PTH signaling mediates perilacunar remodeling during exercise
| Autor: | Salam Al-Omaishi, Michael D. Morris, David H. Kohn, Joseph D. Gardinier |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Male
0301 basic medicine medicine.medical_specialty Parathyroid hormone 030209 endocrinology & metabolism Endogeny Spectrum Analysis Raman Article Bone remodeling Mice 03 medical and health sciences 0302 clinical medicine Treadmill running Physical Conditioning Animal Internal medicine medicine Animals Tibia Molecular Biology Chemistry Spectrometry X-Ray Emission Biomechanical Phenomena Fibroblast Growth Factor-23 030104 developmental biology medicine.anatomical_structure Endocrinology Parathyroid Hormone Osteocyte Exercise Test Microscopy Electron Scanning Cortical bone Bone Remodeling Signal transduction Signal Transduction |
| Zdroj: | Matrix Biology. :162-175 |
| ISSN: | 0945-053X |
| DOI: | 10.1016/j.matbio.2016.02.010 |
| Popis: | Mechanical loading and release of endogenous parathyroid hormone (PTH) during exercise facilitate the adaptation of bone. However, it remains unclear how exercise and PTH influence the composition of bone and how exercise and PTH-mediated compositional changes influence the mechanical properties of bone. Thus, the primary purpose of this study was to establish compositional changes within osteocytes’ perilacunar region of cortical bone following exercise, and evaluate the influence of endogenous PTH signaling on this perilacunar adaptation. Raman spectroscopy, Scanning electron microscopy (SEM), and Energy Dispersive X-ray Spectroscopy (EDS) were used to evaluate tissue composition surrounding individual lacuna within the tibia of 19 week old male mice exposed to treadmill running for 3 weeks. As a result of exercise, tissue within the perilacunar region (within 0–5 μm of the lacuna wall) had a lower Mineral-to-Matrix Ratio (MMR) compared to sedentary controls. In addition, exercise also increased the Carbonate-to-Phosphate Ratio (CPR) across both perilacunar and non-perilacunar regions (5–10 μm and 10–15 μm from the lacuna walls). Tibial post-yield work had a significant negative correlation with perilacunar MMR. Inhibition of PTH activity with PTH(7–34) demonstrated that perilacunar remodeling during exercise was dependent on the cellular response to endogenous PTH. The osteocytes’ response to endogenous PTH during exercise was characterized by a significant reduction in SOST expression and significant increase in FGF-23 expression. The potential reduction in phosphate levels due to FGF-23 expression may explain the increase in carbonate substitution. Overall, this is the first study to demonstrate that adaptation in tissue composition is localized around individual osteocytes, may contribute to the changes in whole bone mechanics during exercise, and that PTH signaling during exercise contributes to these adaptations. |
| Databáze: | OpenAIRE |
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