Biomechanical Response of Bone to the Cessation of Exercise: Development ofa Mechanical Test Apparatus for Trabecular Bone

骨骼对运动停止的生物力学反应：骨小梁力学测试装置的开发

• 批准号: 13680937
• 负责人: FUJIE Hiromichi
• 金额: $ 2.37万
• 依托单位: Kogakuin University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13680937/
• 关键词: Cessation of exercise; Bone remodeling; Cortical and trabecular bones; Morphological analysis; Mechanical property; Bending test; 皮質骨; 海綿骨; リモデリング; 運動負荷停止; 構造強度; 材料強度; 異方性; ラット

It is crucial for clinical orthopaedic surgery to determine the response of bone to the cessation of exercise, because such a change in load condition normally happens in daily lives. It is also important for basic biomechanic's and engineering design to understand the mechanism of the response. Previous studies have shown that the mechanical properties of the tibia from immature rats were improved by running. In addition, the improved properties remained unchanged after the return of load to normal. The present study was performed to know whether the same phenomena were observed also in mature ratsSixteen-week-old mature Wistar female rats were divided into running (Run), running and sedentary(Run/Sed), and Control groups. The rats of Run group were subjected to 1.6 km/h, 1 hour-a-day, 6 days-a-week treadmill running program for up to 15 weeks. The rats of Run/Sed group,were subjected to the same running program for up to another 15 weeks. Control group rats were subjected to normal u … More nrestricted activities throughout experimental periods. After sacrifice, compression and hardness tests were performed on the specimens obtained from the midshaft of each tibia. The microstructure of the proximal tibia was also observed using an X-ray μCT system. Compressive load at failure was lower in Run group at 3 weeks as compared with that in Control group, although it increased to a control level at 15 weeks. Micro Vickers hardness in Run and Run/Sed groups was slightly higher than that in Control group. The areas of cortical and trabecular bones were smaller in Run group than those in Control group. After the cessation of running, the area of trabecular bone was remained smaller even at 30 weeks; however, the area of cortical bone increased to a control level at 30 weeks. For the evaluation of the mechanical property oftrabecular bones, a bending test apparatus was designed and developed. The edge parts of the apparatus which contact with the trabecular bone in bending test were consisted of stainless steel (SUS304), and a ring-shaped load transducer was consisted of aluminum alloy. A preliminary test for a pig tibia revealed that it was possible to perform three-point bending test using the developed apparatus. The elastic modulus of the trabecular bone was approximately 72 MPa in proximal areaIn summary, in mature rat tibiae the material properties were slightly increased, and the structural properties were slightly decreased by running for 15 weeks. The material properties were unchanged after the activity change to sedentary state. It is possible using the developed apparatus to perform the three-point bending test for the trabecular bones. This technique will be used in further studies on bone remodeling Less

确定骨骼对运动停止的反应对于临床骨科手术至关重要，因为这种负荷条件的变化通常发生在日常生活中。了解响应机制对于基础生物力学和工程设计也很重要。先前的研究表明，未成熟大鼠胫骨的机械性能通过跑步得到改善。此外，负载恢复正常后，改进的性能保持不变。本研究旨在了解在成熟大鼠中是否也观察到相同的现象。将16周龄的成熟Wistar雌性大鼠分为跑步组(Run)、跑步和静坐组(Run/Sed)以及对照组。跑步组大鼠接受1.6公里/小时、每天1小时、每周6天的跑步机跑步计划，持续长达15周。 Run/Sed组的大鼠再接受相同的跑步计划长达15周。对照组大鼠在整个实验期间进行正常和限制的活动。处死后，对从每个胫骨中轴获得的样本进行压缩和硬度测试。还使用X射线μCT系统观察了近端胫骨的微观结构。与对照组相比，运行组在第 3 周时失败时的压缩负荷较低，但在第 15 周时增加至对照组水平。 Run组和Run/Sed组的显微维氏硬度略高于对照组。跑步组皮质骨和骨小梁面积均小于对照组。停止跑步后，骨小梁面积在30周时仍然较小；然而，皮质骨面积在 30 周时增加至对照水平。为了评价骨小梁的力学性能，设计并研制了弯曲试验装置。弯曲试验中与骨小梁接触的装置边缘部分由不锈钢(SUS304)制成，环形负载传感器由铝合金制成。对猪胫骨的初步测试表明，使用所开发的设备可以进行三点弯曲测试。近端区域骨小梁的弹性模量约为72 MPa。综上所述，在运行15周后，成熟大鼠胫骨的材料性能略有增加，而结构性能略有下降。活动状态转变为静止状态后，材料性能没有变化。使用所开发的设备可以对骨小梁进行三点弯曲测试。该技术将用于骨重塑的进一步研究 Less

项目成果

Fujiwara,T, Morimoto,T, Fujie,H, Hayashi,K: "Response of matured rat femur to the change of mechanical load"Abstract of the 28th annual meeting of the Japanese Society for Clinical Biomechanics and Related Research. 127 (2001)

Fujiwara,T, Morimoto,T, Fujie,H, Hayashi,K：“成熟大鼠股骨对机械负荷变化的反应”日本临床生物力学及相关研究学会第 28 届年会摘要。

藤原泰介, 森本 尚, 藤江裕道, 林 紘三郎: "力学的負荷の変化に対する成熟ラット大腿骨の反応"第28回日本臨床バイオメカニクス学会抄録. 127 (2001)

Taisuke Fujiwara、Takashi Morimoto、Hiromichi Fujie、Kozaburo Hayashi：“成年大鼠股骨对机械负荷变化的反应”第 28 届日本临床生物力学学会摘要 127 (2001)。

Fujie,H, Suzuki,Y, Ota,M, Mabuchi,K: "Coefficient of start-up friction of early stage osteoarthritic cartilage is not larger than normal cartilage"Advances in Bioengineering (ASME). BED-53 IMECE. 2002-32607 (2002)

Fujie,H, Suzuki,Y, Ota,M, Mabuchi,K：“早期骨关节炎软骨的启动摩擦系数不大于正常软骨”生物工程进展 (ASME)。

Fujie, H., Suzuki, Y., Ota, M., Mabuchi, K.: "Coefficient of start-Up Friction of Early Stage Osteoarthritic Cartilage is not Larger Than Normal Cartilage"Advances in Bioengineering (ASME). BED-53. IMECE2002-32607 (2002)

Fujie, H.、Suzuki, Y.、Ota, M.、Mabuchi, K.：“早期骨关节炎软骨的启动摩擦系数不大于正常软骨”生物工程进展 (ASME)。

藤原泰介, 森本 尚, 藤江裕道, 林紘三郎: "力学的負荷の変化に対する成熟ラット大腿骨の反応"第28回日本臨床バイオメカニクス学会抄録. 127 (2001)

Taisuke Fujiwara、Takashi Morimoto、Hiromichi Fujie、Kozaburo Hayashi：“成年大鼠股骨对机械负荷变化的反应”第 28 届日本临床生物力学学会摘要 127 (2001)。