Hiltunen A, Vuorio E, Aro H T
Department of Surgery, University of Turku, Finland.
J Orthop Res. 1993 Mar;11(2):305-12. doi: 10.1002/jor.1100110219.
The increased use of transgenic mice as experimental animals provides new opportunities to study the biology of fracture repair. We have developed a technique for the production of a standard closed experimental fracture in the mouse tibia. A 0.2 mm stainless-steel rod was introduced into the medullary cavity and the pre-nailed tibial shaft was fractured by an impact device, which resulted in a reproducible transverse or slightly oblique fracture pattern. The intramedullary rod maintained axial alignment, and the fractures united without displacement. On the basis of measurements of callus geometry, four-point bending tests, biochemical analyses, and quantitative histology, the progress of callus formation and remodeling occurred in a predictable sequence of healing phases. The ultimate bending loads of the fractures increased with time, reaching 74% of the strength of intact control tibias in 4 weeks. The stiffness values of the fractures returned to normal levels and, as determined radiographically, the fractures united by external callus in 4 weeks. Radiographically, callus size, cross-sectional callus area, and callus mass peaked at 2 weeks and decreased thereafter, indicating the start of external remodeling. Histologically, the amount of mesenchymal tissue was maximal at days 5 and 7. The callus cartilage area peaked at day 9; at its maximum, it accounted for 46% of the total callus area. Early periosteal formation of membranous new bone, followed by endochondral ossification, resulted in a linear increase of callus bone during the healing process. The healing sequence of the mouse tibial fracture was similar to that seen in the rat tibia.(ABSTRACT TRUNCATED AT 250 WORDS)
转基因小鼠作为实验动物的使用增加，为研究骨折修复生物学提供了新机会。我们已开发出一种在小鼠胫骨上制造标准闭合性实验性骨折的技术。将一根0.2毫米的不锈钢棒插入髓腔，并用冲击装置使预先钉入的胫骨干骨折，从而产生可重复的横行或轻微斜行骨折模式。髓内棒保持轴向对齐，骨折无移位愈合。基于对骨痂几何形状的测量、四点弯曲试验、生化分析和定量组织学，骨痂形成和重塑的进展按可预测的愈合阶段顺序发生。骨折的极限弯曲载荷随时间增加，4周时达到完整对照胫骨强度的74%。骨折的刚度值恢复到正常水平，通过X线检查确定，骨折在4周时通过外骨痂愈合。X线检查显示，骨痂大小、骨痂横截面积和骨痂质量在2周时达到峰值，此后下降，表明开始进行外部重塑。组织学上，间充质组织量在第5天和第7天最大。骨痂软骨面积在第9天达到峰值；在其最大值时，占骨痂总面积的46%。早期骨膜形成膜性新骨，随后进行软骨内成骨，导致愈合过程中骨痂骨线性增加。小鼠胫骨骨折的愈合顺序与大鼠胫骨相似。（摘要截短至250字）
