一种应力性骨折动物模型构建新装置的研制

Development of new loading device for establishment of stress fracture animal models

目的:设计一种载荷定量、精确、可控的应力性骨折动物模型构建新装置。方法:采用轴向周期性压缩加载的方法设计,整个装置由应力加载装置、线性促动器控制模块和数据实时采集与处理模块组成,其中应力加载装置主要由线性促动器、应力传感器、线性导轨、组织固定模块(包括动夹头和定夹头)和位移传感器组成。采用峰值压力为50 N的周期性压缩加载实验来检验该装置工作的可靠性,并使用该装置和Electro Force 3220万能材料试验机测量超高分子量聚乙烯(ultra-high molecular weight polyethylene,UHMWPE)小圆柱体标准材料的杨氏模量,通过对比来进行标定。结果:该装置可施加强度可控、时间可控、模式一致的周期性载荷,能够建立大鼠尺骨和胫骨2种应力性骨折动物模型,且工作准确性高。结论:该装置具有精确、科学和可靠的特点,所构建模型接近真实应力性骨折发生的情况,可为研究应力性骨折的发病机制、探索有价值的预防和治疗方法提供重要的动物模型平台支持。

Objective To develop a novel stress fracture animal model system based on dynamic cyclic mechanical loading.Methods Ulnae and tibiae of rats were respectively fixed using differently shaped fixtures（including a fixed holder and a movable holder）.The axial mechanical loading was applied via a linear actuator based on Lab VIEW control program.During the loading process,a load cell and a laser displacement transducer were used to detect the force and displacement changes in the limbs,respectively.The two signals were sampled at real time by PC-based Lab VIEW data acquisition program.A compressive loading test（peak force of 50 N）was conducted to examine the consistency and reliability of cyclic loads after completing the loading system.The loading system and an Electro Force 3220 mechanical testing machine were respectively used to measure and compare the Young＇s modulus of a standard ultra-high molecular weight polyethylene（UHMWPE）cylinder to calibrate the loading system.Results The compressive loading test（peak force of 50 N）demonstrated that the mechanical loading system was able to apply consistent loads with controllable intensity and time.The calibration experiment indicated the accuracy of the loading system.Conclusion The novel mechanical loading device has characteristics of precision,scientificity and reliability,and it is approaching the real development situation of stress fracture,which may provide a reliable experimental base for exploring the precautionary measures of stress fracture.