Facilitated vascularization and enhanced bone regeneration by manipulation hierarchical pore structure of scaffolds
Facilitated vascularization and enhanced bone regeneration by manipulation hierarchical pore structure of scaffolds
复制标题
通过操纵支架的分层孔隙结构促进血管化并增强骨再生
DOI：
10.1016/j.msec.2019.110622
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发表时间：
2020-05-01
影响因子：
7.9
通讯作者：
Liu, Changsheng
中科院分区：
文献类型：
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作者：
Liu, Yang;Yang, Shengbing;Liu, Changsheng
在修复临界大小骨缺损的过程中，充分的血管化对于防止细胞死亡和促进宿主整合是非常重要的。多孔结构为血管的生长提供足够的空间是支架发展过程中必须考虑的问题。本研究以聚（3-羟基丁酸酯-co-3-羟基己酸酯）（PHBHHx）为材料，设计并制备了三种多孔结构支架，分别为具有大孔的单结构PHBHHx支架（PH-1）、具有大介孔的双结构PHBHHx支架（ph -2）和具有宏-微介孔的三结构PHBHHx支架（ph -3）。在体外研究了分层多孔支架对人脐静脉内皮细胞（HUVECs）的影响，如细胞附着、葡萄糖和乳酸检测、内皮标志物相关基因表达等。PHS-3支架在体外表现出较好的诱导血管生成的优先效力。因此，应用分层多孔支架加载rhBMP-2修复兔临界尺寸骨缺损（15 mm）。三维微计算机断层扫描（micro-CT）微血管成像分析显示，在4周和8周时，加载rhBMP-2的PHS-3 （PHS-3/rhBMP-2）缺损区域内的血管体积高于加载单一孔或双孔（PH-1/rhBMP2或PHS-2/rhBMP-2）的其他负载rhBMP-2多孔支架（PH-1/rhBMP2或PHS-2/rhBMP-2），说明多层多孔结构有利于营养传递和血运重建。通过显微ct、组织学和免疫组化分析进一步研究原位骨形成，证实PHS-3/rhBMP-2组的新骨形成速度最快。PHS-3/rhBMP-2诱导再生骨在12周时的最大负荷值为258.47 +/- 14.77 N，与正常骨的268.81 +/- 12.05 N无显著差异，提示在生物相容性支架中引入多级孔隙可能是促进血管生成和骨再生的有效途径。
Sufficient vascularization is quite important for preventing cell death and promoting host integration during the repair of the critical sized bone defects. Porous structure providing enough space for the ingrowth of vessels is an essential consideration during the scaffold's development. In this study, we designed and fabricated three kinds of porous structured scaffolds based on poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx), such as mono-structured PHBHHx scaffolds with macro pores (PH-1), di-structured PHBHHx scaffolds with macro-meso pores (PHS-2), and tri-structured PHBHHx scaffolds with macro-micro-meso pores (PHS-3), respectively. In vitro effects of the hierarchical porous scaffolds on human umbilical vein endothelial cells (HUVECs), such as cell attachment, glucose and lactate detection, relative gene expressions of endothelial markers were investigated. The PHS-3 scaffolds exhibited preferential potency of inducing better angiogenesis in vitro. Consequently, the hierarchical porous scaffolds were applied to load rhBMP-2 and repair the critical sized bone defect (15 mm) in rabbits. Microangiography analysis by three dimensional micro-computed tomographic (micro-CT) demonstrated that the volume of blood vessels within the defect area was higher in the rhBMP-2 loaded PHS-3 (PHS-3/rhBMP-2) than that in other rhBMP-2 loaded porous scaffolds with simplex or double scaled pores (PH-1/rhBMP2 or PHS-2/rhBMP-2) at 4 weeks and 8 weeks, which implied that multi-level porous structure was conducive to nutrition transmission and revascularization. Further investigations of orthotopic bone formation by micro-CT, histological and immunohistochemistry analysis confirmed the most accelerated new bone formation rate in the PHS-3/rhBMP-2 group. The maximum load value of the regenerated bone induced by PHS-3/rhBMP-2 at 12 weeks was 258.47 +/- 14.77 N which did not show significant difference from the normal bone of 268.81 +/- 12.05 N. These results highlighted that introducing multi-level pores into the biocompatible scaffolds may be an effective approach to promote angiogenesis and bone regeneration.