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.

拟议的研究的长期目标是阐明机械转导机理 骨。我们目前以生物工程为导向的项目开发了高分辨率压电机械 加载器并使用培养的成骨细胞评估了机械刺激在骨中的作用。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）应变诱导的液体 流动而不是劳累，主要会激活成骨细胞中的应激响应基因。 （c） 3D胶原基质的结构建立了应变诱导的流体流量和分子转运的模式。 动物研究中的许多证据都支持增强骨重塑，菌株为1000- 2000微构元。我们的体外研究与这些动物研究之间的不清楚联系是 骨重塑中的应变和流体流动。包括我们当前研究在内的体外成骨细胞培养物使用2D 几乎无法模仿体内应变诱导的流体流量的底物或3D矩阵。在 体外和体内数据使得很难评估菌株和液体流动在骨骼重塑和 抗炎。首先，骨骼中的微观菌株可能高于测得的宏观菌株 与应变仪。因此，高于1000-2000微晶体的局部微观菌株可能会驱动流体 骨头流动。其次，骨骼中的lacunocanalicular网络可以放大A中应变诱导的流体流动 加载频率依赖于时尚。最后，骨骼中的间质流体可能由原位应变诱导 以及在遥远位置的应变，使得相对较软的表周的变形诱导流体流动 膜片中的皮质骨。 该更新建议将使用鼠标脱骨外体和体内载荷的鼠标来检查上述 数据差异的可能解释。具体目的包括：（1）制造压电 用于体内和体内使用的机械装载机； （2）定量体内宏观和微观菌株 使用电子斑点模式干涉法以及使用荧光回收的分子转运 光漂白后； （3）进行骨骼组态法以评估离体数据； （4）检查 负载驱动的不良反应具有基因表达和酶活性（例如基质金属蛋白酶）。 机械载荷将在尺骨加载（轴向载荷）和肘部加载（横向加载）模式中给出。 这两种模式已被证明可以增强肌椎骨的骨头重塑，并以不同的模式 应变分布。成功完成拟议的续签建议将提供基本知识 关于骨骼中的液体流动的诱导，并建立了一个研究平台，以设计治疗策略 增强骨骼并防止骨质流失。