Hanagata Nobutaka, Takemura Taro, Monkawa Akira, Ikoma Toshiyuki, Tanaka Junzo
Biomaterials Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
J Biomed Mater Res A. 2007 Nov;83(2):362-71. doi: 10.1002/jbm.a.31240.
Hydroxyapatite and type-I collagen are major components of bone matrix. We compared phenotype and gene expression pattern of osteoblast-like cells cultured on HAp and HAp with pre-adsorbed type-I collagen from neutral solutions (HAp/NCs) with those of tissue culture grade polystyrene (TCPS) and TCPS with the collagen (TCPS/NCs). In initial cell attachment, the cells tensely spread on TCPS, while loosely spread on TCPS/NCs, HAp, and HAp/NCs. The levels of expressed integrin alpha2 and alpha5 subunits were not significantly different among any surfaces. Although the cells on HAp/NCs directly attached with the same collagen molecules as TCPS/NCs, mineralization was observed in only TCPS/NCs. The basal substrates (TCPS and HAp) greatly influenced osteoblast maturation even in the surfaces with pre-adsorbed collagen, since mineralization was induced by TCPS, but not by HAp. Gene expression pattern analyzed with DNA microarray also supported greater influence of basal substrates than pre-adsorbed collagen. In addition, comprehensive gene expression analyses revealed that HAp and HAp/NCs specifically up-regulated Ly6a and Tmem37 genes, while down-regulated Ifitm5 gene.
羟基磷灰石和I型胶原蛋白是骨基质的主要成分。我们比较了在羟基磷灰石（HAp）、预先从中性溶液中吸附了I型胶原蛋白的HAp（HAp/NCs）上培养的成骨样细胞与组织培养级聚苯乙烯（TCPS）以及吸附了胶原蛋白的TCPS（TCPS/NCs）上培养的成骨样细胞的表型和基因表达模式。在初始细胞附着过程中，细胞在TCPS上紧密铺展，而在TCPS/NCs、HAp和HAp/NCs上则松散铺展。在任何表面上，整合素α2和α5亚基的表达水平均无显著差异。尽管HAp/NCs上的细胞与TCPS/NCs上的细胞直接附着的胶原蛋白分子相同，但仅在TCPS/NCs上观察到矿化现象。即使在预先吸附了胶原蛋白的表面，基础底物（TCPS和HAp）对成骨细胞成熟也有很大影响，因为TCPS能诱导矿化，而HAp则不能。用DNA微阵列分析的基因表达模式也支持基础底物比预先吸附的胶原蛋白影响更大。此外，综合基因表达分析表明，HAp和HAp/NCs特异性上调Ly6a和Tmem37基因，而下调Ifitm5基因。
