Synchrotron ultraviolet microspectroscopy on rat cortical bone: involvement of tyrosine and tryptophan in the osteocyte and its environment

PLoS One. 2012;7(8):e43930. doi: 10.1371/journal.pone.0043930. Epub 2012 Aug 28.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bone Density / physiology
  • Bone and Bones / metabolism*
  • Ethanol
  • Male
  • Microspectrophotometry
  • Osteocytes / metabolism*
  • Osteogenesis / physiology*
  • Osteoporosis / chemically induced
  • Osteoporosis / metabolism*
  • Rats
  • Rats, Wistar
  • Tryptophan / metabolism*
  • Tyrosine / metabolism*

Substances

  • Ethanol
  • Tyrosine
  • Tryptophan

Grants and funding

This work was supported by beam time allocations at SOLEIL Synchrotron (proposal 20090113) and by the FEDER and Région Centre grant «IBIFOS». The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.