异位骨化预防性放疗对骨折愈合影响的实验研究

The effect of heterotopic osteogenesis preventive radiation on fracture healing: An animal model study

目的探索骨折后48h给予单次放疗预防异位骨化的同时对骨折愈合造成的影响,并将其用于创伤骨折初期预防异位骨化的可能性。方法取成年SD大鼠50只,随机分成5组,制成双侧股骨骨折模型,实验侧骨折后48h予放疗,对侧为对照侧。分别于骨折后2周、4周、8周、12周、16周取双侧股骨,进行放射学,组织学和生物力学评估骨折愈合情况。实验还采取实验侧伤口旁皮毛和部分股四头肌组织作组织学观察。结果骨折后4周时实验侧骨痂厚度明显小于对照侧(<0.05),其余各组双侧无显著性差异;骨组织切片观察发现骨折2周组中实验侧的股骨愈合的组织学评分显著低于对照侧(<0.05),其余各组双侧无显著性差异;生物力学测试,4周组大鼠的实验侧股骨最大弯曲载荷显著低于对照侧(<0.05),其余各组双侧无显著性差异。结论用于预防异位骨化的单次小剂量放疗的确在早期抑制了骨折修复,骨折都是会逐步愈合,只是愈合的时间相对延长。这种放疗对皮肤伤口愈合,毛发生长,骨周围软组织无明显损害。临床应用尚需进一步论证。

Objective To investigate the effect of a single heterotopic osteogenesis preventive radiation administered 48h after fracture on its healing, and to assess the possibility of its application in the early management of susceptible fractures. Methods 50 adult SD rats were randomly devided into 5 groups which were to sacrifice in 2, 4, 8, 12, 16 weeks repectively. Both their femurs were osteotomized and fixed with intramedullar pins, one side was irradiated 48h later, the other was reserved as control. In due time, both femurs were harvested for radiological, histological and biomechanical study of fracture healing. The fur and part of the quadriceps femoris on the irradiated side were also collected for histological study Results The callus on the irradiated side is significantly less than that on the control side in the 4 weeks group （P〈0.05）, the differences between both sides in the other groups are insignificant, which remains the same with the maximum load in the biomechanical test. The histological scoring of the irradiated side in the 2 weeks group is significantly less than the control side（P〈0.05）, the differences between both sides in the rest groups are insignificant. Conclusion The preventive dose of radiotherapy against heterotopic osteogenesis does inhibit fracture healing in the early stage, nonetheless, the healing process continues at a slower rate and will finally heal. This amount of radiation has no discernible harm to the wound healing, hair growth and musculature. However, further study should be conducted before clinical application.