神经生长因子对胫骨骨折大鼠骨力学、骨强度及骨桥蛋白及下游相关因子水平的影响

Effects of nerve growth factor on bone mechanics,bone strength,osteopontin and levels of downstream related factors in the tibial fracture rats

目的 探讨神经生长因子(NGF)对胫骨骨折大鼠骨力学、骨强度及骨桥蛋白(OPN)及下游相关因子水平的影响。方法 将42只大鼠按照随机数字表法分为A组(腓肠肌两侧注射生理盐水)、B组(腓肠肌两侧注射NGF),每组21只。建立胫骨骨折模型后,观察两组骨痂的大小、骨折愈合情况,测定生物力学检测指标(最大载荷、弹性载荷、最大挠度)、胫骨骨强度指标(骨密度和骨矿含量),HE染色观察胫骨骨折形态,Western blot法检测OPN和局部黏着斑激酶(FAK)蛋白表达。结果 (1) B组骨折愈合更快,更早地完成了骨痂重塑,且愈合过程中,形成的骨痂更大。(2)术后1、3、5周,B组最大载荷、弹性载荷、最大挠度及OPN、FAK蛋白表达、骨密度明显大于A组(P<0.05),骨矿含量明显少于A组(P<0.05);A组术后各时间点各项指标比较差异均无统计学意义(P> 0.05);B组骨矿含量随时间推移逐步降低,其余指标随时间推移逐步升高(P<0.05)。(3) B组骨痂组织中软骨组织形成更早,面积更大,软骨组织向骨组织转化的过程更快。结论 NGF可以改善大鼠胫骨骨折最大载荷、弹性载荷、最大挠度,提高OPN的表达水平,促进胫骨骨折愈合。

Objective To investigate the influence of nerve growth factor(NGF) on bone mechanics, bone strength,osteopontin(OPN) and the levels of its downstream related factors in rats with tibial fractures.Methods The 42 rats were randomly divided into group A(injected normal saline into bilateral gastrocnemius) and group B(injected NGF into bilateral gastrocnemius),with 21 rats in each group. After the tibial fracture model was established,the size of callus and fracture healing of the two groups were observed;the follow data were determined,including biomechanical test indexes(maximum load,elastic load and maximum deflection),and tibial bone strength indexes such as bone mineral density(BMD) and bone mineral content(BMC);HE staining was used to observe the morphology of tibial fracture,and Western blot method was used to detect the expression levels of OPN and focal adhesion kinase(FAK)protein.Results(1) In group B,the process of fracture healing was faster,the callus remodeling was completed earlier,and the callus formed was larger in the process of healing.(2) At 1,3,5 weeks after operation,the maximum load,elastic load,maximum deflection,expression levels of OPN,FAK protein and BMD of group B were significantly superior to group A(P< 0. 05),while BMC of group B was significantly lower than that of group A(P< 0. 05);the various indexes of group A had no statistical differences at each time point(P> 0. 05). In group B,the BMC was gradually decreased with the passage of time,and the other indexes were gradually increased with the passage of time(P< 0. 05).(3) In group B,the formation time of cartilage tissue in the callus tissue was earlier,the area was larger,and the transformation process from cartilage tissue to bone tissue was faster.Conclusions NGF can improve the maximum load,elastic load and maximum deflection of tibial fracture in rats,which can improve the expression levels of OPN,and promote the healing of tibial fracture.