纳米羟基磷灰石/聚酰胺复合材料的人工肱骨头体内成骨中BMP-2及其基因表达研究

目的：对新型纳米晶骨修复和前建复合材料（n-HA／PA66）人工肱骨头的成骨能力及将其作为人工关节替代品的可行性进行评价。方法：新西兰大白兔20只，行双侧肱骨头切除，以nHA／PA人工肱骨头进行双侧肱骨头置换术。术后1、2、3、4、6、12、24周处死周分别处死动物。对假体与受体骨界面先行大体观察，然后分别用甲基丙烯酸甲酯（PMMA）制作硬组织片，甲苯胺兰染色和Masson染色后，对n-HA／PA人工肱骨头与受体骨界面进行BMP-2免疫组织化学检测和原位杂交BMP-2基因表达检测。结果：人工肱骨头在动物体内成骨的BMP-2及其基因表达研究显示，假体植入第3周，免疫组织化学染色显示BMP-2即有弱阳性表达，至6，12周为强阳性；第24周，BMP表达阳性率及阳性程度均有所降低。此外，原位杂交观察假体植入第1、2周，成骨细胞中BMP-2 mRNA表达呈弱阳性，第3周成骨细胞中BMP-2 mRNA表达呈强阳性，而在第4周，成骨细胞中表达阳性率和阳性程度均有所下降。研究显示人工肱骨头体内成骨的BMP-2及其基因表达高峰时间较文献报道的骨折模型晚。结论：n-HA／PA66人工肱骨头具有良好的成骨能力，作为新型人工关节材料为可与受体骨发生生物键合。

Study of BMP-2 and BMP-2 gene expression in the osteogensis in the interface of the n-HA/PA composite implant

Objective:To evaluate the ability osteogenesis of the nano-hydroapatite crystals and polyamide composite(n-HA/PA66),and the feasibility use it as substitute material of artifical joint, Methods:The animal models of bilaterial humeral head replacement with surgery in the twenty New Zealand white rabbits, and were implanted with n-HA/PA66 artifical humeral head . The effect were observed by gross and histopathlogical examnation at 1,2,3,4,6,12,24W after operation .In the mean time, Bone morphogenetic protein-2 (BMP-2) on the interface beteen the n-HA/PA composite and the receptor bone was examined by immunohistochemistry staining , and the BMP-2 gene expression on this interface was examined by use of in situ hybridization. Results:The the expression of BMP-2 was weak positive in the interface membranes at 3rd week. At 6th week and 12th week, the BMP-2 expression was strong positive,One week and two weeks after operation, BMP-2 mRNA expressions in osteoblasts were weak. Three weeks after operation, BMP-2 mRNA expression was highest. This investigation indicated that the expression of BMP-2 and BMP-2 gene in the interface was later than that in fracture healing reported in other papers. Conclusion:Our results show n-HA/PA66 have good ability of osteogenesis , indicates it can be used as the substitute material of artifical joint.