Dynamic Spectroscopic Imaging in Bone Biomechanics

描述(由申请人提供)： 该项目的总体目标是发展拉曼成像，应用于组织在拉伸和压缩载荷下的骨矿物质、微晶晶格和基质胶原二级结构的变化。线聚焦532 nm激光将被用来激发经荧光团的化学和光化学漂白处理的组织的光谱。成像光谱仪和微光CCD将提供空间分辨率的光谱和测量0.1-0.2厘米(-1)峰位置变化的能力，积分时间低至0.05秒。该项目是在原子和分子结构水平上研究骨质疏松组织失效机制的第一阶段，目的是寻找新的干预策略，将骨折风险降至最低。该项目还将作为研究肌肉骨骼组织的生物力学和其他代谢性疾病和遗传缺陷的模型。将利用牛骨开发技术，然后移植到存档的人类组织标本中。我们的假设是：在弹性变形过程中，骨矿物中的离子间距在机械应力的作用下发生变化，而塑性变形(破裂、压缩或断裂)会导致永久性的变化。2)在弹性状态下，基质通过交联键的扰动和胶原原纤维螺旋间距的变化来响应机械应力，导致螺旋和螺旋构象的变化以及氢键的变化。在塑性变形中，胶原纤维之间的交联会断裂。这些假说可以通过组织的光谱成像来检验，因为振动的频率和强度会对局部环境的变化做出反应。静态拉曼成像将探索承受疲劳载荷的组织的化学成分。动态成像将跟踪骨组织化学参数随施加载荷的变化。数据约简将采用单变量和多变量两种方法。对年龄效应的系统研究将在小鼠组织上进行，在年龄极端的人类组织上进行探索性工作。

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.