Huang Zhinong, Nelson Ehren Robert, Smith R Lane, Goodman Stuart B
Department of Orthopedic Surgery, Stanford University Medical Center, Stanford, California 94305, USA.
Tissue Eng. 2007 Sep;13(9):2311-20. doi: 10.1089/ten.2006.0423.
In this study, we delineate the sequential expression of selected growth factors associated with bone formation in vitro. Mineralization, osteocalcin, and alkaline phosphatase (ALP-2) were measured to monitor the differentiation and maturation of osteoprogenitor cells collected from C57BL mice. Bone-related growth factors, including transforming growth factor beta (TGF-beta), fibroblast growth factor 2 (FGF-2), platelet-derived growth factor (PDGF), insulinlike growth factor (IGF)-1, vascular endothelial growth factor (VEGF), bone morphogenetic protein (BMP)-2, and BMP-7, were selected. Enzyme-linked immunosorbent assay (ELISA) and reverse transcriptase polymerase chain reaction (RT-PCR) were used to measure growth factors at the protein and messenger ribonucleic acid (mRNA) level, respectively. The results found that ALP-2 expression increased progressively over time, whereas mineralization and osteocalcin did not become evident until culture day 14. VEGF and IGF-1 were upregulated early during proliferation. PDGF and TGF-beta mRNA expression was bimodal. FGF-2 and BMP-2 mRNAs were expressed only later in differentiation. FGF-2 mRNA signal levels were highest at day 14 and remained prominent through day 28 of culture. BMP-2 showed a similar profile as FGF-2. BMP-7 was not detectable using RT-PCR or ELISA. Strong correlations existed for the expression patterns between several early-response growth factors (VEGF, TGF-beta, and IGF-1) and were also evident for several late-response growth factors (BMP-2, PDGF, and FGF-2). Differential expression for grouped sets of growth factors occurs during the temporal acquisition of bone-specific markers as osteoprogenitor cell maturation proceeds in vitro.
在本研究中，我们描绘了体外与骨形成相关的特定生长因子的顺序表达。检测矿化、骨钙素和碱性磷酸酶（ALP-2）以监测从C57BL小鼠收集的骨祖细胞的分化和成熟。选择了与骨相关的生长因子，包括转化生长因子β（TGF-β）、成纤维细胞生长因子2（FGF-2）、血小板衍生生长因子（PDGF）、胰岛素样生长因子（IGF）-1、血管内皮生长因子（VEGF）、骨形态发生蛋白（BMP）-2和BMP-7。分别使用酶联免疫吸附测定（ELISA）和逆转录聚合酶链反应（RT-PCR）在蛋白质和信使核糖核酸（mRNA）水平检测生长因子。结果发现，ALP-2表达随时间逐渐增加，而矿化和骨钙素直到培养第14天才变得明显。VEGF和IGF-1在增殖早期上调。PDGF和TGF-β mRNA表达呈双峰。FGF-2和BMP-2 mRNA仅在分化后期表达。FGF-2 mRNA信号水平在第14天最高，并在培养第28天一直保持显著。BMP-2显示出与FGF-2相似的模式。使用RT-PCR或ELISA未检测到BMP-7。几种早期反应生长因子（VEGF、TGF-β和IGF-1）之间的表达模式存在强相关性，几种晚期反应生长因子（BMP-2、PDGF和FGF-2）之间也很明显。随着体外骨祖细胞成熟过程中骨特异性标志物的时间性获得，生长因子分组集的差异表达发生。
