感觉/运动神经切断影响大鼠骨折愈合的实验研究

Experimental evaluation of the fracture healing of rats following sensory nerve/motor nerve radicotomy

[目的]通过建立切断组成大鼠坐骨神经的不同成分、联合胫骨骨折的动物模型,来研究感觉/运动神经损伤对骨折愈合的影响,并进一步探讨周围神经系统对骨组织的生理作用。[方法]Wistar大鼠90只平均分为3组:对照组,运动神经(前根)切断组,感觉神经(后根)切断组,选择性切断一侧L4～6神经根。所有大鼠于神经根暴露侧/切断侧胫骨造成横行骨折,髓钉固定。30d后取大鼠双侧胫骨,测患侧胫骨近端骨密度、在影像学资料上测量患侧骨痂宽度及健侧胫骨相应位置的皮质宽度、取所有大鼠双侧胫骨行湿重称量、骨痂组织学切片观察、双侧胫骨行生物力学拉伸测试。所得结果均以患侧数据除以相应健侧数据得出一相对数,以相对数数据进行统计分析。[结果]患侧胫骨近端骨密度无显著差异(P>0.05);检测项目示神经切断组骨折处骨痂形成多,力学强度差,骨痂成熟度差(P<0.05),以感觉神经(后根)切断组尤甚(P<0.05)[结论]感觉神经纤维对骨折愈合的影响较运动神经纤维显著;完整的神经支配是正常骨折愈合的必要条件。

[Objective]To observe and analyze the effect of selective radicotomy on the fracture healing by selective nerve root rhizotomy.[Method]Ninety rats were divided into three groups randomly, incluing the sham operate group （SO）,the anterior rhizotomy group（ART） and the posterior rhizotomy group（PRT）. All rats were made experimental tibial transverse fracture at nerve-cut side and the fracture was fixed with intramedullar nail.In coordination with the fracture-tibia side,the rats were made with selective radicotomy from L4 to L6. Animals were sacrified after 30 days and tension-test of every pair tibia was recorded by Instron5050 electrical univerials tester to evaluate the mechanical properties of bony callus. The BMD was measured in proximal end of every fracture-tibia and the size of bony callus was evaluated by wet weight and radiograph. The callus property was monitored by histological assessment.All data of fracture side were divided by uninjured-side to get the ratio for evaluation for every pair of tibia. [Result]There was no statistical significance about the BMD of the fracture-tibia between the SO group and the other groups（P〉0.05）.The data of wet weight and radiograph of fracture-tibia showed an increased callus formation, but result of tension-test indicated strength of bony callus were decreased and weaker in all denerved groups（P〈0.05） and more marked in PRT group（P〈0.05）.[Conclusion]The sensory nerve could show more important role than the motor nerve during the bone fracture healing and normal innervation is essential while nerve injury could make the callus large,but mechanically insufficient.