A Novel Experimental Technique for Quantifying the Local Mechanical Environment of Skeletal Tissues

A growing body of evidence indicates that mechanical cues modulate the development and repair of skeletal tissues by regulating gene expression and tissue differentiation.[1–3] Further understanding of how the mechanical environment modulates these biological processes could be applied to enhance skeletal repair following injury or disease. Bone healing provides an excellent in vivo system for investigating cellular responses to mechanical stimuli, due to the recruitment of pluripotent, mechano-sensitive, mesenchymal stem cells. For example, recent studies have shown that bending and/or shear motion applied to a healing bone defect can result in cartilage rather than bone formation.[4,5] However, while different global (i.e. organ level) mechanical stimuli are known to result in different healing outcomes, the specific local (i.e. tissue level) stimuli that promote different tissue fates have yet to be established. Finite element analyses can provide estimates of these local stimuli, yet these analyses require many assumptions regarding tissue material properties and boundary conditions. Our overall goal in this study was to develop an experimental technique for quantifying the distributions of local strains that develop in skeletal tissues during mechanical loading.