环形外固定架联合骨膜烧灼构建大鼠胫骨萎缩性骨不连的新模型

Establishing a rat model of atrophic nonunion by using circular external fixator combined with periosteum cauterization

背景:建立标准萎缩性骨不连动物模型是研究萎缩性骨不连的发生机制与治疗的必要条件,而目前常见的造模方法不能准确模拟萎缩性骨不连的临床实际。目的:构建一种新型萎缩性骨不连动物模型。方法:30只雄性SD大鼠随机分成实验组和对照组,均行右侧胫骨中下段截骨,采用环形外固定架固定,维持4 mm缺损间距;其中实验组烧灼截骨端周围1 mm骨膜,对照组不处理骨膜。实验于2018-01-02经广州中医药大学第一附属医院实验动物伦理委员会批准,批号:TCMF1-2018002。结果与结论:造模后每组分别出现1例外固定架松动,2组均未发生感染;影像学检查显示造模后6周,2组胫骨骨折断端间均无骨性连接,且无进一步愈合迹象;实验组第12周时影像学与组织学显示呈典型萎缩性骨不连表现;对照组第12周影像学显示8只模型呈现肥大性骨不连特征,6只模型影像学具有萎缩性骨不连特征。提示采用环形外固定支架配合烧灼断端骨膜可成功构建萎缩性胫骨骨不连模型。

BACKGROUND:Establishment of a standard experimental animal model of atrophic nonunion is necessary for experimental study and related treatment of atrophic nonunion.However,the common modeling methods cannot accurately simulate atrophic nonunion in the clinical practice.OBJECTIVE:To construct a standard animal model of atrophic nonunion.METHODS:Thirty male Sprague-Dawley rats were randomly divided into experimental and control groups.All animals were subjected to bone cutting at the middle-lower segment of the right tibia and the circular external fixator was applied to keep a 4 mm defect interval.The animals in the experimental group were subjected to an additional cauterization of the periosteum at the fracture end of the tibia with a length of 1mm.The periosteum was not treated in the control group.The study protocol was approved by the Experimental Animal Ethics Committee of the First Affiliated Hospital of Guangzhou University of Chinese Medicine on January 01,2018,with approval No.TCMF1-2018002.RESULTS AND CONCLUSION:After modeling,there was one case of loose external fixation in each group,and no infection occurred in both groups.Imaging examination showed no bone connection and no sign of healing between the fractures of the tibia in the two groups at 6 weeks after modeling.Imaging and histological findings showed no healing at the end of fracture but typical atrophic nonunion in the experimental group at 12 weeks after modeling.By contrast,six animals had atrophic nonunion,and eight had hypertrophic nonunion in the control group.Overall,the animal model of atrophic tibial nonunion can be successfully constructed using circular external fixator combined with periosteal cauterization at the fracture end.