Heffner M A, Anderson M J, Yeh G C, Genetos D C, Christiansen B A
University of California-Davis Medical Center, Department of Orthopaedic Surgery.
J Musculoskelet Neuronal Interact. 2014 Mar;14(1):1-9.
The present study sought to determine the effects of decreased peripheral sensory nerve function on skeletal development and bone metabolism in mice.
C57BL/6 neonatal mice were treated with capsaicin to induce peripheral sensory nerve degeneration, and compared to vehicle-treated controls at 4, 8 and 12 weeks of age. Changes in bone structure were assessed using micro-computed tomography, mechanical properties and fracture resistance were assessed using three-point bending of radii, and bone turnover was assessed using dynamic histomorphometry and serum biomarkers.
Capsaicin treatment resulted in small but significant decreases in bone structure, particularly affecting trabecular bone. Capsaicin-treated mice exhibited lower trabecular thickness at the femoral metaphysis and L5 vertebral body compared with vehicle-treated mice. However, capsaicin- and vehicle-treated mice had similar mechanical properties and bone turnover rates.
Neonatal capsaicin treatment affected trabecular bone during development; however these small changes may not be meaningful with respect to bone strength under normal loading conditions. It is possible that capsaicin-sensitive neurons may be more important for bone under stress conditions such as increased mechanical loading or injury. Future studies will investigate this potential role of peripheral sensory nerves in bone adaptation.
本研究旨在确定外周感觉神经功能降低对小鼠骨骼发育和骨代谢的影响。
用辣椒素处理C57BL/6新生小鼠以诱导外周感觉神经变性,并在4周、8周和12周龄时与用赋形剂处理的对照小鼠进行比较。使用微型计算机断层扫描评估骨结构变化,使用桡骨三点弯曲评估力学性能和抗骨折能力,使用动态组织形态计量学和血清生物标志物评估骨转换。
辣椒素处理导致骨结构出现虽小但显著的下降,尤其影响小梁骨。与用赋形剂处理的小鼠相比,用辣椒素处理的小鼠在股骨干骺端和L5椎体处的小梁厚度较低。然而,用辣椒素处理的小鼠和用赋形剂处理的小鼠具有相似的力学性能和骨转换率。
新生小鼠辣椒素处理在发育过程中影响小梁骨;然而,在正常负荷条件下,这些微小变化可能对骨强度没有意义。在诸如机械负荷增加或受伤等应激条件下,辣椒素敏感神经元对骨可能更为重要。未来的研究将探讨外周感觉神经在骨适应中的这一潜在作用。