大鼠失神经骨折愈合中骨痂体积与生物力学强度的相关性分析

Correlation between the volume and the mechanical properties of pathological bony callus in fracture healing of denervated rats

目的探讨失神经骨折愈合中病理性骨痂的体积与力学强度的相关性。方法Wistar大鼠90只随机分为3组,每组30只:运动神经(前根)切断组、感觉神经(后根)切断组、前后根切断组,均选择性切断一侧L4-L6神经根。所有大鼠于神经根切断侧胫骨造成横行骨折,髓钉固定。30d后取大鼠患侧胫骨,测胫骨近端骨密度、胫骨湿重称量、在X线片上测量骨痂宽度、胫骨进行生物力学拉伸测试,SPSS统计数据。结果患侧胫骨近端骨密度三组间比较无统计学差异(P>0.05),病理性骨痂其体积与生物力学强度呈负相关(P<0.05),以涉及感觉神经(后根)损伤组尤甚(P<0.05)。结论失神经骨折愈合中所形成的病理性骨痂其体积与生物力学强度呈负相关,感觉神经纤维对骨折愈合的影响较运动神经纤维显著。

Objective To explore the correlation between the volume and the mechanical properties of pathological bony callus of denervated fracture healing.Methods Ninety Wistar rats were randomly divided into three groups：anterior rhizotomy group（ART,n=30）,posterior rhizotomy group（PRT,n=30）and radicotomy group（RT,n=30）.Tibial transverse fracture of all rats were made at nerve-cut side and then fixed with intramedullary nail.At the fracture-tibia side,the rats were inflicted with the selective radicotomy from L4 to L6.Animals were executed after 30 d and tension-test of every pair tibia was recorded by Instron5050 electrical universal tester to evaluate the mechanical properties of bony callus.Bone mineral density（BMD）was measured at proximal end of every fracture-tibia and the volume of bony callus was evaluated by wet weight and radiograph.Results BMD of the fracture-tibia had no significant difference between all groups（P〉0.05）.The wet weight and radiograph of fracture-tibia showed an increasing callus formation.The mechanical properties of bony callus were weaker in all denervated groups,and they were stronger in PRT and RT groups than in ART group（P〈0.05）.The volume of callus was negatively correlated with the mechanical properties of pathological bony callus（P〈0.05）.Conclusion The results indicate that the sensory nerve could be more important than the motor nerve during the bone fracture healing.