Spatiotemporal characterization of microdamage accumulation in rat ulnae in response to uniaxial compressive fatigue loading.

摘要: Abstract Repetitive fatigue loading can induce microdamage accumulation in bone matrix, which results impaired mechanical properties and increased fracture susceptibility. However, the spatial distribution time-variant process of fatigue-loaded skeleton, especially for linear microcracks are known to initiate remodeling, remain not fully understood. In this study, time-varying morphology rat ulnae subjected uniaxial compressive was investigated. Right forelimbs thirty four-month-old male Sprague-Dawley rats were one bout cyclic ramp with 0.67 Hz at a normalized peak force 0.055 N/g body weight 6000 cycles, contralateral left loaded as control samples. Ten randomly euthanized on Days 3, 5, 7 post loading. Our findings via two-dimensional histomorphometric measurements based basic fuchsin staining three-dimensional quantifications using contrast-enhanced micro-computed tomography (MicroCT) precipitated BaSO4 demonstrated that (increase amount microcracks) Day 5 significantly higher than 3 histological revealed microcrack density (Cr.Dn) tensile cortex side, whereas length (Cr.Le) lower cortex. exhibited non-linear 7 days axial (with observable Cr.Dn 5). also distinct strains, characterized by more accumulated cortices, longer cracks shown cortices.