骨形态发生蛋白-2基因活化纳米骨浆修复兔桡骨缺损的实验研究

Repairing radial defects by implanting BMP-2 gene activated nanobone putty in rabbits

目的观察骨形态发生蛋白-2（BMP-2）基因活化纳米骨浆在损伤部位的局部成骨基因表达和骨缺损重建修复效果。方法新西兰白兔54只，其中48只实验动物随机分成三组（每组16只32侧），制成双侧桡骨中段15mm骨缺损模型。A组：注入hBMP-2＋纳米骨浆；B组：注入空白质粒＋纳米骨浆；C组：注入纳米骨浆。另6只动物制作左桡骨中段骨缺损，不植入材料，作为空白对照。术后4、8和12周取材行影像学检查、组织学观察、分子生物学检测和生物力学检测。结果术后12周A、B和C组骨缺损均修复，A组骨缺损处有明显BMP-2的mRNA和蛋白质表达，在ALP水平、成骨速度、新生骨量及新生骨力学强度等方面均明显优于B、C两组（P〈0．05）。空白对照组骨缺损无愈合。结论纳米骨浆复合BMP-2质粒后，具有一定骨诱导作用，植入体内后成骨速度、质量及力学强度较单纯的纳米骨浆明显增强，能够有效修复骨缺损。

Objective To investigate the possibility of repairing bone defects with the BMP-2 gene activated nanobone putty. Methods Models of bilateral 15 mm radial defects were made in 48 rabbits and divided into equal 3 groups randomly. The defects were treated with different materials： in group A nanobone putty ＋ hBMP-2 plasmid were used; in group B nanobone putty ＋ blank plasmid were used; and in group C only nanobone putty was used. Models of left radial defects were made in other 6 rabbits as blank control. The effects of bone repairing were evaluated by radiographic, histological, molecular biological and biomechanic analyses at 4, 8 and 12 weeks after operation. Results All the animals recovered well from the operation. In group A, the new bone tissue at the defects showed obvious expression of BMP-2 protein and higher ALP level. The rate of new bone formation and anti-bending strength in group A were significantly higher than those in groups B and C. The defects in blank control were not healed. Conclusion As implants of BMP-2 gene activated nanobone putty can better induce bone formation, increase bone formation rate and bone anti-bending strength, they can be used to repair bone defects more effectively than implants of pure nanobone putty.