BMP-7基因促进大鼠下颌牵张成骨的研究

Bone regeneration accelerated by BMP-7 gene in rat mandibular distraction osteogenesis

目的:探讨骨形成蛋白-7(BMP-7)基因修饰的自体骨髓间充质干细胞(MSCs)促进大鼠下颌牵张骨痂形成的可行性。方法:选用48只雄性SD大鼠,随机分为实验和对照2组。建立大鼠下颌DO模型;于牵张结束最后1d,实验组大鼠牵张间隙内注射转染重组质粒pEGFP-BMP7的自体骨髓MSCs;而对照组大鼠注射转染pEGFP-N1空质粒的MSCs。分别于固定期第2、4、8周分3批处死大鼠,进行放射学、组织学观察,并进行骨组织形态计量学分析。结果:实验组牵张间隙内新骨形成和骨痂密度均明显高于对照组;计量学分析也显示各时间点实验组新生骨量(NBV1和NBV2)和新生骨小梁宽度(TNT)均显著高于对照组(P<0.01)。结论:基于MSCs的BMP-7exvivo基因治疗可有效促进DO新骨形成,从而缩短固定期,为临床颅颌面骨缺损的重建提供了一个极具价值的修复策略。

Objective： To study the effects of BMP-7 gene transfected bone marrow mesenchymal stem cells （MSCs） on callus acceleration in rat mandibular distraction osteogenesis. Methods. Forty-eight adult male SD rats were randomly divided into experimental and control groups. MSCs were obtained from individual rat and transfected by pEGF-P-BMP7 for the 24 experimental rats and by the empty vector pEGFP-N1 for the 24 control rats. The rats were underwent right mandibular distraction. 1 × 10^6/100μl BMP-7 gene transfected cells in 10μl of normal saline were injected into the distraction gap in each experimental rat, while the same number of empty vector transfected cells in each control rat, The distracted mandibles were harvested 2, 4, and 8 weeks respectively after cell injection and evaluated by radiological, histological and histomorphometric analysis. Results：Radiological and histological ex- aminations showed that more new bone was formed in experimental group than in control. Histomorphometric analy- sis also demonstrated that both new bone volume （NBV1 and NBV2） and the thickness of new trabeculae （TNT） were significantly higher in experimental rats than those in control（ P 〈 0. 01 ）. Conclusiion： BMP-7 gene can accelerate new bone formatinn in rat mandibular distraction osteogenesis.