新型共载FGF13和NGF的温敏型肝素-泊洛沙姆水凝胶对外周神经损伤修复的作用研究

Peripheral nerve injury (PNI) has became an urgent problem in the world. Recent studies have shown that the mainly reasons that caused an unsatisfactory nerve repairing effectiveness are including microenvironmental disturbance, growth factor (GFs) deficiency and axonal regenerative disorder. Thus, present strategies that enhance PNI repairing are mainly focused on creating a optimal microenvironment, administrating different kinds of exogenous GFs and promoting axon regeneration. Our previous research have demonstrated that fibroblast growth factor 13 (FGF13) possessed the able that promoted axonal growth and nerve repair through maintaining microtubule stabilization. Nerve growth factor (NGF) as the first isolated polypeptide proteion was shown to accelerate myelin debris clearance and protected the damaged neurons. Based on those facts, this project develops a new type of a thermo-sensitive hydrogel platform to co-deliver FGF13 and NGF via physical crosslinking. This GFs-HP hydrogel has the potential for creating a optimal microenvironmentnot that favors axonal regrowth and remyelination through the extensive roles of GFs. At the same time, heparin-containing hydrogel can localize and continuously release double GFs in a steady fashion, which ensure the requirement of GFs amount for nerve regeneration. The procedures of this project are as follows: ①Firstly, we try to construct the optimal hydrogels with best mass ratio and evaluate its material properties; ②Then, we will administrate this GFs-HP hydrogle to the sciatic nerve transection model and test its safety and effectiveness through electrophysiology, histopathology, molecular biology and so on; ③Lastly, using transwell technology, we co-culture neurons and vascular endothelial cells to explore the effects of this hydrogle on facilitating remyelination, neuroprotection and neuroregeneration. Overall, the technologies on "biological scaffold materials", "biological factor" and "targeted delivery system" in this project are combined together to provide the compound therapy for the recovery of PNI.

外周神经损伤(PNI)是亟待解决的难题之一，微环境紊乱、生长因子(GFs)不足和轴突再生缓慢是PNI难治愈的主要原因。因此，改善神经生长的微环境、补充多种GFs和促进轴突再生是治疗PNI的重要策略。我们前期的研究结果表明，成纤维细胞生长因子13(FGF13)可增强微管稳定从而促进轴突生长和神经修复，神经生长因子(NGF)能够加速髓鞘碎片的清除并保护受损的神经元。本项目将肝素-泊洛沙姆水凝胶(HP)共载FGF13和NGF，形成新型GFs-HP温敏型水凝胶，发挥改善微环境、促神经保护和神经生长等多重功效：①构建最佳质量配比的水凝胶并评价材料学特性；②制备坐骨神经横断动物模型，利用电生理、组织病理学、分子生物学等方法检测其安全性和有效性；③利用神经元和血管内皮细胞共培养体系，探讨其促再髓鞘化，保护神经元和促血管生成等作用。本项目将生物材料、生长因子、制剂多学科技术融合，为PNI治疗提供复合疗法。

外周神经损伤（PNI）是亟待解决的临床医学难题。目前，生长因子（GFs）类药物被认为是修复PNI的重要措施之一。本项目利用前期合成的肝素-泊洛沙姆水凝胶（HP）包载GFs并探讨其材料学性质及对糖尿病外周神经损伤（PNI-diabetics）的修复作用。我们重点研究了神经生长因子（NGF）和成纤维生长因子13（FGF13）对早期PNI的修复效果并揭示其潜在的作用机制。研究结果显示，HP具有良好结合多种GFs的特性，包括NGF和FGF13，并缓控它们的释放，同时，包裹单一因子的NGF-HP可有效地促进PNI-diabetics大鼠运动功能的恢复并显著提高损伤神经内部轴突的再生和功能蛋白的表达，并且，抑制由糖尿病诱导的脱髓鞘病变。进一步，我们的研究发现外源性NGF能够良好地促进早期PNI的神经再生，并且，这种作用主要是NGF通过P75NTR/AMPK/mTOR信号通路激活血旺细胞（SCs）内的自噬水平并保持自噬流的通畅，进而加速SCs对髓鞘碎片的清除来实现。另外，我们的研究结果还揭示了FGF13能够有效地促进PNI大鼠后肢的运动和感觉恢复、轴突再生及再髓鞘化，并且，这些作用与维持SCs内微管的稳定密切相关。这些结果为揭示GFs修复PNI的潜在机制提供了新思路。在Theranostics等国际期刊发表研究性论文5篇并授权发明专利1项等。