PHYSIOLOGICAL CONCENTRATIONS OF GLUCOCORTICOIDS STIMULATE FORMATION OF BONE NODULES FROM ISOLATED RAT CALVARIA CELLS-INVITRO
PHYSIOLOGICAL CONCENTRATIONS OF GLUCOCORTICOIDS STIMULATE FORMATION OF BONE NODULES FROM ISOLATED RAT CALVARIA CELLS-INVITRO
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DOI：
10.1210/endo-121-6-1985
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发表时间：
1987-12-01
期刊：
影响因子：
4.8
通讯作者：
HEERSCHE, JNM
中科院分区：
文献类型：
--
作者：
BELLOWS, CG;AUBIN, JE;HEERSCHE, JNM
将分离的大鼠颅骨细胞以低密度接种在补充有抗坏血酸和有机磷酸盐的培养基中，形成具有骨特征的离散的三维矿化结节。我们研究了糖皮质激素对这些细胞群形成骨结节的影响。从21日龄胎鼠颅骨分离的细胞在体外维持长达27天。地塞米松（Dex）诱导形成的结节数量呈剂量相关性增加，峰值为10 nM，半数最大反应约为1 nM。Dex（10 nM）也显著增加形成的骨结节的大小（P < 0.002）。高浓度的Dex（1 μ M）不增加根瘤数。在维持在含有10 nM Dex的培养基中的原代培养物中的细胞中，结节数量的增加比对照值高50-100%。Dex的作用在第一次传代细胞中大得多，其中结节的数量比对照值高600-800%。从12-27天收集并定量的培养皿显示，在没有Dex的培养物中，结节形成在15至18天之间停止，而在Dex存在下，结节的数量增加至27天。仅在特定时期添加10 nM Dex导致比对照培养物中显著更多的结节，但比持续暴露于Dex的培养物中显著更少的结节。对数生长期细胞群体倍增时间不变，但用10 nM Dex观察到饱和密度显著增加（P < 0.001）。氢化可的松还引起形成的结节数量增加，最大效应为50 nM，半最大反应为8 nM。结果表明，在长期细胞培养中，生理水平的糖皮质激素通过增加形成骨结节的细胞数量来刺激骨结节形成，并且糖皮质激素对骨形成的刺激作用的最大化可能需要持续暴露于低水平的激素。
Isolated rat calvaria cells plated at low density in medium supplemented with ascorbic acid and organic phosphate form discrete three-dimensional mineralized nodules having the characteristics of bone. We have studied the effects of glucocorticoids on the formation of bone nodules by these cell populations. Cells isolated from 21-day-old fetal rat calvaria were maintained in vitro for up to 27 days. Dexamethasone (Dex) induced a dose-related increase in the number of nodules formed, with a peak at 10 nM and a half-maximal response at about 1 nM. Dex (10 nM) also significantly increased the size of bone nodules formed (P < 0.002). High concentrations of Dex (1 .mu.M) did not increase nodule number. In cells in primary culture maintained in medium containing 10 nM Dex, the increase in nodule number was 50-100% over the control value. The effect of Dex was much greater in first subculture cells, where the number of nodules was 600-800% higher than the control value. Dishes collected and quantitated from 12-27 days showed that nodule formation ceased between 15 and 18 days in cultures without Dex, whereas in the presence of Dex the number of nodules increased up to 27 days. Addition of 10 nM Dex only during specific periods resulted in significantly more nodules than in control cultures, but significantly fewer nodules than in cultures constantly exposed to Dex. Cell population doubling times during log phase growth were unaltered, but a significant increase in saturation density (P < 0.001) was observed with 10 nM Dex. Hydrocortisone also caused an increase in the number of nodules formed, with a maximal effect of 50 nM and a half-maximal response at 8 nM. The results indicate that physiological levels of glucocorticoids stimulate bone nodule formation in long term cell culture by increasing the number of cells forming bone nodules and that maximization of the stimulatory effect of glucocorticoids on bone formation may require constant exposure to low levels of the hormone.