Laurent Maïmoun1, Tara C Brennan-Speranza, René Rizzoli, Patrick Ammann. 1. Division of Bone Diseases, Department of Rehabilitation and Geriatrics, Geneva University Hospitals and Faculty of Medicine, 4 Rue Gabrielle Perret-Gentil, 1211 Geneva 14, Switzerland.
Abstract
BACKGROUND: Ovariectomy (OVX) and immobilization are known to decrease bone mineral density and alter its microarchitecture. Their effects on the material level properties of bone, a determinant of bone strength, are still largely unknown. We investigated the effect of OVX and/or disuse achieved by sciatic neurectomy (NX) in 6-month-old Sprague Dawley female rats. METHODS: At baseline, animals underwent OVX or sham operation. At week 16, NX was performed on the left hindlimb while the right hindlimb was sham-operated. All animals were sacrificed at week 40. Proximal tibiae and vertebral bodies (L4) were evaluated by micro-computed tomographic morphometry (μCT). Material level properties (elastic modulus, hardness, and dissipated energy) were evaluated by a nanoindentation test. RESULTS: At the proximal tibia, OVX and NX decreased relative bone volume, the former mainly through a reduction in trabecular number, and the latter through a decrease in trabecular thickness. NX decreased modulus (-10%; p<0.001) and dissipated energy (-13.3%, p<0.001) in cortical bone, and modulus (-16.8%, p=0.004), hardness (-29.3%, p=0.004), and dissipated energy (-17.7%, p=0.01) in trabecular bone, while OVX decreased cortical bone dissipated energy (-14.6%, p<0.001) and trabecular bone hardness (-19.4%, p=0.05). In the vertebral body, OVX altered mainly the trabecular microarchitecture and nanoindentation variables. CONCLUSION: These results show that NX with and without OVX markedly alter material level properties in addition to an alteration of bone microarchitecture, although not in the same manner.
BACKGROUND: Ovariectomy (OVX) and immobilization are known to decrease bone mineral density and alter its microarchitecture. Their effects on the material level properties of bone, a determinant of bone strength, are still largely unknown. We investigated the effect of OVX and/or disuse achieved by sciatic neurectomy (NX) in 6-month-old Sprague Dawley female rats. METHODS: At baseline, animals underwent OVX or sham operation. At week 16, NX was performed on the left hindlimb while the right hindlimb was sham-operated. All animals were sacrificed at week 40. Proximal tibiae and vertebral bodies (L4) were evaluated by micro-computed tomographic morphometry (μCT). Material level properties (elastic modulus, hardness, and dissipated energy) were evaluated by a nanoindentation test. RESULTS: At the proximal tibia, OVX and NX decreased relative bone volume, the former mainly through a reduction in trabecular number, and the latter through a decrease in trabecular thickness. NX decreased modulus (-10%; p<0.001) and dissipated energy (-13.3%, p<0.001) in cortical bone, and modulus (-16.8%, p=0.004), hardness (-29.3%, p=0.004), and dissipated energy (-17.7%, p=0.01) in trabecular bone, while OVX decreased cortical bone dissipated energy (-14.6%, p<0.001) and trabecular bone hardness (-19.4%, p=0.05). In the vertebral body, OVX altered mainly the trabecular microarchitecture and nanoindentation variables. CONCLUSION: These results show that NX with and without OVX markedly alter material level properties in addition to an alteration of bone microarchitecture, although not in the same manner.
Authors: Hélder Fonseca; Daniel Moreira-Gonçalves; Francisco Amado; José L Esteves; José Alberto Duarte Journal: J Bone Miner Metab Date: 2014-10-09 Impact factor: 2.626
Authors: Divya Sharma; Adriana I Larriera; Paolo E Palacio-Mancheno; Vittorio Gatti; J Christopher Fritton; Timothy G Bromage; Luis Cardoso; Stephen B Doty; Susannah P Fritton Journal: Bone Date: 2018-01-31 Impact factor: 4.398
Authors: Grace Kim; Jacqueline H Cole; Adele L Boskey; Shefford P Baker; Marjolein C H van der Meulen Journal: Calcif Tissue Int Date: 2014-06-03 Impact factor: 4.333
Authors: Stuart J Warden; Matthew R Galley; Andrea L Hurd; Joseph M Wallace; Maxime A Gallant; Jeffrey S Richard; Lydia A George Journal: Endocrinology Date: 2013-06-19 Impact factor: 4.736