title: Osteocyte lacunar properties in rat cortical bone: Differences between lamellar and central bone.
abstract: Recently, the roles of osteocytes in bone maintenance have gained increasing attention. Osteocytes reside in lacunae that are interconnected by canaliculi resulting in a vast cellular network within the mineralized bone matrix. As the structure of the lacuno-canalicular network is highly connected to osteocyte function, osteocyte lacunar properties such as volume, shape, orientation, and density are now frequently reported in studies investigating osteocyte activity. Despite this increasing interest in lacunar morphometrics, many studies show a large spread in such values, suggesting a large inter-species but also inter-site variation in lacunar properties. Here, osteocyte lacunae in rat cortical bone have been studied using synchrotron radiation micro computed tomography (SR μCT) and backscattered electron (BE) microscopy. Quantitative lacunar geometric characteristics are reported based on the synchrotron radiation data, differentiating between circumferential lamellar bone and a central, more disordered bone type. From these studies, no significant differences were found in lacunar volumes between lamellar and central bone, whereas significant differences in lacunar orientation, shape and density values were observed. The 3D nature of the SR μCT data sets furthermore revealed that lacunae in central bone, which appear to be poorly aligned in transverse 2D cross sections, are in fact highly aligned along the bone long axis. These results demonstrate the importance of using 3D methods to investigate anisotropic biological materials such as bone and that the appropriate choice of subregions for high resolution imaging is not trivial.
authors.affiliation: iNANO and Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark.
authors.forename: Fiona Linnea
authors.initials: FL
authors.lastname: Bach-Gansmo
authors.affiliation: Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, United States.
authors.forename: James C
authors.initials: JC
authors.lastname: Weaver
authors.affiliation: iNANO and Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark.
authors.forename: Mads Hartmann
authors.initials: MH
authors.lastname: Jensen
authors.affiliation: iNANO and Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark.
authors.forename: Hanna
authors.initials: H
authors.lastname: Leemreize
authors.affiliation: Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland; Institute for Biomedical Engineering, Swiss Federal Institute of Technology and University of Zurich, Zurich, Switzerland.
authors.forename: Kevin Scott
authors.initials: KS
authors.lastname: Mader
authors.affiliation: Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland; Institute for Biomedical Engineering, Swiss Federal Institute of Technology and University of Zurich, Zurich, Switzerland.
authors.forename: Marco
authors.initials: M
authors.lastname: Stampanoni
authors.affiliation: Department of Biomedicine, Aarhus University, Aarhus, Denmark.
authors.forename: Annemarie
authors.initials: A
authors.lastname: Brüel
authors.affiliation: Department of Biomedicine, Aarhus University, Aarhus, Denmark.
authors.forename: Jesper Skovhus
authors.initials: JS
authors.lastname: Thomsen
authors.affiliation: iNANO and Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark. Electronic address: hbirkedal@chem.au.dk.
authors.forename: Henrik
authors.initials: H
authors.lastname: Birkedal
mesh_terms: D000818:Animals; D005260:Female; D010011:Osteocytes / Q000000981:diagnostic imaging*; D051381:Rats; D017208:Rats, Wistar; D055114:X-Ray Microtomography
keywords: Backscattered electron imaging; Endochondral bone; Lamellar bone; Microcomputed tomography; Osteocyte lacunae; Osteocytes