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

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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.