Dynamic Spectroscopic Imaging in Bone Biomechanics

描述（由申请人提供）： 总体项目目标是开发拉曼成像，并将其应用于拉伸和压缩载荷下组织中骨矿物质微晶晶格和基质胶原二级结构的变化。线聚焦532 nm激光将用于激发荧光团化学和光化学漂白预处理组织的光谱。成像摄谱仪和微光CCD将提供空间分辨光谱，并能够测量0.1-0.2 cm（-1）的位置变化峰值，积分时间低至0.05秒。该项目是在原子和分子结构一级研究骨质疏松组织失效机制的第一阶段，目的是制定新的干预战略，尽量减少骨折风险。该项目还将作为研究生物力学和其他代谢疾病以及肌肉骨骼组织遗传缺陷的模型。将使用牛骨开发技术，然后移植到存档的人体组织标本中。我们的假设是：在弹性变形过程中，骨矿物质中的离子间距在机械应力下发生变化，而塑性变形（开裂、压缩或断裂）导致永久性变化。2）基质通过交联的扰动和胶原原纤维链螺旋间距的变化对弹性状态下的机械应力做出响应，导致螺旋和卷曲构象以及氢键的变化。在塑性变形中，胶原纤维之间的交联断裂。这些假设可以通过组织的光谱成像来检验，因为振动频率和强度响应于局部环境的变化。静态拉曼成像将探索已经经受疲劳载荷的组织的化学。动态成像将跟踪骨组织化学参数随施加载荷的变化。将使用单变量和多变量方法进行数据简化。将对小鼠组织进行年龄效应的系统研究，并对极端年龄的人体组织进行探索性研究。

DESCRIPTION (provided by applicant): The overall project goals are development of Raman imaging with application to changes in bone mineral crystallite lattice and matrix collagen secondary structure in tissue subjected to tensile and compressive loading. Line-focused 532 nm laser light will be used to excite spectra of tissue pretreated by chemical and photochemical bleaching of fluorophores. An imaging spectrograph and low-light level CCD will provide spatially resolved spectra and ability to measure 0.1-0.2 cm(-1) changes peak in position with integration times as low as 0.05 sec. The project is the first phase of a study of the failure mechanism of osteoporotic tissue at the level of atomic and molecular structure, with the goal of new intervention strategies for minimization of fracture risk. The project will also serve as a model for study of biomechanics and other metabolic diseases and genetic defects of musculoskeletal tissue. Techniques will be developed using bovine bone and then ported to archived human tissue specimens. Our hypotheses are: Ion spacing in bone mineral change under mechanical stress during elastic deformation, while plastic deformation (cracking, compression or fracture) results in permanent changes 2) The matrix responds to mechanical stress in the elastic regime by perturbation of cross-links and changes in helix pitch of the strands of the collagen fibrils, resulting in changes in helix and coil conformations and hydrogen bonding. In plastic deformation cross-links between collagen fibrils are ruptured. These hypotheses can be tested by spectroscopic imaging of tissue because vibratioal frequencies and intensities respond to changes in local environment. Static Raman imaging will explore chemistry of tissue that has been subjected to fatigue loading. Dynamic imaging will follow changes in bone tissue chemical parameters with applied loads. Both univariate and multivariate methods will be used for data reduction. Systematic studies of age effects will be performed on murine tissue with exploratory work on human tissue at age extremes.