Department of Neurology, First Affiliated Hospital of Harbin Medical University, Harbin, China.
Cell Biochem Funct. 2021 Oct;39(7):908-920. doi: 10.1002/cbf.3662. Epub 2021 Jul 22.
Increasing attention has been paid on the application of biodegradable materials such as magnesium and its alloys in neuron repair. AZ91D magnesium alloy coated with carbon nanotubes (CNTs) and/or calcium phosphate (CaP)/chitosan (CS) was fabricated in this study. To evaluate the bioactivity of these AZ91D-based composites, the extracts were prepared by immersing samples in modified simulated body fluid (m-SBF) for 0, 2, 8, 16, 24, 34, 44, 60, or 90 days. Immunofluorescence staining for neuronal class III β-tubulin (TUJ1) revealed that both CNTs-CaP/CS-AZ91D and CaP/CS-AZ91D extracts promoted axon outgrowth of dorsal root ganglia (DRG) neurons, accompanied with increased expression of phosphorylated focal adhesion kinase (p-FAK) and growth associated protein-43 (GAP-43). Besides, the extracts increased the expression and the release of neurotrophic factors including nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF). ERK signalling was activated in DRG neurons after treating with either CNTs-CaP/CS-AZ91D or CaP/CS-AZ91D extracts, and its inhibition with U0126 counteracted the beneficial effects of these extracts on DRG neuron. Overall, the extracts from these AZ91D-based composites might promote DRG neuron growth via activating ERK signalling pathway. Notably, CNTs-CaP/CS-AZ91D extracts showed a better promoting effect on neuron growth than CaP/CS-AZ91D. Assessment of ion elements showed that the addition of CNTs coating enhanced magnesium corrosion resistance and reduced the deposition of calcium and phosphorus on the surface of CaP/CS-AZ91D alloy. These findings demonstrate that CNTs-CaP/CS-AZ91D likely provide a more suitable environment for neuron growth, which suggests a potential implantable biomaterial for the treatment of nerve injury. SIGNIFICANCE: AZ91D magnesium alloy coated with carbon nanotubes (CNTs) and/or calcium phosphate (CaP)/chitosan (CS) was fabricated and their immersion extracts were prepared using modified simulated body fluid in this study. Both extracts from CNTs-CaP/CS and CaP/CS-coated AZ91D magnesium alloy promotes rat dorsal root ganglia (DRG) neuron growth via activating ERK signalling pathway. Notably, the addition of CNTs improves the performance of CaP/CS-AZ91D. For the first time, our research demonstrates that CNTs-CaP/CS-AZ91D likely provide a suitable environment for neuron growth, suggesting these AZ91D-based composites as potential implantable biomaterials for the treatment of nerve injury.
越来越多的人关注可生物降解材料（如镁及其合金）在神经修复中的应用。本研究制备了表面涂覆碳纳米管（CNTs）和/或磷酸钙（CaP）/壳聚糖（CS）的 AZ91D 镁合金。为了评估这些基于 AZ91D 的复合材料的生物活性，通过将样品浸入改良的模拟体液（m-SBF）中 0、2、8、16、24、34、44、60 或 90 天来制备提取物。免疫荧光染色神经元 III 型 β-微管蛋白（TUJ1）显示，CNTs-CaP/CS-AZ91D 和 CaP/CS-AZ91D 提取物均促进背根神经节（DRG）神经元的轴突生长，并伴随着磷酸化粘着斑激酶（p-FAK）和生长相关蛋白-43（GAP-43）表达增加。此外，提取物增加了神经营养因子包括神经生长因子（NGF）和脑源性神经营养因子（BDNF）的表达和释放。用 CNTs-CaP/CS-AZ91D 或 CaP/CS-AZ91D 提取物处理 DRG 神经元后，ERK 信号通路被激活，用 U0126 抑制其可拮抗这些提取物对 DRG 神经元的有益作用。总之，这些基于 AZ91D 的复合材料的提取物可能通过激活 ERK 信号通路促进 DRG 神经元生长。值得注意的是，CNTs-CaP/CS-AZ91D 提取物对神经元生长的促进作用优于 CaP/CS-AZ91D。离子元素评估表明，CNTs 涂层的添加增强了镁的耐腐蚀性，并减少了 CaP/CS-AZ91D 合金表面的钙和磷的沉积。这些发现表明 CNTs-CaP/CS-AZ91D 可能为神经元生长提供了更适宜的环境，这表明其可能是一种用于治疗神经损伤的可植入生物材料。意义：本研究通过使用改良的模拟体液制备了表面涂覆碳纳米管（CNTs）和/或磷酸钙（CaP）/壳聚糖（CS）的 AZ91D 镁合金，并制备了其浸出提取物。来自 CNTs-CaP/CS 和 CaP/CS 涂层的 AZ91D 镁合金通过激活 ERK 信号通路促进大鼠背根神经节（DRG）神经元生长。值得注意的是，CNTs 的添加改善了 CaP/CS-AZ91D 的性能。本研究首次证明，CNTs-CaP/CS-AZ91D 可能为神经元生长提供了适宜的环境，表明这些基于 AZ91D 的复合材料可能是治疗神经损伤的潜在可植入生物材料。
