中枢神经系统损伤和股骨骨折愈合的关系

目的观察大鼠脑和脊髓损伤后骨折股骨骨痂中神经生长因子（NGF）的受体TrKA表达的变化，以探讨中枢神经系统损伤对骨折愈合的影响和机理。方法选择成年健康雄性Wistar大鼠48只，随机分为单纯股骨骨折组（对照组）16只；股骨骨折合并脑损伤组（实验组A）16只：股骨骨折合并脊髓损伤组（实验组B）16只。每组再分为骨折后1天、4天、7天和14天4个观察骨折愈合时间点，每个观察时间点4只。应用自由坠落重物撞击法建立脑和脊髓损伤的动物模型，以免疫组织化学方法检测各骨折愈合时间点骨痂中NGF受体TrKA的表达变化。结果单纯骨折组骨痂内的纤维母细胞和成骨细胞内NGF受体TrKA呈阳性表达；骨折合并脑损伤组，骨折后1天、4天和7天骨痂内成纤维细胞和成骨细胞内的NGF受体TrKA的阳性表达率与单纯骨折组比较无差异性，至骨折后第14天表达增强（P〈0．05）；骨折合并脊髓损伤组，至骨折后第4天开始明显增多（P〈0．05），7-14天达高峰（P〈0．01）。结论合并脑损伤与合并脊髓损伤时股骨骨折愈合速度增快，这可能与骨折部位骨痂中NGF受体Trk的表达上调有关。

The relation of central nerve system injury and femoral fracture heal

Objective: To observe expression changes of Nerve Growth Factor(NCF) receptor TrKA in callus of femoral fracture after brain and spinal cord injury in rats,and to investigate the influence and mechanism of central nervous system injury on fracture healing.Methods: A total of 48 healthy female adult Wistar rats were selected and randomly assigned to three groups: 16 with simple femoral fracture(control group),16 with femoral fracture combined with brain injury(intervention group A) and 16 with femoral fracture combined spinal cord injury(intervention group B).Each group was divided into four smaller groups and observed on 1st day,4th day,7th day and 14th day after fracture.The animal model was set up by free fall weight drop.NCF and its receptor TrKA expression changes in callus tissue were tested at each fracture healing time point by immunohistochemical method.Results: According to immunohistochemical test results,NCF receptor TrKA in fibroblast and osteoblast of callus in the control group was positively expressed.There was no difference in positive expression rate of NCF receptor TrKA in fibroblast and osteoblast of callus on 1st day,4th day and 7th day between intervention group A and control group.The expression of NCF receptor TrKA increased on 14th day(P<0.05).For intervention group B,the expression of NCF receptor TrKA began to increase significantly on 4th day(P<0.05) and reached a peak from 7th day to 14th day(P<0.01).Conclusion: Femoral fracture heals faster when combined with brain and spinal cord injury.It may be associated with the expression up-regulation of NCF receptor TrKA in callus of fracture sites.