微型外固定器制作大鼠股骨萎缩型骨不连模型的实验研究

目的 探讨以自行研究设计的微型外固定器建立股骨萎缩型骨不连动物模型。方法 以自行研究设计的外固定器为固定装置，选取24 只健康雄性Lewis大鼠，随机分为2组：骨不连组和对照组，每组12只。于大鼠右侧股骨截骨，在2个断端之间留1 mm间隙，于股骨前外侧面近端放置一对自攻螺纹钉，同样方法，在远端放置另一对自攻螺纹钉。其中骨不连组去除骨髓和破坏骨膜，对照组不进行此操作。术后2、4、8周影像学观察股骨对位情况、外固定器的位置及截骨区的愈合情况。术后8周取材行组织学检查和生物力学检测。结果 术后8周时X线片示：对照组骨断端已愈合，髓腔再通；骨不连组骨断端处无连续性骨痂通过，骨断端清晰可见。组织学检查显示：对照组有大量新骨形成，骨断端与正常骨无差异；骨不连组截骨区无骨性连接，截骨端未愈合。8 周时生物力学检测显示：对照组的扭转刚度平均为(2.64±0.40)N·mm/deg，骨不连组为(0.21±0.20)N·mm/deg,差异有统计学意义（t=16.168,P=0.000）。结论 本实验研究为组织工程及细胞生物技术治疗萎缩型骨不连的研究提供了一种可靠的动物模型。

A rat model of femoral atrophic nonunion made with a miniature external fixator

Objective To design an animal model which can be used for research on bone atrophic nonunion.Methods A new external fixator was developed as fixation device for the present experiment.Of the 24 male Lewis rats that underwent femoral osteotomy at the right hind limb, 12 were randomly assigned to an atrophic nonunion group, in which cauterization of the periosteum and removal of the local bone marrow were performed, and 12 to a control group. Radiological examinations were conducted 2, 4 and 8 weeks postoperatively to observe femoral alignment, position of the external fixator, and healing at the osteotomy site.Histological and biomechanical observations were performed 8 weeks postoperatively.Results At 8 weeks postoperatively, radiological analyses showed a typical physiological healing in the control group, while the atrophic nonunion group was characterized by absence of continuous callus and clear fracture ends. Histological examinations revealed no bony union or healing at the osteotomy site in the atrophic nonunion group but massive new bone formation in the control group. Biomechanical tests showed the torsional strength of the osteotomized femur was significantly smaller in the nonunion group(0.21 ±0. 20 N · mm/deg) than in the control group(2.64 ± 0.40 N · mm/deg) ( t = 16.168, P = 0.000) .Conclusion The animal model created in this experiment can be used for research on treatment of bone atrophic nonunion with tissue engineering and cyto-biological technology.