脊神经节节前或节后切断影响大鼠骨折愈合的实验研究

Effect of selective sensory radicotomy before or after the ganglion on tibia fracture healing

目的通过建立大鼠一侧脊神经后根神经节节前/节后切断、联合同侧胫骨骨折的动物模型，观察骨折愈合过程，评价脊神经节对骨折愈合的影响。方法自2014年9月-2015年8月，将120只大鼠平均分为3组：单纯手术组（SO组）、脊神经后根节前切断组（AGR组）和脊神经后根节后切断组（PGR组），每组40只。切断范围包括L4~L6神经根。将神经切断侧胫骨造成横断骨折模型。术后3 d、7 d和2周时，每组分别处死5只大鼠，取骨折处骨痂组织，应用RT-PCR技术检测I型胶原和II型胶原的mRNA表达情况。于术后4周和8周时，每组分别处死5只大鼠，对骨折处骨痂组织进行组织学观测。使用影像学方法在术后4周和8周对所有大鼠进行骨折愈合情况观测。所有数据采用相对数（骨折侧数据/健侧数据）进行统计学分析。结果在术后3 d和7 d时，骨折端骨痂组织中I型胶原和II型胶原mRNA的相对表达量方面，SO组[I型胶原分别为（81.3±11.1）倍、（17.9±5.8）倍；II型胶原为（2.4±0.5）倍、（12.5±3.4）倍]较其他两组[AGR和PGR组I型胶原3 d时分别为（37.5±8.2）倍、（24.7±9.2）倍，7 d时分别为（7.2±1.8）倍、（6.7±2.4）倍；II型胶原3 d时分别为（2.1±1.0）倍、（2.9±1.2）倍，7 d时分别为（2.8±1.3）倍、（1.2±0.4）倍]明显增高（P〈0.05），而术后7 d时II型胶原mRNA的相对表达量方面AGR组（2.8±1.3）较PGR组（1.2±0.4）增高（P〈0.05）。术后4、8周，AGR组和PGR组比SO组骨折端局部骨痂体积大，矿化程度低，力学载荷低（P〈0.05），尤以PGR组明显（P〈0.05）。结论感觉神经损伤影响骨折愈合的过程，而感觉神经根上的脊神经节对骨折愈合可能也起重要作用。

ObjectiveTo analyze the effect of the fracture healing by using selective sensory radicotomy before and after the ganglion.MethodsFrom September, 2014 to August, 2015 , 120 rats were averagely divided into 3 groups, which was the sham operate group （SO） , the anterior injury of ganglion rhizotomy group （AGR） and the posterior injury of ganglion rhizotomy group （PGR） . Tibial transverse fracture was performed on right or left randomly and the fracture was fixed with intramedullary. In coordination with the fractured- side, the selective radicotomy from L4 to L6 was made. The mRNA level of collagen-I and collagen-II in bony callus was quantified at 3, 7 days and 2 weeks after the operation by RT-PCR （n=5） . The histological examination, X-ray, biomechanical testing were performed at 4 and 8 weeks. The quantitative data of iconography and biomechanics was acquired by using the relative ration which resulted from fractured-side data dividing the unfractured-side one for every pair tibia in same rat.ResultsAt 3 days after surgery, the mRNA of collagen-I were 81.3±11.1, 37.5±8.2 and 24.7±9.2, the mRNA of collagen-Ⅱwere 2.4±0.5, 2.1±1.0 and 2.9±1.2 in SO, AGR and PGR group respectively; At 7 days after surgery, the mRNA of collagen-I were 17.9±5.8, 7.2±1.8 and 6.7±2.4, the mRNA of collagen-Ⅱwere 12.5±3.4, 2.8±1.3 and 1.2±0.4 in SO, AGR and PGR group respectively. The SO group had significantly upregulation of collagen-I and collagen-II mRNA compared with the AGR and PGR groups at 3 days and 7 days respectively after surgery （P〈0.05） . There was a significant difference of the collagen-II between AGR group （2.8±1.3） and PGR group （1.2±0.4） at 7 days after injury （P〈0.05） . The fracture bony callus in PGR group was a significantly larger and less ossified than that in the AGR group. The mechanical load of fracture in SO group was larger than that of the other 2 groups （P〈0.05） .ConclusionSensory denervation negatively affects fracture-healing. The ganglion of sensory nerve plays an important role in bone fracture healing and normal innervation is essential for the fracture repair.