兔股骨干缺损模型的制备及在组织工程骨实验中的应用

目的为组织工程骨修复负重骨缺损的研究提供标准化的实验动物模型.方法测量兔股骨干基本解剖数据,用于指导制备模型.在解剖学研究的基础上,取4～5个月龄成年新西兰大白兔18只,随机分为三组,每组6只,分别制备10、15、20mm的股骨干中段骨和骨膜缺损,并用普通钢板螺丝钉固定股骨.4、8、12周时分别摄X线侧位片进行定性分析,双能量X线骨密度测量仪（DXA）做骨密度扫描进行定量分析,并在每个时间点分别取2只动物取材做大体观察和组织学检查.结果兔股骨解剖数据：兔股骨长94.1 mm;股骨干中点横径7.4 mm,矢状径5.8 mm;骨皮质厚度：屈侧最厚,内、外两侧次之,伸侧最薄,平均1.2 mm;髓腔略呈椭圆形,其横径与矢状径相差约1mm,取其平均值,髓腔直径4.1 mm.骨缺损动物大体观察、X线片、骨密度检查和组织学检查显示：10 mm骨缺损组均于8～12周出现骨性愈合;15 mm和20 mm骨缺损组直至12周仍未见骨愈合.结论在不桥接和填充任何材料的情况下,钢板螺钉固定的兔股骨干15 mm以上的实验性骨缺损不能自行愈合,可用于组织工程骨修复负重骨缺损的实验研究.

An experimental model of bone defect at the rabbit femoral shaft to be used in bone tissue engineering research

Objective To set up a standard experimental model of defect at rabbit femoral shaft which can not heal up spontaneously. Methods Anatomic data of rabbit femur were obtained through measurement in order to guide the operation. Then bone defects of 10, 15, and 20 mm were made respectively in the femoral shafts of 18 grown New Zealand rabbits. The defects were fixed by common plates. Radiography, DXA (Dual Energy X-ray Absorptiometry), general observation and histology were undertaken to examine bone formation at time points of 4, 8, 12 weeks. Results The rabbit femur had a length of 94.1 mm. At the midpiece of the rabbit femoral shaft, the transverse diameter was 7.4 mm and the sagittal diameter 5.8 mm. At the same place, cortical bone was the thickest at the posterior side and the thinnest at the anterior. The thickness of 2 lateral sides was between the 2 extremes above. The average thickness of cortical bone was 1.2 mm. The average diameter of the medullary cavity was 4.1 mm while the sagittal diameter was 1.0 mm less than the transverse one. The bone defects in the 10 mm group of rabbit femoral shaft healed up in 8 to 12 weeks. No recovery of bone defect in the 15mm group was seen after 12 weeks as not in the 20 mm group. Conclusions Bone defects of 15 mm and more in rabbit femoral shaft can not heal up spontaneously. Consequently, this critical-sized segmental bone defect model may be used for the research of bone tissue engineering.