基因活化纳米骨浆异位诱导成骨能力的实验观察

Experimental investigations of the effect of the gene activated nanobone putty in inducing ectopic bone formation

目的观察纳米骨浆经成骨基因-人骨形态发生蛋白2（human bone morphogenetic protein 2，hBMP2）活化后是否具有异位诱导成骨能力。方法昆明种小鼠24只，4周龄，体重（20±2）g，随机分为两组。两组小鼠右侧大腿后群肌袋均注射纳米骨浆＋hBMP2质粒，作为实验侧；1组：左侧大腿后群肌袋注射纳米骨浆＋空白质粒，作为对照侧1；2组：左侧大腿后群肌袋注射纳米骨浆，作为对照侧2。术后2、4周，采用放射学、分子生物学和组织形态学等方法检测成骨基因hBMP2表达和诱导成骨效应。结果术后所有动物均存活，饮食活动正常。RT-PCR和Western blot检测发现术后2、4周实验侧注射材料组织有hBMP2表达。术后2周，实验侧植入材料出现大量软骨组织和呈岛状散在分布的骨组织，对照侧未见骨组织形成。术后4周，实验侧可见大量骨化组织，新生骨相互融合生长并形成较为成熟的板层骨和骨小梁结构；对照侧植入材料外周有较多纤维结缔组织，未见骨或软骨形成。术后2、4周，实验侧碱性磷酸酶活性均明显高于对照侧（P〈0．01），差异有统计学意义。结论纳米骨浆在hBMP2基因质粒活化后具有显著的骨诱导活性。

Objective To investigate the osteogenic potential of the human bone morphogenetic protein 2 0（hBMP2） gene activated nanobone putty. Methods Twenty-four Kunming mice {four weeks age with the mean weight of （20±2） g] were used in this experiment. The mice were divided into two groups randomly. The nanobone putty＋hBMP2 plasmid was injected into the right thigh muscle pouches of all mice （experiment side）. The nanobone putty＋blank plasmid or nanobone putty was injected into the left thigh muscle pouches of the group 1 （control side 1） or group 2 （control side 2） respectively. The effect of eetopie bone formation was evaluated by radiography, histology, molecular biology analysis in 2 and 4 weeks after operation. Results All the animals survived and recovered well from the operation. The tissues of the experiment side had the expression of hBMP2 detected by RT-PCR and Western blot at 2, 4 weeks after operation. Two weeks after operation, obviously cartilage and small island immature bone formation in implants of the experiment side were observed and no bone formation was observed in the control side. Four weeks after the operation, large amount of bone tissue was observed in the experiment side and the neogenetie bone integrated mutually to form matured woven bone and bone trabeeula; there was much fibrous connective tissue around embedded materials in control side of the mice but no bone or cartilage formation observed. The alkaline phosphatase activity in the experiment side was obviously higher than that in the control side （P〈 0.01 ）. Conclusion The gene activated nanobone putty has a obviously activity in inducing eetopie bone formation.