实时响应血糖的壳聚糖载药体系应用于颌骨缺损修复研究

The repair and regeneration of maxillofacial bone defect under hyperglycemia condition becomes a big challenge in dental clinical. Theoretically, insulin treatment combined with the glucose sensitive drug controlled delivery system provides a new way to solve this problem. However, this system still exists some drawbacks such as limited sensitivity, unfavorable drug release and low mechanical strength. In this study, a novel crosslinked fiber membrane with core-shell structure will be fabricated using electrospinning technology. Specifically, tumor necrosis factor-α antibody is selected as the core as well as quaternized chitosan and nano-hydroxyapatite as the shell to decrease the primary drug burst and increase the membrane's mechanical strength. Then, glucose oxidase will be immobilized on the shell through chemical bond to obtain real-time glucose sensitivity. After that, biodegradation ability and drug release of this system will be evaluated in-vitro. Then, this material will co-culture with bone mesenchymal stem cells to investigate the related protein expression from inflammation or osteogensis process. At last, This system will be implanted into maxillofacial bone defect of diabetic rat model to evaluate whether it can improve the bone regeneration under hyperglycemia circumstance. The aim of this study is to obtain a promising and feasible real-time glucose sensitive drug controlled delivery system to repair and regenerate the maxillofacial bone defect such as periodontal or peri-implant bone defect for hyperglycemia patients. In addition, this study is also helpful to find out the related mechanism of maxillofacial bone regeneration under hyperglycemia circumstance.

高血糖患者缺损颌骨的再生一直是临床亟待解决难题。全身降糖与局部血糖响应载药体系联合应用为解决上述问题提供了新思路，但目前该体系血糖响应灵敏度不高、释药持续时间短及力学性能欠佳。本项目拟将炎症肿瘤蛋白因子α抗体作为药物模型成核，季铵化壳聚糖-纳米羟基磷灰石复合物为壳，采用电纺技术制备核壳结构的交联纤维膜，以缓解药物突释现象并提高膜材料力学强度；通过化学接枝将葡萄糖氧化酶固定在壳表面实现血糖响应功能，研制可降解的血糖实时响应载药体系。体外考察该体系在高葡萄糖环境下降解和释药过程，并与骨髓间充质干细胞共培养检测炎症及成骨的相关蛋白表达水平；采用糖尿病大鼠颌骨缺损模型，评价该载药体系影响高血糖下缺损颌骨再生状况。本项目有望得到一种能促进颌骨缺损修复的血糖实时响应载药体系，为高血糖患者牙周、种植体周等颌骨缺损修复临床治疗提供切实可行的手段，并有助于探讨高血糖患者颌骨再生的相关机制。

研究背景：糖尿病患者的缺损颌骨修复一直是临床亟待解决的难题之一。主要原因在于高血糖微环境可加重炎症反应，抑制成骨相关细胞的迁移、增殖及成骨向分化，对新骨再生产生不利影响。针对上述问题，临床上普遍采用的治疗方法虽能取得一定效果，但依然存在药物的生物利用率低、抗生素使用存在争议等问题，并且口服方式容易给患者造成一定的毒副作用。血糖响应型药物控释载体能够实时感应周围微环境血糖浓度变化，并随之调节自身结构，从而控制携载药物按需释放，最终提升糖尿病相关并发症的治疗效果。.研究方法与结果：本项目为糖尿病患者的颌骨缺损修复提供了一种新的治疗策略。我们首先利用同轴电纺技术制备载重组人骨形态发生蛋白（rhBMP-2）的核-壳结构电纺纤维膜，并利用化学接枝的办法在其表面固定GOD以赋予材料血糖响应特性。接下来，我们通过一系列的手段对材料相关的理化性能进行了表征。结果表明a). 同轴电纺技术可以成功获得核-壳结构纳米电纺纤维；b). 通过化学固定GOD的方式相比于物理吸附能够有效提升酶的粘接性能以及稳定性，同时其活性未受到太大影响；c). 纤维具有良好的血糖响应性，高葡萄糖糖浓度能够有效提升携载的rh-BMP2释放速率和累积释放量；d). 该纤维相比于对照组可促进mBMSCs成骨向分化，同时动物实验表明该材料能够提升糖尿病大鼠的颌骨缺损修复效果。. 在上述研究基础上，项目组也开展了光交联血糖敏感水凝胶体系用于糖尿病牙周炎的体外研究。结果表明该药物载体的生物相容性得到明显改善，同时其良好的血糖敏感性确保其能够在高糖环境下抑制牙周炎致病菌牙龈卟啉单胞菌的增殖，并且葡萄糖浓度越高，其抑菌效果越好。.结论：本项目得到了一种能促进骨再生，提升颌骨缺损修复效果的实时响应血糖的药物控释体系，为高血糖患者牙周、种植体周等颌骨缺损修复临床治疗提供切实可行的手段，并有助于探讨高血糖患者颌骨再生的相关机制。