Synchrotron Ultraviolet Microspectroscopy on Rat Cortical Bone: Involvement of Tyrosine and Tryptophan in the Osteocyte and Its Environment

Abstract

Alcohol induced osteoporosis is characterized by a bone mass decrease and microarchitecture alterations. Having observed an excess in osteocyte apoptosis, we aimed to assess the bone tissue biochemistry, particularly in the osteocyte and its environment. For this purpose, we used a model of alcohol induced osteoporosis in rats. Bone sections of cortical bone were investigated using synchrotron UV-microspectrofluorescence at subcellular resolution. We show that bone present three fluorescence peaks at 305, 333 and 385 nm, respectively corresponding to tyrosine, tryptophan and collagen. We have determined that tyrosine/collagen and tryptophan/collagen ratios were higher in the strong alcohol consumption group. Tryptophan is related to the serotonin metabolism involved in bone formation, while tyrosine is involved in the activity of tyrosine kinases and phosphatases in osteocytes. Our experiment represents the first combined synchrotron UV microspectroscopy analysis of bone tissue with a quantitative biochemical characterization in the osteocyte and surrounding matrix performed separately.

Deep UV excited muscle cell autofluorescence varies with the fibre type

“…17,25,37,38 In the literature, fluorescence emission around 410 nm is usually assigned to collagen or elastin, 25 but these proteins are specific to the extracellular space, and are completely absent in the intracellular space where the measurements were made. Irrespective of the fibre type and cell localization, all spectra show the same shape (see The spectrum shows two peaks at 332 and 410 nm with a shoulder at 302 nm.…”

Protein Matrix Involved in the Lipid Retention of Foie Gras during Cooking: A Multimodal Hyperspectral Imaging Study

“…The high brightness and high spatial resolution provided by the DISCO synchrotron beamline allowed the protein matrix to be characterized on an ultrastructural scale on raw and cooked foie gras. The UV spectra of duck foie gras ( Figure 3) showed a marked peak at 333 nm assigned to the autofluorescence of tryptophan, 10,19 with a shoulder at 305 nm characteristic of tyrosine. 19 The band at 405 nm that could be assigned to collagen was not as welldefined as in human pathologic fibrosis studies.…”

“…The UV spectra of duck foie gras ( Figure 3) showed a marked peak at 333 nm assigned to the autofluorescence of tryptophan, 10,19 with a shoulder at 305 nm characteristic of tyrosine. 19 The band at 405 nm that could be assigned to collagen was not as welldefined as in human pathologic fibrosis studies. 10 This result is not surprising since foie gras is not the result of a disease, unlike human steatosis, which causes liver fibrosis.…”

Assessment of adeno-associated virus gene therapies efficacy on acid alpha-glucosidase restoration and glycogen storage correction in cardiac muscle of Pompe disease mice using synchrotron infrared and ultraviolet microspectroscopies

“…[33][34][35] Nicotinamide adenine dinucleotide (NADH), collagen cross-links, tyrosine, elastin and tryptophan can be localised without any external probe or staining at high spatial resolution. [35][36][37][38][39][40] In this study, we highlight the potential of sFT-IR microspectroscopy to investigate the cardiac muscle during the course of Pompe disease as well as to assess the efficacy of hGAA-AAV vectors in GAA-KO 6 neo /6 neo mice. Multivariate statistics applied to IR spectra between 4000 cm -1 and 950 cm -1 highlighted the potential of sFT-IR to discriminate Pompe, Wild type (Wt) and AAV-treated animals from C-H stretching vibrations of CH 3 and CH 2 (3000-2800 cm -1 ), from C-O, C-N and C-C stretching vibrations of amide I, II, III bands (1700-1300 cm -1 ) and from specific IR signatures of glycogen (1152 cm -1 , 1080 cm -1 , 1025 cm -1 ).…”