Practical Considerations for the Design, Execution, and Interpretation of Studies Involving Whole-Bone Bending Tests of Rodent Bones

Resumo

Mechanical testing of rodent bones is a valuable method for extracting information regarding a bone's susceptibility to fracture. Lacking proper practical understanding, the results may be overinterpreted or lack validity. This protocol will serve as a guide to ensure mechanical tests are performed accurately to provide valid and functional data.

Resumo

Skeletal fragility leading to fracture is an American public health crisis resulting in 1.5 million fractures each year and $18 billion in direct care costs. The ability to understand the mechanisms underlying bone disease and the response to treatment is not only desired, but critical. Mechanical testing of bone serves as a valuable technique for understanding and quantifying a bone's susceptibility to fracture. While this method appears simple to perform, inappropriate and inaccurate conclusions may be reached if governing assumptions and key steps are disregarded by the user. This has been observed across disciplines as studies continue to be published with misuse of methods and incorrect interpretation of results. This protocol will serve as a primer for the principles associated with mechanical testing along with the application of these techniques-from considerations of sample size through tissue harvesting and storage, to data analysis and interpretation. With this in hand, valuable information regarding a bone's susceptibility to fracture may be obtained, furthering understanding for both academic research and clinical solutions.

Introdução

Mechanical testing of bone is the primary method to extract functional information related to a bone's susceptibility to fracture. In preclinical studies, several testing modalities can be used but by far the most common is the bending of long bones. These tests are easy to perform and can be used on bones ranging in size from human to mouse. As mice are one of the most commonly studied animals in preclinical research, this protocol will focus on bending tests performed on the femora and tibiae of mice.

Prior to performing bending tests, bones must be properly harvested and stored. The most common storage methods have traditionally been....

Protocolo

All procedures described throughout this protocol that involved animals have been approved by the Indiana University School of Science Institutional Animal and Use Committee (IACUC) prior to the procedure. Animals described in the procedure were euthanized via CO₂inhalation followed by cervical dislocation as a secondary means of euthanasia.

1. Harvest, storage, and thawing of bones

1. Harvest and storage
   1. Place the mouse ventral side up. Use a scalpel (or a razor blade or scissors) to make an incision at the approximate junction of the femur and pelvis on one side.
   2. Continue the ini....

Discussão

Throughout the scanning and testing process, there are moments when troubleshooting and optimization are appropriate. The first of these occurs when scanning bones using µCT. While many systems come with a holder in which one object may be held and scanned, custom holders can be fabricated to scan multiple bones at the same time. Scanning multiple bones can be an excellent point for optimization, but caution should be taken throughout the scanning and analysis process to ensure artifacts are not being induced. As X-.......

Materiais

Name	Company	Catalog Number	Comments
CTAn	Bruker	NA	CT Scan Analysis Software
DataViewer	Bruker	NA	CT Scan Rotation Software
Matrix Laboratory (MATLAB) 2023a	MathWorks	NA	Coding platform used for data analysis
NRecon	Bruker	NA	CT Scan Reconstruction software
SKYSCAN 1272-100 kV w/ 16 MP CCD detector, incl 3D Suite Software	Micro Photonics Inc	SKY-016814	Micro-CT system that can non-destructively visualize up to 209 mPs in every virtual slice through an object