持续与间歇低载荷振动对骨折愈合影响的实验研究及计算机模拟

The purpose of the subject is to explore the function and the mechanism of continuous or intermittent high frequency and low magnitude whole body vibration, with frequency of 35 Hz and acceleration of 0.25g, in fracture healing by animal experiments or cell culture in vitro. There is sensitivity fatigue of bone cell after a long period of continuous vibration. Therefore, intermittent mechanical loading may provide a better efficacy in bone healing because the mechanical sensitivity to stress and acceleration could recover during the interval days. Tibial fracture was established by osteotomy. All the sheep were subjected to continuous or intermittent high frequency and low magnitude whole body loading after internal fixation on tibia by limited contact dynamic compress plate. The microstructure, biomechanics and expression of bone morphogenetic protein were tested, which may play important roles in bone healing. In addition, bone marrow derived mesenchymal stem cell, osteoblast and bone cell were loaded by continuous or intermittent vibration in vitro to study the signal transduction, genetic transcription and protein expression, which may reveal the osteogenetic mechanism of this mechanical regime in cell level. Finally, this procedure was simulated by computer finite element analysis. The aim of all the tests is to explore a non-invasive and non-pharmacal regime in bone healing.

通过实验动物和体外培养的骨系细胞加以低载荷机械振动（35Hz，0.25g），探索持续与间歇式低载荷机械振动对骨折愈合的影响及作用机理。由于骨细胞存在敏感疲劳，间歇的振动模式有助于恢复骨细胞对应变及加速度的敏感性，获得更好的成骨效果。首先手术构建长骨骨折模型，给与有限接触动力加压钛合金钢板内固定，后施加以持续性和间歇性的低载荷振动垂直作用于骨折肢体，观测骨形态结构和力学性能的变化，以及骨折微环境中蛋白质表达水平的改变，探讨振动对骨折愈合过程的影响；另外，给与体外培养的骨髓间充质干细胞、成骨细胞和骨细胞施加持续与间歇的低载荷机械振动，研究其细胞信号转导，基因转录及蛋白质表达的情况，在细胞水平上探索低载荷机械振动促进骨生长的机理；最后，利用数值模拟技术进行计算机模拟，并对低载荷振动对促进骨折愈合的作用进行模拟验证。探索一种非侵入性、非药物的促进骨折愈合方法，为广大骨折患者作出一份贡献。

通过实验动物和体外培养的骨系细胞加以低载荷机械振动（35Hz，0.25g），探索持续与间歇式低载荷机械振动对骨折愈合的影响及作用机理。由于骨细胞存在敏感疲劳，间歇的振动模式有助于恢复骨细胞对应变及加速度的敏感性，获得更好的成骨效果。首先手术构建长骨骨折模型，给于钢板内固定，后施加以持续性和间歇性的低载荷振动垂直作用于骨折肢体，观测骨形态结构和力学性能的变化，以及骨折微环境中蛋白质表达水平的改变，探讨振动对骨折愈合过程的影响，另外，给予体外培养的骨髓间充质干细胞、成骨细胞和骨细胞施加持续与间歇的低载荷机械振动，研究其细胞信号转导、基因转录及蛋白表达的情况，在细胞水平上探索低载荷机械振动促进骨生长的机理；最后，我们利用数值模拟技术进行计算机模拟，得出结论，持续与间歇低载荷机械振动能够促进骨折愈合。不同间歇周期的间歇性机械振动促进骨折愈合的效果不同，最好的振动周期是振动7天，间歇7天。