Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China.
J Biomed Mater Res B Appl Biomater. 2011 Apr;97(1):10-9. doi: 10.1002/jbm.b.31773. Epub 2011 Feb 2.
Microstructure is indispensable for the osteoinduction of calcium phosphate ceramics. To study how microstructure takes its role and explore the mechanism of the osteoinduction, we evaluated attachment, proliferation, alkaline phosphatase (ALP)/DNA, protein/DNA, and mineralization of human adipose-derived stem cells cultured on two kinds of biphasic calcium phosphate (BCP) ceramic discs with the same chemistry and dimension, but different microporosity and surface area. BCP-A had been found osteoinductive in vivo while BCP-B was not. During the conventional culture, ALP/DNA and protein/DNA of the cell on BCP-A with larger surface area were significantly higher than those of the cells on BCP-B. With the adsorption of the proteins in culture medium with 50% fetal bovine serum (FBS) in advance, the increments of the ALP/DNA and protein/DNA for the BCP-A were found respectively significantly more than the increments of those for BCP-B, suggesting that the larger amount of protein adsorbed on the BCP-A was crucial. More results showed that ALP/DNA and protein/DNA of the cells on the two kinds of discs presoaked in culture medium having additional rhBMP-2 were found to be both higher than those of the cells on the discs resoaked in culture medium with 50% FBS, and that those values for BCP-A increased much more. Furthermore, larger mineral content was found on BCP-A than on BCP-B at day 7. The results indicated that by increasing microporosity and thus surface areas, osteoinductive calcium phosphate ceramics concentrate more proteins, including bone-inducing proteins, and thereafter stimulate inducible cells in soft tissues to form inductive bone.
微观结构对于磷酸钙陶瓷的成骨诱导作用是不可或缺的。为了研究微观结构如何发挥作用并探索成骨诱导的机制，我们评估了人脂肪来源干细胞在两种具有相同化学组成和尺寸但具有不同微孔率和比表面积的双相磷酸钙（BCP）陶瓷盘中的附着、增殖、碱性磷酸酶（ALP）/DNA、蛋白/DNA 和矿化。体内研究发现 BCP-A 具有成骨诱导性，而 BCP-B 则没有。在常规培养过程中，具有较大比表面积的 BCP-A 上细胞的 ALP/DNA 和蛋白/DNA 明显高于 BCP-B 上的细胞。通过预先用含有 50%胎牛血清（FBS）的培养基吸附蛋白质，发现 BCP-A 上的 ALP/DNA 和蛋白/DNA 的增加量明显高于 BCP-B 上的增加量，表明吸附在 BCP-A 上的蛋白质量更大。更多结果表明，两种类型的培养盘预先浸泡在含有 rhBMP-2 的培养基中，细胞的 ALP/DNA 和蛋白/DNA 均高于在含有 50%FBS 的培养基中重新浸泡的细胞，并且 BCP-A 上的值增加更多。此外，在第 7 天，BCP-A 上的矿化含量大于 BCP-B。结果表明，通过增加微孔率从而增加比表面积，成骨诱导性磷酸钙陶瓷浓缩更多的蛋白质，包括骨诱导蛋白，然后刺激软组织中的诱导细胞形成诱导性骨。
