目的:严重创伤性脑损伤(sTBI)引起的神经元丢失和脑萎缩是长期残疾的重要原因。脑细胞外基质(ECM)相关硫酸软骨素(CS)糖胺聚糖促进神经干细胞(NSC)的维持,和CS水凝胶植入物已经证明了增强神经保护的能力,在临床前sTBI研究中。然而,神经生成嵌合肽(CP)功能化CS水凝胶促进功能恢复的能力,在受控皮质撞击(CCI)和抽吸消融(SA)诱导的sTBI后,以前没有被证明。我们假设神经源性(CS)CP水凝胶将促进人类神经干细胞的神经生成,并加速sTBI大鼠脑组织修复和功能恢复。
方法:我们合成了4-O硫酸软骨素(CS-A)CP,和4,6-O-硫酸盐(CS-E)CP水凝胶,使用菌株促进的叠氮化物-炔环加成(SPAAC),促进人类神经干细胞的细胞粘附和神经突形成,体外;并评估(CS-A)CP水凝胶促进组织和功能修复的能力,在一个新的CCI-SAsTBI模型中,在体内。
结果:结果表明(CS-E)CP水凝胶通过粘着斑激酶复合物显着增强了人NSC的聚集和迁移,当与(CS-A)CP水凝胶中的NSC相比时,在体外。相比之下,NSC封装在(CS-A)CP水凝胶分化成带有较长神经突的神经元,并显示出更大的自发活动,当与(CS-E)CP水凝胶中的那些相比较时。(CS-A)CP水凝胶的腔内植入,在CCI-SA-sTBI之后,防止神经元和轴突丢失,通过免疫组织化学分析确定。与sTBI对照相比,(CS-A)CP水凝胶植入的动物还显示出明显加快的“伸手抓住”功能恢复,为期5周。
结论:这些发现证明了(CS)CP“点击”水凝胶的神经源性和神经保护特性,并为使用改良的CS双正交手柄开发用于sTBI修复的组织工程植入物开辟了新的途径。
Objective.Severe traumatic brain injury (sTBI) induced neuronal loss and brain atrophy contribute significantly to long-term disabilities. Brain extracellular matrix (ECM) associated chondroitin sulfate (CS)
glycosaminoglycans promote neural stem cell (NSC) maintenance, and CS hydrogel implants have demonstrated the ability to enhance neuroprotection, in preclinical sTBI studies. However, the ability of neuritogenic chimeric peptide (CP) functionalized CS hydrogels in promoting functional recovery, after controlled cortical impact (CCI) and suction ablation (SA) induced sTBI, has not been previously demonstrated. We hypothesized that neuritogenic (CS)CP hydrogels will promote neuritogenesis of human NSCs, and accelerate brain tissue repair and functional recovery in sTBI rats.Approach.We synthesized chondroitin 4-Osulfate (CS-A)CP, and 4,6-O-sulfate (CS-E)CP hydrogels, using strain promoted azide-alkyne cycloaddition (SPAAC), to promote cell adhesion and neuritogenesis of human NSCs,in vitro; and assessed the ability of (CS-A)CP hydrogels in promoting tissue and functional repair, in a novel CCI-SA sTBI model,in vivo. Main results.Results indicated that (CS-E)CP hydrogels significantly enhanced human NSC aggregation and migration via focal adhesion kinase complexes, when compared to NSCs in (CS-A)CP hydrogels,in vitro. In contrast, NSCs encapsulated in (CS-A)CP hydrogels differentiated into neurons bearing longer neurites and showed greater spontaneous activity, when compared to those in (CS-E)CP hydrogels. The intracavitary implantation of (CS-A)CP hydrogels, acutely after CCI-SA-sTBI, prevented neuronal and axonal loss, as determined by immunohistochemical analyses. (CS-A)CP hydrogel implanted animals also demonstrated the significantly accelerated recovery of \'reach-to-grasp\' function when compared to sTBI controls, over a period of 5-weeks.Significance.These findings demonstrate the neuritogenic and neuroprotective attributes of (CS)CP \'click\' hydrogels, and open new avenues for the development of multifunctional glycomaterials that are functionalized with biorthogonal handles for sTBI repair.