Increased Cellular Presence After Sciatic Neurectomy Improves the Bone Mechano-adaptive Response in Aged Mice

We examined bone adaptation in four groups of female C57BL/6J mice, 20 –22 months old: (1) sham surgery + 9N loading; (2) sciatic neurectomy, sacrificed after 5 days; (3) sciatic neurectomy, sacrificed after 19 days; (4) sciatic neurectomy + 9N loading. We examined changes in bone cross sectional properties with micro-CT images, and static and dynamic hist omorphometry with histological sections taken at the midpoint between tibiofibular junctions. The response to loading at 9N was not detectable with quantitative micro-CT data, but surface-specific histomorphometry captured an increase in bone formation in specific regions. 5 days following sciatic neurectomy, the amount of bone in the neurectomized leg was the same as the contralateral leg, but 19 days following sciatic neurectomy, there was significant bone loss in the neurectomized leg, and both osteoclasts and osteoblasts were recruited to the endosteal surfaces. When sciatic neurectomy a nd loading at 9N were combined, 3 out of 4 bone quadrants had increased bone formation, on the endosteal and periosteal surfaces (increased osteoid surface and mineralizing surface respectively). These data demonstrate that sciatic neurectomy increases cellular presence on the endosteal surface. Wit h long-term sciatic-neurectomy, both osteoclasts and osteoblasts were recruited to the endosteal surface, which resulted in increased bone formation when combined with a sufficient mechanical stimulus. Controlled and localized...

Source: Calcified Tissue International - June 25, 2019 Category: Orthopaedics Source Type: research