title: Micro-computed tomography assisted distal femur metaphyseal blunt punch compression for determining trabecular bone strength in mice.
abstract: Shorter generation time and the power of genetic manipulation make mice an ideal model system to study bone biology as well as bone diseases. However their small size presents a challenge to perform strength measurements, particularly of the weight-bearing cancellous bone in the murine long bones. We recently developed an improved method to measure the axial compressive strength of the cancellous bone in the distal femur metaphysis in mice. Transverse micro-computed tomography image slices that are 7µm thick were used to locate the position where the epiphysis-metaphysis transition occurs. This enabled the removal of the distal femur epiphysis at the exact transition point exposing the full extent of metaphyseal trabecular bone, allowing more accurate and consistent measurement of its strength. When applied to a murine model system consisting of five month old male wild-type (WT) and Ca(2+)/calmodulin dependent protein kinase kinase 2 (CaMKK2) knockout (KO) Camkk2(-/-) mice that possess recorded differences in trabecular bone volume, data collected using this method showed good correlation between bone volume fraction and strength of trabecular bone. In combination with micro-computed tomography and histology, this method will provide a comprehensive and consistent assessment of the microarchitecture and tissue strength of the cancellous bone in murine mouse models.
authors.affiliation: Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY, USA; James Graham Brown Cancer Center and Owensboro Cancer Research Program, University of Louisville School of Medicine, Louisville, KY, USA. Electronic address: usankar@iupui.edu.
authors.forename: Uma
authors.initials: U
authors.lastname: Sankar
authors.affiliation: Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY, USA.
authors.forename: Zachary J
authors.initials: ZJ
authors.lastname: Pritchard
authors.affiliation: Department of Orthopaedic Surgery, University of Louisville School of Medicine, Louisville, KY, USA; Department of Bioengineering, University of Louisville Speed School of Engineering, Louisville, KY, USA. Electronic address: michael.voor@louisville.edu.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Voor
mesh_terms: D000818:Animals; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase / Q000235:genetics; D019245:Compressive Strength / Q000502:physiology; D005269:Femur / Q000000981:diagnostic imaging* / Q000502:physiology*; D008297:Male; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D016474:Weight-Bearing / Q000502:physiology; D055114:X-Ray Microtomography
chemical_list: D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase; C517700:Camkk2 protein, mouse
keywords: Blunt punch compression; Distal femur; Metaphyseal cancellous bone strength; Micro-CT; Mouse models