骨形成蛋白和转化生长因子-β对兔尺骨骨折愈合后生物力学性能的影响

EFFECTS OF BONE MORPHOGENETIC PROTEIN AND TRANSFORMING GROWTH FRACTOR-β ON BIOMECHANICAL PROPERTY FOR FRACTURE HEALING IN RABBIT ULNA

目的 探讨外源性骨形成蛋白 (BMP)和转化生长因子 -β(TGF-β)对骨折愈合后生物力学性能的影响。 方法 36只日本大耳白兔 ,体重 3.5～ 4 .5 kg。随机分成 4组 :空白对照组、TGF-β组、BMP组和 TGF-β+BMP组 ,每组 9只。采用兔尺骨骨折模型 ,在骨折局部将聚乳酸 (PAL )为载体制备成 TGF-β/ PAL、BMP/ PAL、TGF-β+BMP/PL A缓释系统 ,手术当天将各缓释系统植入骨折区 ,对照组在相应部位置入 PAL ,术后 5 0天取材 ,通过三点弯曲法测骨折愈合后整体骨弯曲结构力学性能的变化。取断端密质骨 ,用三点弯曲、压缩和拉伸方法测骨试件的材料力学特性的变化 ,同时测骨痂的几何参数和骨密度的变化来对骨折愈合进行评估。 结果 治疗组尺骨的几何参数 ,整体骨弯曲的破坏载荷、极限强度和弹性模量 ,骨试件的弯曲、压缩和拉伸的极限强度 ,以及弯曲和压缩的弹性模量明显高于对照组 ,各治疗组与对照组比较 ,具有统计学意义 (P<0 .0 1) ,TGF-β+BMP组高于 TGF-β和 BMP组 ;TGF-β组高于 BMP组 ,各治疗组之间两两比较 ,有统计学意义 (P<0 .0 5 )。在骨密度方面 ,各治疗组与对照组之间无明显差异。 结论 兔骨折周围局部应用外源性 TGF-β和 BMP可促进骨痂形成 ,增强骨折愈合后骨组织的生物力学强度 ,TGF-β的作用优?

Objective To investigate the effects of exogenous bone morphogenetic protein(BMP) and transforming growth factor-β(TGF-β) on biomechanical property for ulna of fracture healing.Methods Thirty-six adult rabbits were made the model of right ulnar fracture and treated locally with TGF-β/PLA, BMP/PLA,TGF-β+BMP/PLA or PLA(as control group). Fracture healing was evaluated by measurement of the mechanical parameters and geometric parameters.Results As compared with control group, the geometric parameters, the bending broken load, the ultimate bending strength, the bending elastic modulus, the ultimate flexural strength, the flexural elastic modulus, the ultimate compressing strength, the compressing elastic modulus, and the ultimate tensile strength for ulna of fracture healing increased significantly in the treatment groups( P< 0.01). These parameters were higher in TGF-β+BMP/PLA group than in TGF-β/PLA group or in BMP/PLA group and in TGF-β/PLA group than in BMP/PLA group( P< 0 05). There was no significant difference in bone density between the treatment groups and control group. Conclusion Local application of exogenous TGF-β and BMP can increase the callus formation and enhance biomechanical strength of bone after fracture healing. A combination of TGF-β and BMP has synergetic effect in enhancing fracture healing.