目的 将改性的壳聚糖包裹骨形态发生蛋白4(BMP4)质粒形成核壳结构,以明胶海绵为此纳米粒子载体,探究其对兔桡骨临界骨缺损的修复作用.方法 新西兰大白兔24只,每只兔子的左右前肢按随机法分为负载BMP4质粒核壳结构组(TACS@EG-HBC/pBMP4/G组)、负载BMP4质粒核结构组(TACS/pBMP4/G组)和对照组.在双侧桡骨制备长约18 mm的完全性临界骨缺损,分别植入含有TACS@EG-HBC/pBMP4或TACS/pBMP4的明胶海绵,对照组仅植入单纯的明胶海绵.术后2、4、8、12周取标本做分别处理,检测缺损部位的大体标本、骨密度及骨矿物质含量、X线、HE染色、免疫组化法、生物力学.结果 24只兔子均纳入分析,术后切口未见感染、化脓等症状.大体标本示:TACS@EG-HBC/pBMP4/G组骨缺损完全骨化修复;骨密度及骨矿物质含量显著高于TACS/pBMP4/G组和对照组(P＜0.05);X线示:术后12周骨缺损处已完全修复,骨髓腔已再通;HE染色结果显示:新生骨小梁相互连接成板层骨;免疫组化结果显示:BMP4棕色蛋白染色明显;生物力学测定结果显示:所形成的新生骨与正常骨组织生物力学差异无统计学意义.结论 TACS@EG-HBC/pBMP4/G具有良好的安全性和成骨能力.%Objective To evaluate the core-shell nanoparticles ecapsulated with bone morphogenetic protein 4 plasmids ability of bone regeneration in a critical sized radius defect.Methods 24 New Zealand white rabbits were randomly divided into two group:experimental groups and control group.Prepared 18 mm complete bone defect model at the bilateral radius,the experimental groups were implanted with TACS@EG-HBC/pBMP4/G and TACS/ pBMP4/G,While control groups implanted with only gelatin sponge.The radius bone defect were observed by bone mineral density and bone mineral content,anatomy,X ray,HE staining,immunohistochemistry and biomechanical testing at 2,4,8,12 weeks.Results All the 24 rabbits were in analysis and no injection and diapyesis was foundaround the incision.At 12 weeks after operation,new bone formation significantly increased in the TACS@EG-HBC/pBMP4/G treatment.It demonstrated significant increase in BMC and BMD values (P ＜ 0.05) compared to the other two groups at 2,4,8 and 12 weeks.X-ray also showed the reunion of bone marrow cavity at 12 weeks.HE staining:new bone trabecula interconnected turnedinto lamellar bone.Immunohistochemistry:protein BMP4staining with brown color was apparent.It also showed the bending stiffness of regenerated new bones at 12 weeks have no statistical differences compared with the normal radius.Conclusion TACS@EG-HBC/pBMP4/G is biosecurity and can be used to repair bone defect.
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