具有干预脑出血术后铁超载和再出血功能的新型脑植入剂构建及其止血机制研究

Intracerebral haemorrhage (ICH) is an important public health problem leading to high rates of death and disability in the world. Surgery has been one of the main for treating ICH, but the value of surgical treatment is disputed, because there is no overall benefit from early surgery when compared with initial conservative treatment. Based on the two important factors influencing the surgical outcome of ICH: postoperative bleeding and secondary brain injury resulting from iron overload, the iron chelator-loaded keratin hemostatic gel will be fabricated via material science, physiology, pharmaceutical and clinical medicine technologies, which will be used to improve the therapeutic effect of surgical treatment by intervening the bleeding and iron overloaded simultaneously. The ICH occurs by infuse the collagenase into rat caudate nucleus, and the postoperative iron overload in damage field can be formed via infuse the autologous blood into rat caudate nucleus followed by microinvasive hematoma removal operation, which is used to investigate the hemostatic effect and iron remove capacity of the prepared keratin gel, respectively. In addition, the effect of keratin gel in alleviating the secondary brain injury will be also evaluated by behavior, brain water content, histology, nuclear magnetic resonance scanning and proteins expression level analysis. And the dynamic formation mechanism of high viscosity gel will be studied based on the features of biomaterial that the rheological property of keratin gel will be changed after absorbed the blood and then accelerate the hemostatic process. This program can supply a new therapeutic strategy and establish an experimental basis for ICH, which also provide a novel basis for the design and development of biological hemostatic materials.

脑出血是全球范围内致残和致死的重要原因之一。外科手术虽已成为脑出血治疗的重要手段，但由于手术预后与保守治疗相比无明显改善，因此其治疗价值一直饱受争议。基于脑出血术后再出血和铁超载引起继发性脑损伤两大重要影响因素，运用材料学、生理学、临床医学等技术手段，构建载铁离子螯合剂的角蛋白止血凝胶具有双重干预再出血和铁超载的潜力，有望提高脑出血的手术治疗效果。本项目将分别采用大鼠尾状核注入胶原酶引发脑出血和自体血注入后微创血肿清除在损伤区域形成铁超载，考察载去铁胺角蛋白凝胶的止血和铁离子清除性能；通过动物神经功能评定、核磁共振扫描、组织观察、脑含水量、相关基因与蛋白表达等方面分析植入凝胶对继发性脑损伤的缓解作用，并以角蛋白凝胶吸收血液后流变性能改变加速止血进程为出发点，探讨高粘性凝胶的动态形成机制。本项目可为脑出血的治疗提供新策略并奠定实验基础，同时也为新型生物止血材料的设计与开发提供新的理论基础。

外科手术作为治疗脑出血的重要手段，但其治疗价值一直存在诸多争议，主要原因是外科手术预后与保守治疗相比无明显改善。本项目基于脑出血术后再出血和铁超载引起继发性脑损伤两大重要影响因素，成功构建了载铁离子螯合剂的角蛋白凝胶作为脑出血术后原位治疗。首先，角蛋白凝胶在血肿清除手术后植入脑内可使损伤区域的铁离子在30min内达到正常生理水平，将原位注射螯合剂的剂量（20 μg）降低至静脉注射剂量（15 mg）的1/750，原位治疗仍可表现出更优的铁离子清除和神经功能恢复效果。角蛋白凝胶在脑内具有良好的生物相容性和生物降解性，4周基本可降解完全。其次，角蛋白凝胶对于不同剂量胶原酶诱导的不同程度的脑出血都具有显著的止血效果，能够明显降低血肿体积。通过角蛋白凝胶止血治疗显著减轻了病灶区脑组织液化坏死和神经元细胞的凋亡，能有效抑制病灶周围星形胶质细胞的反应性增生，减少神经炎症反应，从而降低脑组织损伤。再次，以角蛋白与血液接触后会形成高粘度的凝胶为出发点，考察了不同介质与角蛋白形成凝胶后粘弹性变化，发现全血和血浆的粘弹性最高；进而使用单一组分的重组角蛋白进行止血机制研究，发现角蛋白的止血机制是加速纤维蛋白原向纤维蛋白转变，进而达到快速止血的目的。此外，本项目还进行了角蛋白在快速止血和组织方面研究。项目实施不仅为脑出血的预后提高提供了一种全新的治疗策略，止血机制研究还为新型角蛋白产品开发提供了理论和实验基础。