不同降解率β-TCP/rhBMP-2人工骨修复节段性骨缺损

Healing of segmental bone defects by β-TCP/rhBMP-2 composites with different degradation rate

目的检测不同降解率βTCP/rhBMP2复合人工骨修复节段性骨缺损的能力,探讨成骨与βTCP体内降解的关系。方法以不同工艺制备出三种不同降解率的βTCPβTCP1～3βTCP1、βTCP2分别与rhBMP2复合制备生成不同降解率的βTCP1/rhBMP2和βTCP2/rhBMP2复合人工骨。选择81只中国家兔,制成15mm长的双侧桡骨节段性缺损动物模型,分别用βTCP1/rhBMP2、βTCP2/rhBMP2、βTCP1、βTCP2、βTCP3修复桡骨缺损区。于术后第4、8、16和24周取材进行X线检查、组织学观察、计算机图像分析、生物力学测定、无机质含量测定和能量弥散X线分析。结果经X线检查和组织学观察发现,各实验组骨缺损部位均有新骨生成,成骨量随着时间的推移而增加。βTCP1/rhBMP2和βTCP2/rhBMP2两组的成骨数量和成骨速度均高于单纯βTCP组,其中以βTCP1/rhBMP2组成骨能力最强,术后24周时骨缺损已完全修复,骨髓腔出现;移植物的无机质含量、钙磷比值和生物力学性能均接近正常骨。复合人工骨移植材料与单纯βTCP相比,降解速度更快,24周时βTCP1/rhBMP2和βTCP2/rhBMP2两组的降解率分别为97.4%和73.4%。空白对照组在24周时骨缺损由纤维组织充填。结论不同降解率βTCP/rhBMP2人工骨具有修?

Objective To examine the segmental bone defects healing by β TCP/rhBMP 2 composites with different degradation rate and discuss the relationship between osteogenesis and degradation of β TCP in vivo. Methods Three kinds of β tricalcium phosphate(β TCP) with different degradation rate (β TCP1-3) were prepared by means of different techniques. β TCP/rhBMP 2 composites with different degradation rate(β TCP1/rhBMP 2 and β TCP2/rhBMP 2)were obtained by combining β TCP1, β TCP2 with recombinant human bone morphogenetic protein 2(rhBMP 2), respectively. β TCP1/rhBMP 2, β TCP2/rhBMP 2, β TCP1, β TCP2 and β TCP3 were used to repair 15 mm radial segmental defects in 81 Chinese rabbits. When the samples were harvested in 4, 8, 16 and 24 weeks after surgery, a series of examination were carried out, including the roentgenographical, histomorphological, biomechanical and computerized graphical analysis, energy dispersion analysis X ray (EDAX), and measurements of inorganic contents. Results Roentgenographically and histologically, all of the defects that had been treated with implants exhibited new bone formation, increasing with time. The quantity and rate of new bone formation in β TCP1/rhBMP 2 group and β TCP2/rhBMP 2 group were higher than those in group of β TCP alone. The ability of new bone formation in β TCP1/rhBMP 2 group was strongest. At 24 weeks the defects in β TCP1/rhBMP 2 group were bridged with the appearance of marrow cavities, the inorganic contents and ratio of calcium to phosphate and biomechanical property in implants approached to those of normal bone. Although degradation occurred to some extent in β TCP alone the degradation were faster in β TCP/rhBMP 2 composites. At 24 weeks the degradation rate in β TCP1/rhBMP 2 group and β TCP2/rhBMP 2 group were 97.4%and 73.4%, respectively. The defects in blank controls were repaired only by fibrous tissue at 24 weeks. Conclusion β TCP/rhBMP 2 composites with different degradation rate could repair segmental bone defects, and osteogenesis could accelerate the degradation of β TCP in vivo.