Aronow M A, Gerstenfeld L C, Owen T A, Tassinari M S, Stein G S, Lian J B
Department of Cell Biology, University of Massachusetts Medical School, Worcester 01655.
J Cell Physiol. 1990 May;143(2):213-21. doi: 10.1002/jcp.1041430203.
Rat calvaria osteoblasts derived from 21-day-old fetal rat pups undergo a temporal expression of markers of the osteoblast phenotype during a 5 week culture period. Alkaline phosphatase and osteocalcin are sequentially expressed in relation to collagen accumulation and mineralization. This pattern of expression of these osteoblast parameters in cultured rat osteoblasts (ROB) is analogous to that seen in vivo in developing fetal rat calvaria tissue (Yoon et. al: Biochem. Biophis. Res. Commun. 148:1129, 1987) and is similar to that observed in cultures of subcultivated 16-day-old embryonic chick calvaria-derived osteoblasts (COB) (Gerstenfeld, et.al: Dev. Biol. 122:46, 1987). While the cellular organization of subcultivated COB and primary ROB cultures are somewhat different, the temporal expression of the parameters remains. Both the rat and chick culture systems support formation of matrix mineralization even in the absence of beta-glycerol-phosphate. A systematic examination of factors which constitute conditions supporting complete expression of the osteoblast phenotype in ROB cultures indicate requirements for specific serum lots, ascorbic acid and the ordered deposition of mineral in the extracellular matrix. The present studies suggest that formation of a collagenous matrix, dependent on ascorbic acid, is requisite for expression of the osteoblast phenotype. In ROB cultures, expression of osteocalcin synthesis occurs subsequent to initiation of alkaline phosphatase activity and accompanies the formation of mineralized nodules. Thus, extracellular matrix mineralization (deposition of hydroxyapatite) is required for complete development of the osteoblast phenotype, as reflected by a 200-fold increase in osteocalcin synthesis. These data show the temporal expression of the various osteoblast parameters during the formation and mineralization of an extracellular matrix can provide markers reflective of various stages of osteoblast differentiation/maturation in vitro.
源自21日龄胎鼠幼崽的大鼠颅骨成骨细胞在5周的培养期内经历成骨细胞表型标志物的阶段性表达。碱性磷酸酶和骨钙素的表达与胶原蛋白积累和矿化顺序相关。这些成骨细胞参数在培养的大鼠成骨细胞（ROB）中的表达模式类似于在发育中的胎鼠颅骨组织中体内观察到的模式（Yoon等人：《生物化学与生物物理学研究通讯》148:1129，1987），并且与在传代培养的16日龄胚胎鸡颅骨来源的成骨细胞（COB）培养物中观察到的模式相似（Gerstenfeld等人：《发育生物学》122:46，1987）。虽然传代培养的COB和原代ROB培养物的细胞组织有所不同，但这些参数的阶段性表达仍然存在。大鼠和鸡的培养系统即使在没有β-甘油磷酸的情况下也支持基质矿化的形成。对构成支持ROB培养物中成骨细胞表型完全表达条件的因素进行系统检查表明，需要特定批次的血清、抗坏血酸以及矿物质在细胞外基质中的有序沉积。目前的研究表明，依赖抗坏血酸的胶原基质的形成是成骨细胞表型表达所必需的。在ROB培养物中，骨钙素合成的表达在碱性磷酸酶活性开始后发生，并伴随着矿化结节的形成。因此，细胞外基质矿化（羟基磷灰石的沉积）是成骨细胞表型完全发育所必需的，这表现为骨钙素合成增加200倍。这些数据表明，在细胞外基质形成和矿化过程中各种成骨细胞参数的阶段性表达可以提供反映体外成骨细胞分化/成熟各个阶段的标志物。
