BMP-2修饰掺锶磷酸钙修复去卵巢大鼠股骨干骺端骨缺损实验研究

Experimental study on BMP-2 modified strontium-doped calcium phosphate in repairing bone defect of femoral epiphysis in ovariectomized rats

目的:探索骨形态发生蛋白2(BMP-2)修饰掺锶磷酸钙(CPC)修复去卵巢大鼠股骨干骺端骨缺损疗效及可能的机制。方法:3月龄雌性Sprague Dawley大鼠去卵巢术后12周后OVX组大鼠随机分为对照组(Con组)、CPC组(CPC组)、BMP-2/CPC组(BCPC组)和BMP-2/Sr/CPC组(BSCPC组),随后制作缺损模型并植入相应材料治疗。8周后取双侧股骨进行微型计算机断层扫描(Micro-CT)和组织学检测。同时蛋白印迹(Western blot)检测各组大鼠缺损部位Notch 1、CBF 1、Jagged 1和RUNX-2的蛋白表达改变。结果:Micro-CT和HE切片显示,与Con组相比,BSCPC组和BCPC组缺损部位较多的新形成骨组织充填,缺损区被修复较多,但是可见较多的生物材料残留。与CPC组或BCPC组相比,BSCPC组缺损部位从缺损边缘到中心均可见大量的骨组织形成,可见较多成熟骨组织,只有较少的生物材料残留。定量结果显示CPC组、BCPC组和BSCPC组微结构参数BV/TV、Tb.Th、Tb.N高于Con组,而Tb.Sp低于Con组(P<0.05)。Western blot检测结果显示与Con组比较,CPC组、BCPC组和BSCPC组Notch 1、CBF 1、Jagged 1和RUNX-2蛋白表达上调。结论:BMP-2修饰CPC能有效修复去卵巢大鼠股骨干骺端骨缺损,且可能通过Notch信号通路激活和RUNX-2表达上调来实现的。

Objective:To investigate the efficacy and potential mechanism of BMP-2 modified strontium-doped calcium phosphate in repairing bone defects of femoral epiphysis in ovariectomized(OVX)rats.Methods:Twelve female Sprague Dawley(SD)rats aged 3-month old and following OVX were randomly divided into group of OVX,control(Con group),calcium phosphate cement treatment(CPC group),BMP-2/CPC(BCPC group)and BMP-2/Sr/CPC(BSCPC group).Then the defect model was prepared and the corresponding materials were implanted to treat the defect.After 8 weeks,bilateral femurs were taken to undergo microcomputer tomography(Micro-CT)and histological examination.Western blot was performed to detect the protein expression of Notch 1,CBF 1,Jagged 1 and RUNX-2 in the defect region of rats in each group.Results:Micro-CT and HE sections indicated more newly formed tissues filling in the bone from the edge to the center of the detected region in rats in BSCPC group and BCPC,with much mature bone tissue yet less biomaterial residues compared to Con group.The quantitative results showed that the microstructural parameter BV/TV,Tb,Th,Tb And N were significantly higher,yet Tb and Sp were markedly lower in CPC group,BCPC and BSCPC group than in Con group(all P<0.05).Western blotting revealed up-regulated Notch 1,CBF 1,Jagged 1 and RUNX-2 expression in CPC,BCPC and BSCPC group compared to the Con group.Conclusion:BMP-2-modified strontium-doped calcium phosphate can effectively repair the bone defect of femoral epiphysis in ovariectomized rats.The potential mechanism is achieved through activation of Notch signal pathway and up-regulation of RUNX-2 expression.