骨不连接区成骨活性的实验研究

Osteogenesis activity in site of bone nonunion

目的检测骨不连骨断端骨形态发生蛋白（BMP）、核心蛋白多糖成分的表达，观察单独应用和联合应用两种因子治疗骨不连的效果。方法制作兔桡骨肥大型骨不连动物模型，通过大体观察、影像学和组织学检测，比较骨断端组织成分的变化。采用免疫组织化学染色、Real—timePCR、Western—Blot检测骨不连接区组织中BMP、核心蛋白多糖的表达。分别用单纯BMP（A组）、纤维蛋白胶复合BMP和核心蛋白多糖（B组）、单纯核心蛋白多糖（C组）和空白组溶解液（D组）局部注射骨不连接区，通过三维CT观察骨不连接区的成骨情况。结果组织学检测示骨折愈合侧组织内大量新生骨组织和新生血管形成，骨不连侧组织内主要为纤维瘢痕组织。免疫组织化学检测显示骨折愈合侧可见核心蛋白多糖染色和BMP染色阳性；骨不连接侧无明显核心蛋白多糖表达，BMP-2表达阴性。骨愈合侧和骨不连侧核心蛋白多糖的相对表达量分别为2．40±0．260、1．313±0．187，差异有统计学意义（t=10．193，P=0．000）。Western—Blot检测示骨不连接侧组织BMP-2的表达较骨折愈合侧明显下降（t=69．007，P=0．000）。A、B、C、D组局部注射治疗骨不连的成骨量CT值分别为551．40±41．85、674．40±36．55、471．40±27．91、309．20±147．86，差异有统计学意义（F=18．209，P=0．000）。结论骨不连形成后，由于BMP和核心蛋白多糖成分的减少，局部组织的抗纤维化能力和成骨能力下降，联合应用外源性BMP和核心蛋白多糖能促进骨不连接区陈旧性组织成骨。

Objective To investigate expressions of BMP and decorin at the broken ends of bone nonunion after fracture and effects of percutaneous injection of exogenous BMP and decorin, alone or in combination, on treatment of nonunion. Methods Radial nonunion models were made in rabbits. Changes in tissue components at broken ends of the fractured bone were observed through microscopy, radiology and histology. The expressions of BMP and decorin were detected by immunohistochemistry, real-time PCR and Western-Blot. Fibrin sealant （FS） was adopted for percutaneous injections of exogenous BMP and decorin, alone or in combination, into the bone nonunion sites. Ossification in the area of nonunion was observed by 3D CT 4 weeks after the injection. Results In areas of bone nonunion, the active cells that could differentiate into osteoblasts obviously diminished and the expressions of BMP and decorin, compared with those in the normal bone, decreased obviously（ P 〈 0. 05）. Injection of both BMP and decorin were more effective than injection of either of them alone in treatment of nonunion. Conclusions Becaus of an obvious decrease of BMP and decorin, local tissues in bone nonunion tend to show less anti-fibrosis and ossification abilities. Therefore, a combined injection of exogenous BMP and decorin can promote healing of the bone nonunion.