Abbasi Naghmeh, Lee Ryan S B, Ivanovski Saso, Love Robert M, Hamlet Stephen
School of Dentistry and Oral Health, Griffith University, Gold Coast Campus, Southport, Queensland 4215 Australia.
Menzies Health Institute Queensland, Griffith University, Gold Coast Campus, Southport, Queensland 4215 Australia.
Biomater Res. 2020 Oct 1;24:17. doi: 10.1186/s40824-020-00196-1. eCollection 2020.
Biomaterial-based bone tissue engineering represents a promising solution to overcome reduced residual bone volume. It has been previously demonstrated that gradient and offset architectures of three-dimensional melt electrowritten poly-caprolactone (PCL) scaffolds could successfully direct osteoblast cells differentiation toward an osteogenic lineage, resulting in mineralization. The aim of this study was therefore to evaluate the in vivo osteoconductive capacity of PCL scaffolds with these different architectures.
Five different calcium phosphate (CaP) coated melt electrowritten PCL pore sized scaffolds: 250 μm and 500 μm, 500 μm with 50% fibre offset (offset.50.50), tri layer gradient 250-500-750 μm (grad.250top) and 750-500-250 μm (grad.750top) were implanted into rodent critical-sized calvarial defects. Empty defects were used as a control. After 4 and 8 weeks of healing, the new bone was assessed by micro-computed tomography and immunohistochemistry.
Significantly more newly formed bone was shown in the grad.250top scaffold 8 weeks post-implantation. Histological investigation also showed that soft tissue was replaced with newly formed bone and fully covered the grad.250top scaffold. While, the bone healing did not happen completely in the 250 μm, offset.50.50 scaffolds and blank calvaria defects following 8 weeks of implantation. Immunohistochemical analysis showed the expression of osteogenic markers was present in all scaffold groups at both time points. The mineralization marker Osteocalcin was detected with the highest intensity in the grad.250top and 500 μm scaffolds. Moreover, the expression of the endothelial markers showed that robust angiogenesis was involved in the repair process.
These results suggest that the gradient pore size structure provides superior conditions for bone regeneration.
基于生物材料的骨组织工程是克服残余骨量减少的一种有前景的解决方案。先前已经证明，三维熔融电写聚己内酯（PCL）支架的梯度和偏移结构能够成功引导成骨细胞向成骨谱系分化，从而实现矿化。因此，本研究的目的是评估具有这些不同结构的PCL支架在体内的骨传导能力。
将五种不同的磷酸钙（CaP）涂层熔融电写PCL孔径支架：250μm和500μm、500μm且纤维偏移50%（offset.50.50）、三层梯度250 - 500 - 750μm（grad.250top）和750 - 500 - 250μm（grad.750top）植入啮齿动物临界大小的颅骨缺损处。将空白缺损用作对照。在愈合4周和8周后，通过微计算机断层扫描和免疫组织化学评估新骨情况。
植入8周后，grad.250top支架中显示出明显更多的新形成骨。组织学研究还表明，软组织被新形成的骨替代并完全覆盖了grad.250top支架。而在植入8周后，250μm、offset.50.50支架和空白颅骨缺损处的骨愈合未完全发生。免疫组织化学分析表明，在两个时间点所有支架组中均存在成骨标志物的表达。在grad.250top和500μm支架中检测到矿化标志物骨钙素的强度最高。此外，内皮标志物的表达表明强大的血管生成参与了修复过程。
这些结果表明，梯度孔径结构为骨再生提供了优越条件。
