神经生长因子对失神经状态下大鼠骨折愈合的影响

Effect of nerve growth factor on denervated bone fracture healing in rats

目的:探讨神经生长因子(NGF)对脊髓完全横断伴胫骨骨折大鼠骨折愈合的影响。方法:120只SD大鼠随机分成3组:胫骨骨折组(F组,n=40),T_(10)脊髓完全性损伤合并胫骨骨折组(FS组,n=40),T_(10)脊髓完全性损伤合并胫骨骨折应用神经生长因子治疗组(FSN组,n=40)。FS组及FSN组大鼠建立T_(10)脊髓完全横断伴胫骨骨折模型,F组制备单纯胫骨骨折,伤后第4周对3组大鼠骨折断端行断层CT扫描,测量骨折断端最大横截面并计算骨痂灰度值;行生物力学三点弯曲试验;行骨组织形态计量学检查;骨密度测定;骨痂组织形态学观察;免疫组化法测定骨痂组织中骨钙素(OCN)的表达;观察3组大鼠骨痂中成骨细胞的超微结构变化;Western印迹检测Ⅰ、Ⅱ型胶原的表达。结果:F组骨痂断面最大直径明显小于FS组(P<0.01)和FSN组(P<0.05),FSN组小于FS组(P<0.05);骨痂灰度值结果类似。三点折弯试验、骨计量学观察均发现F组各项生物力学参数优于其他2组(P<0.05);FSN组优于FS组(P<0.05)。F组大鼠胫骨骨痂中OCN及Ⅰ型胶原蛋白表达明显高于其他2组(P<0.05),FSN组高于FS组(P<0.05);而F组骨痂Ⅱ型胶原蛋白的表达明显低于FS组及FSN(P<0.05),FSN组亦高于FS组(P<0.05)。形态学及超微结构观察见F组骨折愈合最佳,FSN组优于FS组。结论:失神经营养会影响骨折断端的骨化;神经生长因子对失神经状态下骨折断端的骨化有促进作用。

Objective：To study the effect of nerve growth factor （NGF） on bone fracture healing of inflicted T10, spinal cord injury （SCI） complicated with tibia fracture in rats. Methods： Totally 120 rats were randomly divided into tibia fracture group （Fgroup, n=40）, T10 SCI ＋ tibia fracture group （FS group, n=40）, and T10 SCI ＋ tibia fracture ＋ NGF group （FSN group, n=40） . Four weeks later, the fracture sites in the 3 groups were subjected to CT scanning; the maximum transverse diameter of the fracture ends and the gray scales of non osseous area were measured; the changes of biomechanics property of the fracture ends were determined by three-point bending test; the bone morphometry, bone density, and histomorphology of callus were determined; the expression of （）CN was detected by immunohistochemical method; the osteoblast ultrastructure was observed by TEM and the expression of Ⅰ , Ⅱtype collagen were examined by Western blotting. Results： The maximum transverse diameter of F group was less than those of FS group（P〈0.01）and FSN group （P〈0.05）, and FS group was longer than FSN group（P〈0.05） ; the comparison of gray scales among 3 groups had a similar result to that of the section diameter. Three points bending test and bone morphometry test showed that the biomechanics property of the fracture ends in F group were better than thoseof the other 2 groups （P〈0.05）, and FSN group was better than FSgroup （P〈0.05）. The expression of OCN and type i collagen in the callus of F group was significantly higher than that of the other 2 groups （P〈0.05）, and FSN group was higher than FS group （P〈0.05）; while lhe expression of type Ⅱ collagen in F group was lower than that of the other 2 groups（P〈0.05）, and FSN group was higher than FSgourp （P〈0.05）. Morphological and uhrastructureobservation showed that fracture in F group had the best healing result, and the healing result of FSN group was better than that of the FS group. Conclusion： It is suggested that denervation can affect the ossification of fracture ends and NGF can promote the ossification of fracture ends suffering denervation.