Experimental research on the development of a new therapy for bone injury via sympathetic nerve system

骨折治疗后术后早期下床活动可有效减轻废用介导的骨萎缩，从而防止老年人卧床不起或骨质疏松，并有助于青少年骨骼健康发育，降低未来骨质疏松的风险。在这项研究中，我们研究了通过β-肾上腺素能系统治疗骨折的潜力，特别是在愈合的早期阶段。在麻醉大鼠中，在胫骨骨干处形成全层单皮质缺损，并通过尾部悬吊实现后肢卸载。这些动物被分成三组：不给药(C)，用心得安阻断β-肾上腺素能（PRO），用去铁胺促进血管生成。缺损术后5天或10天后，腹腔主动脉注射氧化锆琼脂糖造影剂。然后切除缺陷区，用同步加速器扫描。1和18。1 keV用于减法CT，分别位于氧化锆k边缘的正下方和上方。重建图像被分割成骨骼和血管。术后5天，DFO组新生血管体积分数明显高于c组，而PRO组只有高于c组的趋势。两种治疗方法在此阶段对骨再生没有影响。术后10 d，三组血管新生进展程度相似；然而，DFO组再生骨的体积分数明显高于PRO组，而PRO组只倾向于高于c组。β-肾上腺素能阻滞剂的有效浓度或选择性需要进一步研究，以便更好地利用它们。

Early postoperative ambulation after fracture treatment is effective in mitigating disuse-mediated bone atrophy, thereby preventing elderly persons from a bedridden state or osteoporosis and assisting healthy bone development of juveniles to reduce the future risk of osteoporosis. In this study, we examined a potential of fracture treatment throughβ-adrenergic system, especially in the early stage of healing. In anesthetized rats, a full thickness unicortical defect was created in a tibial diaphysis, and hindlimb unloading was achieved through tail suspension. The animals were grouped into three categories : rats treated with none(C), with propranolol forβ-adrenergic blockade(PRO), and with desferrioxamine for the enhancement of angiogenesis. Five or ten days later the defect surgery, the animals were injected with zirconia-agarose contrast medium from the abdominal aorta. Then the defect region was cut out and scanned with synchrotron light with 17. 1 and 18. 1 keV for subtraction CT, immediately below and above the zirconia k-edge, respectively. Reconstructed images were segmented into bone and blood vessels. Five days after surgery, volume fraction of newly formed vessels was significantly higher in DFO but only tended to be higher in PRO than that in C. Both treatments had no effect on bone regeneration at this stage. Ten days after surgery, angiogenesis advanced to the similar degree in three groups ; however, volume fraction of regenerated bone was significantly higher in DFO but only tended to be higher in PRO than that in C. Further studies on the effective concentration or selectivity ofβ-adrenergic blockers are needed for their beneficial utilization.