Objective To study the effects of neural epidermal growth factor like 1 (NELL-1) on healing of long bone fracture in Sprague-Dawley (SD) rats and observe the callus formation during bone healing period.Methods Mid radius fracture models were established in SD rats.NELL-1/bone morphogenetic protein 2 (BMP-2)-β-tricalcium phosphate (β-TCP) compound was constructed and implanted into the fracture zone.X-ray films were taken at 1st,2nd,3rd,and 4th week after surgery.The bone healing and callus formation were quantitatively analyzed.The t test was used to analyze the differences of bone haling scores and callus formation scores between NELL-1 and BMP-2.Variance analysis was used to evaluate trends of callus formation during bone healing period.Results NELL-1 can perform excellent bone healing ability equal to BMP-2 in mid radius fracture rats model,differences are not significant (P ＞0.05),Both group had over 50％ Bone healing score reached 4 by the end of the 4th week.In first 2-3 weeks,difference of callus formation between NELL-1 and BMP-2 group are of none significance,at an average score 2.5.During late period of bone healing procedure (3-4 weeks),callus of NELL-1 group achieve an average score 1.5,significantly smaller than group using BMP-2 (P ＜ 0.05).Conclusion NELL-1 is a promising bone healing and bone grafting protein that can be carried by β-TCP.As compared with BMP-2,NELL-1 can perform competitive bone healing ability with less callus formation.%目的 观察神经源性表皮生长因子样分子-1(NELL-1)促进大鼠长骨骨折愈合能力,评估骨折愈合过程中断端骨痂形成.方法 制作Sprague-Dawley大鼠桡骨中段骨折动物模型,在骨折断端位置植入含NELL-1/骨形态发生蛋白-2(BMP-2)的β-磷酸钙复合物,术后1、2、3、4周分别行手术部位X线摄片,对骨折愈合和骨痂形成量化分析.t检验比较NELL-1和BMP-2促进骨折愈合评分和骨痂形成评分;方差分析法比较实验组和对照组在不同时间段骨折愈合趋势及骨痂形成趋势.结果 NELL-1和BMP-2都能够很好地促进大鼠桡骨中段骨折愈合,第4周骨折愈合评分达4分者均超过50％,NELL-1和BMP-2促进哺乳动物长骨干部骨折愈合的能力差异无统计学意义(P＞0.05);骨折愈合2～3周时,NELL-1组骨痂形成评分均值为2.5分,与BMP组比较差异无统计学意义(P＞0.05),在骨折愈合后期(3～4周),NELL-1组形成骨痂评分均值均＜1.5分,低于于BMP-2组均值(P＜0.05).结论 NELL-1是一种具有可靠促进骨折愈合和新骨生成能力的生物活性蛋白,它在形成较小骨痂的情况下,能发挥与BMP-2相当的促进骨折愈合的能力.
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