异黄酮介孔玻璃水泥支架材料修复兔股骨骨缺损

Experimental research of isoflavone-loaded mesoporous glass cement scaffold materials for rabbit-femoral bone defect repair

目的评价异黄酮介孔玻璃水泥支架材料修复兔股骨骨缺损的效果。方法采用不同组分的骨水泥材料,并用介孔玻璃水泥粉末吸附植物性激素大豆异黄酮(isoflavone,IS),制备成载IS的硫酸钙(calcium sulphate,CS)骨水泥(CS/IS)、载IS的20%介孔硅酸钙镁/硫酸钙(20%mesoporous magnesium calcium silicate/calcium sulfate,20m-MCS/CS)骨水泥(20m-MCS/CS/IS)、载IS的40%介孔硅酸钙镁/硫酸钙(40m-MCS/CS)骨水泥(40m-MCS/CS/IS),检测不同骨水泥支架材料的体外释药性能。将60只成年雄性新西兰大白兔随机分成4组,每组15只,制作右侧股骨末端骨缺损模型后,分别植入CS、20m-MCS/CS、40m-MCS/CS以及40m-MCS/CS/IS,于术后第4、8、12周各组随机处死5只兔并取材,进行micro-CT扫描,脱钙后切片并进行三色染色,普通显微镜下观察。结果 20m-MCS/CS/IS和40m-MCS/CS/IS骨水泥对IS的释放均为缓释,但40m-MCS/CS/IS的释放量更多,在第25天已高达(41.0±1.8)%,因此后续实验中采用40m-MCS/CS/IS。动物实验表明,骨水泥支架植入12周后,CS组的缺损部位仍比较明显,20m-MCS/CS组有了一定程度的修复,40m-MCS/CS组已基本愈合,而40m-MCS/CS/IS组已基本完全愈合并且骨小梁已贯穿骨缺损区。三色染色结果显示40m-MCS/CS/IS复合骨水泥有更快的降解速度,能够促进大量新生骨和成熟骨的产生,其促成骨能力也优于40m-MCS/CS。结论异黄酮介孔玻璃水泥能有效修复腔隙性骨缺损,有望成为新型骨缺损修复材料。

Objective To evaluate the efficacy of isoflavone （IS）-loaded mesoporous glass cement scaffold materials in repairing the rabbit femoral bone defect. Methods Various composite glass cements absorbing plant hormones （soy isoflavone） were fabricated as follows： calcium sulphate （CS）, 20% mesoporous magnesium calcium silicate/calcium sulfate （20 m-MCS/ CS）, and 40% mesoporous magnesium calcium silicate/calcium sulfate （40 m-MCS/CS）. The in vitro isoflavone release profiles of the above materials were evaluated. Sixty New Zealand rabbits were randomized into 4 groups with 15 in each group, and the bone defect models in the distal end of femur were created. Group A： implanted with CS; Group B.. 20 m MCS/CS; Group C： 40 m-MCS/CS; and Group D.. IS-loaded 40 m-MCS/CS （40 m-MCS/CS/IS）. The rabbits were sacrificed at 4 weeks, 8 weeks and 12 weeks postoperatively and the bone samples were scanned with micro-CT. Then histology analysis was conducted under microscope after decalcification and Masson trichrome staining. Results Controlled release profiles of isoflavone were presented in both 20 m-MCS/CS/IS and 40 m-MCS/CS/IS groups, and a higher cumulative release rate was detected in 40 m-MCS/CS/IS group, which reached （41.0±1.8）% on the 25th day; therefore 40 m-MCS/CS/IS was selected for further evaluation in vivo, and 40 m-MCS/CS, 20 m-MCS/CS and CS served as controls. Rabbits in Group A implanted with CS showed little new bone formation 12 weeks after operation; those in Group B implanted with 20 m MCS/CS presented with better bone regeneration in the defect site; and the bone defect sites in group C grafted with 40 m-MCS/CS were almost filled with neo-bone; however, the best results were obtained in group D which was implanted with 40 m-MCS/CS/IS, with the defects fully repaired by the bone trabecular. Conclusion Isoflavone-loaded mesoporous glass cement can effectively repair lacunar bone defects, and may serve as a promising new bone regeneration material.