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

点击翻译按钮获取中文摘要

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.