贻贝启发接枝骨形态发生蛋白2成骨活性肽的介孔生物玻璃修复股骨髁缺损

Repair of femoral condyle defects using mesoporous bioactive glass grafted with bone morphogenetic protein 2 osteogenic peptide inspired by mussel

背景:骨形态发生蛋白2在胚胎发育、骨骼形成和再生修复中具有重要作用,但高剂量应用与癌症发病密切相关。骨形态发生蛋白2成骨活性段L20能够有效减少癌症等不良反应,并可显著促进骨组织再生。目的:将骨形态发生蛋白2活性肽段以贻贝衍生肽模拟策略接枝在介孔生物玻璃表面,探究其对组织工程成骨性能的影响。方法:(1)采用模板法合成介孔生物玻璃纳米颗粒,采用一步法合成负载骨形态发生蛋白2成骨活性肽L20的介孔生物玻璃纳米颗粒,表征负载骨形态发生蛋白2成骨活性肽L20介孔活性玻璃纳米颗粒的形貌与体外缓释性能。(2)分离提取SD大鼠骨髓间充质干细胞,传2代后分别与PBS(空白组)、介孔生物玻璃纳米颗粒(对照组)、负载骨形态发生蛋白2成骨活性肽L20介孔生物玻璃纳米颗粒(实验组)共培养,采用细胞活死荧光染色和CCK-8法检测细胞毒性和细胞增殖,扫描电镜观察细胞黏附;成骨诱导分化后,进行碱性磷酸酶染色、茜素红S染色与成骨相关基因表达检测。(3)取15只SD大鼠,建立双侧股骨髁缺损模型,采用随机数字表法分为3组:空白组(n=5)不植入任何材料,对照组(n=5)植入介孔生物玻璃纳米颗粒,实验组(n=5)植入负载骨形态发生蛋白2成骨活性肽L20介孔生物玻璃纳米颗粒。术后8周,进行股骨Micro-CT扫描与组织形态观察。结果与结论:(1)扫描电镜下可见负载骨形态发生蛋白2成骨活性肽L20介孔生物玻璃纳米颗粒为球形、单分散颗粒,透射电镜下可见其具有多孔结构,平均粒径为(268.10±0.58) nm,体外可缓释L20。(2)负载骨形态发生蛋白2成骨活性肽L20介孔生物玻璃纳米颗粒无细胞毒性,并且可促进骨髓间充质干细胞的增殖与黏附;与空白组、对照组相比,实验组碱性磷酸酶活性与细胞外基质矿化能力均升高(P <0.05),碱性磷酸酶、Runx2、骨钙素mRNA表达升高(P <0.05)。(3)股骨Micro-CT扫描结果显示,与空白组、对照组相比,实验组新生骨量与骨密度均升高(P <0.05);苏木精-伊红与Masson染色结果显示,与空白组、对照组相比,实验组新骨生成与胶原纤维均增加。(4)结果表明,负载骨形态发生蛋白2活性肽L20介孔生物玻璃纳米颗粒具有良好的生物相容性及体内外促成骨性能,可促进SD大鼠股骨髁缺损的再生修复。

BACKGROUND:Bone morphogenetic protein 2 is vital in embryonic development,bone formation,and regeneration,but its high-dose application is linked to cancer.Bone morphogenetic protein 2 osteogenic peptide L20 reduces adverse effects like cancer and boosts bone tissue regeneration.OBJECTIVE:To graft bone morphogenetic protein 2 active peptide segments onto mesopores and surfaces through a peptide mimicry strategy inspired by oysters,and explore its impact on osteogenic properties of tissue-engineered bone.METHODS:(1)Mesoporous bioactive glass was synthesized using a template method.Bone morphogenetic protein 2 osteogenic peptide L20 was loaded onto mesoporous bioactive glass using a one-step synthesis method to characterize the morphology and in vitro sustained release properties of mesoporous active glass nanoparticles loaded with bone morphogenetic protein 2 osteogenic active peptide L20.(2)Bone marrow mesenchymal stem cells were isolated and extracted from SD rats.After two generations,they were co-cultured with PBS(blank group),mesoporous bioactive glass nanoparticles(control group),and mesoporous bioactive glass nanoparticles loaded with bone morphogenetic protein 2 osteogenic active peptide L20(experimental group).Cell live/dead fluorescence staining and CCK-8 assay were used to detect cytotoxicity and cell proliferation.Scanning electron microscopy was used to observe cell adhesion.After osteogenic induction and differentiation,alkaline phosphatase staining,Alizarin red S staining,and osteogenesis-related gene expression were detected.(3)Fifteen SD rats were selected to establish bilateral femoral condyle defect models and divided into three groups using a random number table method:the blank group(n=5)was not implanted with any material;the control group(n=5)was implanted with mesoporous bioactive glass nanoparticles,and the experimental group(n=5)was implanted with mesoporous bioactive glass nanoparticles loaded with bone morphogenetic protein 2 osteogenic active peptide L20.Eight weeks after surgery,femoral Micro-CT scanning and tissue morphology observation were performed.RESULTS AND CONCLUSION:(1)Scanning electron microscopy showed that the mesoporous bioactive glass nanoparticles loaded with bone morphogenetic protein 2 osteogenic active peptide L20 were spherical and monodisperse particles.Transmission electron microscopy showed their porous structure with an average particle size of(268.10±0.58)nm,which could release L20 in vitro.(2)Mesoporous bioglass nanoparticles loaded with bone morphogenetic protein 2 osteogenic active peptide L20 were non-cytotoxic and could promote the proliferation and adhesion of bone marrow mesenchymal stem cells.Compared with the blank group and the control group,the alkaline phosphatase activity and extracellular matrix mineralization capacity of the experimental group were increased(P<0.05),and the mRNA expression levels of alkaline phosphatase,Runx2,and osteocalcin were increased(P<0.05).(3)The results of femoral Micro-CT scanning showed that compared with the blank group and the control group,the new bone mass and bone density of the experimental group were increased(P<0.05).The results of hematoxylin-eosin and Masson staining showed that compared with the blank group and the control group,the new bone formation and collagen fibers of the experimental group were increased.(4)These findings indicate that mesoporous bioactive glass loaded with bone morphogenetic protein 2 active peptide L20 exhibits excellent biocompatibility and in vitro and in vivo osteogenic properties,promoting regeneration and repair of SD rat femoral condyle defects.