Development of photometric detection system for tissue aging and study the localization of the aging in tissue

本项目的目的是开发一种能够检测活体组织老化的有效测光系统，并研究组织老化的定位。本课题的研究成果如下：(1)研制了亚纳秒分辨率的时间分辨共焦显微镜系统。该系统可用于三维动态荧光图像的测量。在荧光寿命图像测量的基础上，展示了酵母细胞内钙离子浓度的图像。(2)用醋酸从人牙本质中提取了荧光胶原蛋白。牙齿提取胶原蛋白的荧光光谱与牙本质组织的荧光光谱一致。牙齿提取胶原蛋白的荧光强度随着年龄的增长和在核糖溶液中反应时间的延长而增强。我们的结论是，年龄相关荧光发射的主要荧光团是组织胶原蛋白与还原糖反应产生的高级糖基化终产物。(3)构建了二次谐波产生光(SHG-LIGH)检测系统。SHG-LIGHT对组织胶原构象敏感。用Ar-微波等离子体发射光谱仪测量了人肱动脉分叉处的钙含量，并考虑了钙含量与动脉壁力学性能之间的可能关系。我们发现钙沉积显著的部位是壁面切应力较低的区域，并认为动脉硬化发生在壁面切应力较低的区域。

The aim of this project is to develop an effective photometry system that can detect tissue aging of living body and to study the localization of tissue aging. The results of the project are described in the following.(1) A time-resolved confocal-microscope system with subnanosecond-resolution has been developed. Three-dimensional kinetic fluorescence image can be measured with this system. Image of calcium concentration in an yeast cell has been demonstraed based on the fluorescence lifetime image measurement.(2) Fluorescent collagen has been extracted from human dentin using acetic acid. The fluorescence spectra of the tooth-extracted collagen was consistent with that of the dentin tissue. Also the fluorescence intensity of the tooth-extracted collagen increased with the age, and with reaction time in the ribose solution. We have concluded that the main fluorophore of the age dependent fluorescence emission is AGE (Advanced Glycosylation Endproduct) that is generated in tissue collagen by the reaction with reducing sugar.(3) The second-harmonic generation light (SHG-light) detection system has been constructed. SHG-light is sensitive to tissue collagen conformation. We found that orientation of the collagen fiber has been informed by the SHG light.(4) Calcium content at bifurcation of the human brachial artery has been measured with an Ar-microwave-induced plasma emission spectrophotometer, and a possible correlation between Ca content and mechanical property of the artery wall has been considered. We have found that the portions in which Ca deposition is significant are the regions of low wall shear stress, and concluded that arteriosclerosis occurs in the regions of low wall share stress.