly inhibited cellular growth. The colony forming capacity was the lowest on DCPD, while that of the other calcium phosphates was not altered. In contrast, TNF-α was not detected even in cells grown on DCPD, suggesting that calcium phosphate materials are essentially non-inflammatory, while the solubility of the materials can affect osteoblastic and fibroblastic cellular attachment. These results indicate that OCP is biocompatible, which is similar to the materials used clinically, such as HA. Therefore, OCP could be clinically used as a biocompatible bone substitute material.
本研究旨在探讨磷酸钙骨替代材料（包括具有骨诱导性的八钙磷酸钙[OCP]）在体外溶解时的细胞毒性和炎症反应程度。比较了临床上使用的羟基磷灰石（HA）和β-磷酸三钙（β-TCP）陶瓷，以及二水磷酸二钙（DCPD）和合成的 OCP。通过化学分析、X 射线衍射和傅里叶变换红外光谱对材料进行了很好的表征。测定了材料浸提后培养基中钙离子和磷酸根离子浓度以及 pH 值。通过提取材料，评估了中国仓鼠肺成纤维细胞的集落形成率。检测了在材料涂覆的平板上生长的骨髓基质 ST-2 细胞的增殖和 THP-1 细胞产生的炎性细胞因子 TNF-α。材料具有与报道相符的特性。DCPD 在培养基中溶解最多，磷酸根离子浓度显著增加，pH 值降低。除 DCPD 外，ST-2 细胞在材料上生长良好，DCPD 明显抑制细胞生长。DCPD 上的集落形成能力最低，而其他磷酸钙则没有改变。相比之下，即使在 DCPD 上生长的细胞中也未检测到 TNF-α，表明磷酸钙材料基本无炎症，而材料的溶解度会影响成骨细胞和成纤维细胞的附着。这些结果表明 OCP 具有生物相容性，与临床上使用的材料（如 HA）相似。因此，OCP 可作为一种具有生物相容性的骨替代材料在临床上使用。
