IMMUNOGOLD LOCALIZATION OF BETA(1)-INTEGRIN IN BONE - EFFECT OF GLUCOCORTICOIDS AND INSULIN-LIKE GROWTH-FACTOR-I ON INTEGRINS AND OSTEOCYTE FORMATION
IMMUNOGOLD LOCALIZATION OF BETA(1)-INTEGRIN IN BONE - EFFECT OF GLUCOCORTICOIDS AND INSULIN-LIKE GROWTH-FACTOR-I ON INTEGRINS AND OSTEOCYTE FORMATION
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DOI：
10.1177/43.11.7560891
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发表时间：
1995-11-01
影响因子：
3.2
通讯作者：
GRONOWICZ, GA
中科院分区：
文献类型：
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作者：
GOHEL, AR;HAND, AR;GRONOWICZ, GA
胰岛素样生长因子I（IGP-I）和高剂量糖皮质激素对骨形成产生相反的作用。由于整联蛋白参与细胞和基质组织，因此研究了糖皮质激素和IGF-I对骨中整联蛋白的影响。应用免疫金透射电镜（TEM）技术，建立了体外矿化的胎鼠顶骨器官培养体系。在顶骨培养中，100 mM皮质酮处理72小时可使钙化减少29%，破坏成骨细胞的组织结构，并减少骨细胞的数量。成骨细胞突起的数量和每单位骨面积的骨细胞数量分别减少48%和56%，这种作用呈剂量依赖性。免疫金透射电镜显示，β（1）-整联蛋白亚基同样位于成骨细胞的顶端和基底表面。与未处理的对照培养物相比，皮质酮（100 nM）使β（1）降低了三分之一。与此相反，治疗与IGF-I 72小时增加钙化38%，细胞过程71%，和骨细胞每单位面积的骨107%，金颗粒定位Pr的成骨细胞质膜上的数量增加了一倍，几乎完全在成骨细胞的顶端表面。糖皮质激素和IGF-I对骨细胞中β 1水平没有显著影响。总之，糖皮质激素和IGF-I调节成骨细胞的整合素水平，并影响骨细胞的形成和骨钙化。然而，糖皮质激素和IGP-I都不能改变骨细胞上的β（1）-整合素水平。
Insulin-like growth factor I (IGP-I) and high-dose glucocorticoids exert opposite effects on bone formation. Because integrins are involved in cell and matrix organization, the effect of glucocorticoids and IGF-I on integrins was investigated in bone. An immunogold transmission electron microscopic (TEM) method was developed and applied to an organ culture system of 20-day fetal rat parietal bones, which mineralize in vitro. In parietal bone culture, 100 mM corticosterone treatment for 72 hr decreased calcification by 29%, disrupted osteoblast organization, and decreased the number of osteocytes, The quantity of osteoblast processes and the number of osteocytes per unit bone area were decreased by 48% and 56%, respectively, This effect was dose-dependent. The beta(1)-integrin subunit was localized equally to apical and basal osteoblast surfaces by immunogold TEM. Compared to untreated control cultures, corticosterone (100 nM) decreased beta(1) by one third. In contrast, treatment with IGF-I for 72 hr increased calcification by 38%, cell processes by 71%, and osteocytes per unit area of bone by 107%, The number of gold particles localizing Pr on the osteoblast plasma membrane doubled, almost entirely on the apical surface of the osteoblast. Glucocorticoids and IGF-I had no significant effect on beta(1) levels in osteocytes. In conclusion, glucocorticoids and IGF-I modulate integrin levels on osteoblasts, and influence osteocyte formation and bone calcification. However, neither glucocorticoids nor IGP-I alter beta(1)-integrin levels on osteocytes.