脑和脊髓损伤对骨折股骨骨痂中NGF表达影响

目的 研究大鼠脑和脊髓损伤后骨折股骨骨痂中神经生长因子（NGF）表达的变化。方法 成年健康雌性Wistar大鼠48只，随机分为单纯股骨骨折组、股骨骨折并脑损伤组和股骨骨折并脊髓损伤组，每组16只，每组再分为骨折后1、4、7、14d观察组。应用自由坠落重物撞击法建立脑和脊髓损伤动物模型，免疫组织化学方法检测各组骨痂中NGF的表达。结果 单纯骨折组表现为典型的骨折愈合过程，骨痂内纤维母细胞及成骨细胞内NGF阳性表达相对较弱。骨折并脑损伤组早期纤维性骨痂形成较慢，骨折早期骨痂内成纤维细胞及成骨细胞NGF表达较弱，第14天表达增强，出现成骨细胞。骨折并脊髓损伤组早期形成大量纤维骨痂和软骨骨痂，NGF强阳性表达，第14天已有编织骨形成，NGF表达达高峰。结论 并发脊髓损伤的股骨骨折愈合较快，NGF表达明显增强，提示NGF可能具有促进骨折愈合的作用。

EFFECT OF CEREBRAL AND SPINAL CORD INJURY ON EXPRESSION OF NERVE GROWTH FACTOR IN BONY CALLUS OF FRACTURED THIGHBONE

Objective To study the expressive change of nerve growth factor(NGF) in bony callus after fracture of the thighbone in rats with cerebral and spinal cord injury. Methods Forty-eight adult healthy female Wistar rats were randomly divided into thighbone-fracture group(n=16),thighbone-fracture-with-cerebral-injury group(n=16) and thighbone-fracture-with-spinal-cord-injury group(n=16).Each group was further divided into post-fracture(one-day,four-day,seven-day and 14-day) subgroups,with four rats in each subgroup.The animal models were established by free weight dropping and knocking method,expressions of NGF in bony callus were determined by immunohistochemical assay. Results The animal models in simple fracture group appeared a typical healing course,NGF expressed weakly in fibroblast and chondroblasts in callus.In fracture with cerebral injury group,the callus formed slowly and NGF expressed weakly at early stage of fracture,but increased and appeared chondroblasts at 14 days.In fracture with spinal cord injury group,there was a quantity of fibrous callus and cartilaginous callus formation and NGF positive expression at early stage,and bone formation with NGF highest expression at 14 days. Conclusion The thighbone fracture recovers rapidly and NGF in the callus expresses highly in fracture-with spinal-cord-injury group,which suggests that NGF could yield the healing of the fracture.