Evaluating the theory of bone mechanoregulation in the physiological loading scenario

In this paper, the theory of bone mechanoregulation under physiological loading was evaluated. The entire right tibiae of wild type (WT, N=5) and parathyroid hormone (PTH, N=5) treated C57BL/6J female mice were scanned using an in vivo μCT imaging system at 14, 16, 17, 18, 19, 20, 21, and 22 weeks. The PTH intervention started from week 18 until week 22. Subject-specific finite element (FE) models were created from the μCT images and physiological loading condition was defined in the FE models. The rates of changes in bone mineral content (BMC), bone mineral density (BMD), and bone tissue density (TMD) were quantified over 40 anatomical compartments across the entire mouse tibia. The resulting values were then correlated to the average 1st principal tensile strain (ε1) and the strain energy density (SED) for every compartment at weeks 18, 20, and 22. It was found that: in both groups, ε1 had a minimal effect on the variability of ΔBMC (p>0.01); SED had a significant effect on the variability of ΔBMC only in the WT group (p<0.01); ε1 had a significant effect on the variability of ΔBMD only in the PTH group (p<0.01); SED had a significant effect on the variability of ΔBMD in both groups (p<0.01); neither SED nor ε1 had a significant effect on the variability of ΔTMD (p>0.01). These results are the first to reveal the mechanism of bone mechanoregulation in the physiological loading scenario.

Electronic version of an article published as Journal of Mechanics in Medicine and Biology, March 2018, Vol. 18, No. 02, 1850011 https://doi.org/10.1142/S0219519418500112 © copyright World Scientific Publishing Company, https://www.worldscientific.com/worldscinet/jmmb