Ishida H, Bellows C G, Aubin J E, Heersche J N
Department of Periodontology and Endotontology, School of Dentistry, Tokushima University, Japan.
Bone. 1995 May;16(5):545-9. doi: 10.1016/8756-3282(95)00102-j.
We investigated the role of 3,5,3'-tri-iodothyronine (T3) in regulating differentiation of osteoprogenitor cells and also studied the effects of the glucocorticoid hormone dexamethasone (Dex) on the T3-induced effects on osteoprogenitor populations. This was done by determining the effects of either hormone alone, or of combinations of the two hormones, on the number of bone nodules formed in long-term cultures of rat calvaria cells. In this system, Dex has been shown to increase bone nodule formation, the maximal effective dose being 10 nM (Bellows et al. Endocrinology 121: 1985-1992; 1987). In standard culture medium containing 15% fetal bovine serum FBS), low concentrations of T3 (0.001-0.1 nM) had no effect on the number of bone nodules, while higher concentrations of 1-100 nM inhibited. However, in culture medium containing 10 nM Dex, the lower concentrations of T3 markedly increased the number of nodules. Short term pulse experiments with these low concentrations of T3 in the presence of Dex indicated that stimulation of nodule formation occurred only when T3 was present prior to confluency. Higher concentrations of T3 (1-100 nM) decreased nodule number whether or not Dex was added. We then cultured cells in medium containing FBS from which T3 and T4 were removed by treatment with AG-1 chi-10 resin. In both + or - Dex conditions, bone nodule formulation was increased 1.5 to 2-fold in T3, T4-depleted medium when compared with cultures maintained in standard culture medium.(ABSTRACT TRUNCATED AT 250 WORDS)
我们研究了3,5,3'-三碘甲状腺原氨酸（T3）在调节骨祖细胞分化中的作用，并研究了糖皮质激素地塞米松（Dex）对T3诱导的骨祖细胞群体效应的影响。这是通过确定单独使用任何一种激素或两种激素组合对大鼠颅骨细胞长期培养中形成的骨结节数量的影响来完成的。在这个系统中，Dex已被证明能增加骨结节形成，最大有效剂量为10 nM（Bellows等人，《内分泌学》121:1985 - 1992；1987）。在含有15%胎牛血清（FBS）的标准培养基中，低浓度的T3（0.001 - 0.1 nM）对骨结节数量没有影响，而较高浓度的1 - 100 nM则有抑制作用。然而，在含有10 nM Dex的培养基中，较低浓度的T3显著增加了结节数量。在Dex存在的情况下，用这些低浓度的T3进行短期脉冲实验表明，只有当T3在汇合前存在时才会刺激结节形成。无论是否添加Dex，较高浓度的T3（1 - 100 nM）都会减少结节数量。然后，我们在含有经AG - 1 XAD - 10树脂处理去除T3和T4的FBS的培养基中培养细胞。与在标准培养基中培养的细胞相比，在+或 - Dex条件下，在T3、T4耗尽的培养基中骨结节形成增加了1.5至2倍。（摘要截断于250字）
