MECHANICAL LOADING AND BONE

机械负载和骨骼

• 批准号: 7742667
• 负责人: Hiroki Yokota
• 金额: $ 21.98万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-30 至 2010-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7742667
• 关键词: Adverse effects; Animals; Architecture; Biological Assay; Biological Models; Biomedical Engineering; Bone remodeling; C57BL/6 Mouse; Chondrocytes; Collagen; Data; Diaphyses; Distant; Elbow; Electronics; Environment; Fluorescein; Fluoresceins; Fluorescence Recovery After Photobleaching; Fluorescent Dyes; Frequencies; Gene Expression; Genes; Goals; Immunoblotting; In Situ; In Vitro; Inflammation; Intercellular Fluid; Interferometry; Joints; Knowledge; Lactalbumin; Lateral; Location; Matrix Metalloproteinases; Measures; Mechanical Stimulation; Mechanics; Messenger RNA; Microscopic; Minerals; Monitor; Mus; Osteoblasts; Osteogenesis; Pattern; Research; Research Personnel; Resolution; Role; Sodium Fluorescein; Stress; Surface; Synovial Membrane; Testing; Therapeutic; Time; Transport Process; articular cartilage; base; bone; bone cell; bone epiphysis; bone loss; bone mass; enzyme activity; fluid flow; in vivo; joint loading; long bone; novel; prevent; programs; protein expression; prototype; response; skeletal; ulna

The long-term objective of the proposed studies is to elucidate the mechanism of mechanotransduction in bone. Our present bioengineering-oriented project developed a high-resolution piezoelectric mechanical loader and evaluated the role of mechanical stimulation in bone using cultured osteoblasts. The results reveal that (a) deformation of 3D collagen matrix can induce strain-induced fluid flow; (b) strain-induced fluid flow, and not strain itself, predominantly activates the stress-responsive genes in osteoblasts; and (c) architecture of 3D collagen matrix establishes a pattern of strain-induced fluid flow and molecular transport. Many lines of evidence in animal studies support enhancement of bone remodeling with strain of 1000 - 2000 microstrains. An unclear linkage between our in vitro studies and these animal studies is the role of strain and fluid flow in bone remodeling. In vitro osteoblast cultures including our current studies use 2D substrates or 3D matrices that hardly mimic the strain-induced fluid flow in vivo. This difference between in vitro and in vivo data makes it difficult to evaluate the role of strain and fluid flow in bone remodeling and anti-inflammation. First, microscopic strain in bone might be higher than the macroscopic strain measured with strain gauges. A local microscopic strain higher than 1000 - 2000 microstrains may therefore drive fluid flow in bone. Second, the lacunocanalicular network in bone could amplify strain-induced fluid flow in a loading-frequency dependent fashion. Lastly, interstitial fluid flow in bone might be induced by in situ strain as well as strain in a distant location, such that deformation of relatively soft epiphyses induces fluid flow in cortical bone in diaphyses. This renewal proposal will use mouse ulnae ex vivo as well as mouse in vivo loading to examine the above possible explanations for the data divergence. Specific aims include: (1) fabricating a piezoelectric mechanical loader for ex vivo and in vivo use; (2) quantifying ex vivo macroscopic and microscopic strains using electronic speckle pattern interferometry as well as molecular transport using fluorescence recovery after photobleaching; (3) conducting bone histomorphometry to evaluate ex vivo data; and (4) examining load-driven adverse effects with gene expression and enzyme activities (e.g., matrix metalloproteinases). Mechanical loads will be given in the ulna-loading (axial loading) and elbow-loading (lateral loading) modes. These two modes have been shown to enhance bone remodeling in the diaphysis with different patterns of strain distribution. Successful completion of the proposed renewal proposal will provide basic knowledge about induction of fluid flow in bone and establish a research platform for devising therapeutic strategies for strengthening bone and preventing bone loss.

拟议研究的长期目标是阐明机械传导的机制 骨。我们目前的生物工程导向项目开发了一种高分辨率压电机械 装载机并使用培养的成骨细胞评估了机械刺激在骨骼中的作用。结果 揭示 (a) 3D 胶原基质的变形可以诱导应变诱导的流体流动； (b) 应变引起的流体 流动而非应变本身主要激活成骨细胞中的应激反应基因；和（三） 3D 胶原蛋白基质的结构建立了应变诱导的流体流动和分子运输的模式。 动物研究中的许多证据支持 1000 应变可增强骨重塑 - 2000 微应变。我们的体外研究和这些动物研究之间尚不清楚的联系是 骨重塑中的应变和流体流动。体外成骨细胞培养（包括我们当前的研究）使用 2D 基质或 3D 矩阵很难模拟体内应变诱导的流体流动。这种差异在 体外和体内数据使得评估应变和流体流动在骨重塑和骨重建中的作用变得困难。 抗炎。首先，骨骼中的微观应变可能高于测量到的宏观应变 与应变计。因此，高于 1000 - 2000 微应变的局部微观应变可能会驱动流体 流于骨中。其次，骨骼中的腔隙小管网络可以放大应变诱导的流体流动 加载频率相关的时尚。最后，骨中的间质液流动可能是由原位应变引起的 以及远处位置的应变，使得相对较软的骨骺的变形引起流体流动 骨干中的皮质骨。 该更新提案将使用小鼠尺骨离体以及小鼠体内负载来检查上述内容 数据差异的可能解释。具体目标包括：（1）制造压电 用于离体和体内使用的机械装载机； (2) 量化离体宏观和微观菌株 使用电子散斑干涉测量以及使用荧光恢复的分子传输 光漂白后； (3)进行骨组织形态计量学以评估离体数据； (4) 检查 负载驱动的基因表达和酶活性（例如基质金属蛋白酶）的不利影响。 机械载荷将以尺骨载荷（轴向载荷）和肘部载荷（横向载荷）模式给出。 这两种模式已被证明可以通过不同的模式增强骨干的骨重塑。 应变分布。成功完成所提出的续约提案将提供基础知识 关于诱导骨中液体流动并建立一个研究平台来设计治疗策略 强化骨骼并防止骨质流失。