Oxysterols enhance osteoblast differentiation in vitro and bone healing in vivo
Oxysterols enhance osteoblast differentiation in vitro and bone healing in vivo
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DOI：
10.1002/jor.20437
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发表时间：
2007-11-01
影响因子：
2.8
通讯作者：
Tetradis, Sotirios
中科院分区：
文献类型：
--
作者：
Aghaloo, Tara L.;Amantea, Christopher M.;Tetradis, Sotirios
氧化甾醇是天然产生的胆固醇氧化产物，可诱导成骨细胞分化。我们研究了22(S)-羟胆固醇+ 20(S)-羟胆固醇（SS）短期暴露对骨髓基质细胞成骨分化的影响。我们进一步探索了氧甾醇在体内促进骨愈合的能力。通过碱性磷酸酶（ALP）活性、骨钙素（OCN） mRNA表达、矿化和Runx2 DNA结合活性来评估成骨分化。为了探讨成骨氧甾醇在体内的作用，我们采用了临界尺寸的大鼠颅骨缺损模型。将聚乳酸-羟基乙酸（PLGA）支架单独或包被140 ng（低剂量）或1400 ng（高剂量）的氧甾醇混合物植入缺损。6周处死大鼠，三维（3D）微计算机断层扫描（MicroCT）检查。测定骨体积（BV）、总积（TV）及BV/TV比值。SS培养10 min可显著提高4 d后ALP活性，2 h可显著提高14 d后ALP矿化程度。4小时的SS处理增加了8天后测量的OCN mRNA和4天后测量的核蛋白与OSE2位点的结合。对照组颅骨缺损骨愈合轻微。然而，低剂量或高剂量的混合氧甾醇吸附支架可显著促进骨形成。组织学检查证实，与对照部位的大部分纤维组织相比，移植了氧甾醇吸附支架的缺损部位形成了骨。我们的研究结果表明，短暂暴露于成骨氧甾醇会引发体外成骨细胞分化和功能以及体内骨形成的事件。这些结果确定了氧甾醇是局部和全身增强骨形成的潜在药物。(C) 2007骨科研究学会。Wiley期刊公司出版。
Oxysterols, naturally occurring cholesterol oxidation products, can induce osteoblast differentiation. Here, we investigated short-term 22(S)-hydroxycholesterol + 20(S)-hydroxycholesterol (SS) exposure on osteoblastic differentiation of marrow stromal cells. We further explored oxysterol ability to promote bone healing in vivo. Osteogenic differentiation was assessed by alkaline phosphatase (ALP) activity, osteocalcin (OCN) mRNA expression, mineralization, and Runx2 DNA binding activity. To explore the effects of osteogenic oxysterols in vivo, we utilized the critical-sized rat calvarial defect model. Poly(lactic-co-glycolic acid) (PLGA) scaffolds alone or coated with 140 ng (low dose) or 1400 ng (high dose) oxysterol cocktail were implanted into the defects. Rats were sacrificed at 6 weeks and examined by three-dimensional (3D) microcomputed tomography (MicroCT). Bone volume (BV), total volume (TV), and BV/TV ratio were measured. Culture exposure to SS for 10 min significantly increased ALP activity after 4 days, while 2 h exposure significantly increased mineralization after 14 days. Four-hour SS treatment increased OCN mRNA measured after 8 days and nuclear protein binding to an OSE2 site measured after 4 days. The calvarial defects showed slight bone healing in the control group. However, scaffolds adsorbed with low or high-dose oxysterol cocktail significantly enhanced bone formation. Histologic examination confirmed bone formation in the defect sites grafted with oxysterol-adsorbed scaffolds, compared to mostly fibrous tissue in control sites. Our results suggest that brief exposure to osteogenic oxysterols triggered events leading to osteoblastic cell differentiation and function in vitro and bone formation in vivo. These results identify oxysterols as potential agents in local and systemic enhancement of bone formation. (C) 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.