大鼠股骨骨折愈合中双能X线吸收法和组织学观察

目的 动态观察大鼠骨折愈合过程中骨折端的骨密度和组织学变化,探讨双能X线吸收法(DEXA)监测骨折愈合的作用。方法 60只3月龄,雌性SD大鼠,手术方法建立右股骨骨折模型,于术后2、4、6、8、10、12周截取双侧股骨。用双能X线吸收法作骨折端和干骺端骨密度测定,对侧股骨相同位置测量以作对照。同时对骨折端骨痂进行组织学观察。结果 骨折端平均骨密度值随时间变化递增,显示了一个明确的骨折愈合趋势。术后2、4、6、8周时分别为对侧股骨相应区域的29．5％、48．3％、85．3％、105．2％,各组差异明显。骨密度值的升高与骨痂组织的产生、钙化在时间上有一致性。干骺端骨密度在术后持续降低,到12周时尚未见回升迹象。结论 骨折端的骨密度变化与骨折端骨痂的组织学变化有一致性,骨密度能准确、定量地反映骨痂组织的钙化程度。用DXEA监测骨折愈合具应用前景。

The observation of bone mineral density by dual energy X-ray absorptiometry and histology during fracture healing at the femoral fracture site of rat

OBJECTIVE: To dynamically observe the bone mineral density and histology changes during fracture healing at the femoral fracture site, and to study the role of monitoring fracture healing by dual energy X-ray absorptiometry (DEXA). METHODS: 60 female 3-month-old SD rats were used to establish right femoral fracture model. The fractured and contralateral unfractured femorals were scanned by Dual Energy X-ray absorptiometry in 2, 4, 6, 8, 10 and 12 weeks postoperatively. The callus of each rat was examined by light microscope at the same time. RESULTS: The value of bone mineral density at rat femoral fracture site was significantly increased post-osteotomy, showing a clear healing trend. The bone mineral density at fracture site was 29.5%, 48.3%, 85.3%, 105.2% of the value obtained of the control limb 2, 4, 6 and 8 weeks postoperatively. There was a compatibility on time between bone mineral density and histology. The BMD of distal metaphysis remained reduced until 12 weeks. CONCLUSION: The change of bone mineral density at the fracture site exhibited positive correlation with the histology of fracture healing, bone mineral density can accurately quantify the extent of mineralization of callus at the fracture site. DEXA can be used as a new technique in monitoring fracture healing.