Kotev-Emeth S, Savion N, Pri-chen S, Pitaru S
Maurice and Gabriela Goldschleger Eye Research Institute, Maurice and Gabriela Goldschleger School of Dental Medicine, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Bone. 2000 Dec;27(6):777-83. doi: 10.1016/s8756-3282(00)00389-6.
Formation of bone-like tissue in culture by stromal bone marrow cells (SBMC) derived from young growing rats is dependent on dexamethasone (Dex) (Cell Tissue Res 254:317; 1988) and is significantly enhanced by basic fibroblast growth factor (bFGF) (J Bone Miner Res 8:919; 1993). The aim of this study was to examine the effect of maturation on the osteogenic potential and the response to Dex and bFGF of SBMC by using cultures derived from young growing (6 weeks old) and adult (9 months old) rats. SBMC cultures were grown in the presence of Dex (10(-8) or 10(-7) mol/L) at both P(0) and P(1) and either in the presence or absence of bFGF. The effect of Dex and bFGF on mineralized bone-like tissue (MBT) formation was assessed at P(1). The highest levels of mineralized tissue formation in P(1) subcultures in the absence of bFGF were obtained when cultures derived from young rats (6 weeks old) were treated with Dex 10(-7) and 10(-8) mol/L at P(0) and P(1), respectively, and when cultures derived from adult rats were exposed to Dex 10(-8) mol/L both at P(0) and P(1). Under these optimal Dex concentrations, the amount of MBT formed by adult rat-derived cultures was 15-fold lower than that of young rat-derived ones. The addition of bFGF to P(0) cultures or to P(1) cultures grown under optimal Dex conditions enhanced MBT formation in P(1) cultures derived from both young and adult rats, but this effect was considerably more pronounced in the adult rat-derived cultures. The maximal levels of MBT formation were produced by cultures derived from adult rats treated with bFGF at both P(0) and P(1), whereas in cultures derived from young rats, the addition of bFGF at P(0) was not necessary for maximal MBT production. This stimulating effect of bFGF on MBT formation by adult rat-derived cultures was accompanied by a 2.2-, 1.8-, and 4.3-fold increase in proliferation, alkaline phosphatase activity, and Ca(2+) deposition rate, respectively. bFGF increased the level of glucocorticoid receptor by approximately 2. 3-fold in Dex-treated cultures derived from young animals. These results indicate that maturation is associated with a decrease in the proportion of osteoprogenitor cells in the stromal bone marrow and in their capacity to express the osteogenic phenotype. They further point to the significant role of bFGF in stimulating proliferation and osteogenic expression of stromal bone marrow osteoprogenitors derived from adult rats.
来自幼年生长大鼠的基质骨髓细胞（SBMC）在培养中形成类骨组织依赖于地塞米松（Dex）（《细胞与组织研究》254:317；1988年），并且碱性成纤维细胞生长因子（bFGF）可显著增强其形成（《骨与矿物质研究杂志》8:919；1993年）。本研究的目的是通过使用来自幼年生长（6周龄）和成年（9月龄）大鼠的培养物，研究成熟对SBMC成骨潜能以及对Dex和bFGF反应的影响。SBMC培养物在P(0)和P(1)时均在Dex（10(-8)或10(-7) mol/L）存在的情况下生长，且分别在有或无bFGF的情况下培养。在P(1)时评估Dex和bFGF对矿化类骨组织（MBT）形成的影响。在无bFGF的情况下，P(1)传代培养物中矿化组织形成的最高水平，是当来自幼年大鼠（6周龄）的培养物在P(0)和P(1)时分别用10(-7)和10(-8) mol/L的Dex处理时，以及当来自成年大鼠的培养物在P(0)和P(1)时均暴露于10(-8) mol/L的Dex时获得的。在这些最佳Dex浓度下，成年大鼠来源的培养物形成的MBT量比幼年大鼠来源的低15倍。在最佳Dex条件下生长的P(0)培养物或P(1)培养物中添加bFGF，可增强来自幼年和成年大鼠的P(1)培养物中MBT的形成，但这种作用在成年大鼠来源的培养物中更为明显。MBT形成的最高水平是由在P(0)和P(1)时均用bFGF处理的成年大鼠来源的培养物产生的，而在幼年大鼠来源的培养物中，在P(0)时添加bFGF对于最大MBT产生并非必需。bFGF对成年大鼠来源的培养物中MBT形成的这种刺激作用分别伴随着增殖、碱性磷酸酶活性和Ca(2+)沉积率增加2.2倍、1.8倍和4.3倍。在来自幼年动物的Dex处理培养物中，bFGF使糖皮质激素受体水平增加约2.3倍。这些结果表明，成熟与基质骨髓中骨祖细胞比例及其表达成骨表型的能力下降有关。它们进一步指出bFGF在刺激成年大鼠来源的基质骨髓骨祖细胞增殖和成骨表达方面的重要作用。
