一种新型硫化氢长程控释纳米探针的构建及其在心肺复苏后心脑器官联合保护中的应用

It has been widely accepted that hydrogen sulfide (H2S) acts combinational protective effects to heart and brain in patients suffering from restoration of spontaneous circulation (ROSC) after cardiac arrest (CA) via many mechanisms. However, traditional H2S donors (such as sodium hydrosulfide) are either increasing H2S level too rapidly or hardly to be regulated, which largely limits in vivo application of H2S. In our previous study, a controllable releasing H2S system was synthesized based on mesoporous silica nanoparticle, which is particularly suitable for in vitro application. Utilizing exploited methods, the present study will employ the modified mesoporous ferric oxide nanoparticle as the carrier of the H2S donor diallyl trisulfide, and a novel stable, biocompatible, trackable, long-range and controllable H2S-releasing nanoprobe is expected to be synthesized, which can slowly and physiologically release H2S in vivo, with good biocompatibility and receptor mediated brain-targeted effect, as well as the ability to be real-time traced by MRI. We will further study the protective effects of the novel controllable H2S-releasing nanoprobe to both heart and brain using cardiomyocytes and neuron hypoxia/reoxygenation models and rat CA/ROSC model. This study will provide a unique platform for controlled release of H2S in vivo, and offer a new method for combinational myocardial and cerebral protection from ischemia and reperfusion injury, bringing considerable benefits for CA/ROSC patients.

研究证明，新型气体信号分子—硫化氢具备心肺复苏后心脑器官联合保护的作用。然而，以硫氢化钠为代表的传统硫化氢供体具有释放迅速、不稳定和难以调节等特点，这一定程度上限制了硫化氢的治疗应用。在前期工作中，我们成功制备了适于体外应用的硫化氢控释纳米硅材料。本项目基于已开发技术，拟将生物可降解的介孔氧化铁纳米粒子作为载体，通过表面修饰和纳米载药，构建一种新型稳定、无毒、可追踪、并具备一定脑靶向作用的硫化氢长程控释纳米探针，其可在体内缓慢而可控的释放硫化氢，符合生理情况；同时具备良好的生物安全性和受体介导的脑靶向性，并可通过磁共振体外实时追踪。我们拟将此探针应用于大鼠心肌细胞/神经元细胞的缺氧-复氧模型和大鼠心跳骤停-心肺复苏模型，评价其对心脑器官联合保护的效果及与传统硫化氢供体对比的优势。本项目的顺利实施将为硫化氢的体内研究创造良好的平台，更为心肺复苏后心脑器官联合保护提供新的手段，以造福病人。

新型气体信号分子硫化氢（H2S）具备心肺复苏后心脑器官联合保护的作用。然而现有的H2S供体具有释放迅速、不稳定或难以调节等特点。此项目使用已开发的H2S纳米缓释技术，将生物可降解的介孔氧化铁纳米粒子作为载体，通纳米载药和表面修饰，构建了一种新型稳定、无毒、可追踪、并具备一定脑靶向效果的H2S长程控释纳米探针（Fe2O3-DPL），其可在体内循环中缓慢释放H2S，同时具备良好的生物安全性和受体介导的脑靶向性，并可通过MRI实时追踪。制备的Fe2O3粒子平均直径200nm，纳米孔径2nm，比表面积821 m2/g，有效负载DATS（载药率48%、包封率95%），并由乳铁蛋白有效修饰。其体内注射后在体内体现出良好的生物安全性，MRI和荧光评价发现其明确的脑靶向性。其在血浆和心、脑器官中缓慢释放H2S（0h: 血浆0.63μM，脑组织0.52μmol/g，心肌0.41μmol/g；4h：血浆1.42μM，脑组织0.67μmol/g，心肌0.52μmol/g；24h：血浆0.91μM，脑组织0.63μmol/g，心肌0.50μmol/g；7d：血浆0.75μM，脑组织0.59μmol/g，心肌0.44μmol/g），比NaHS、DATS等更加持久。将其应用于大鼠心肌细胞/神经元细胞的缺氧（4h）-复氧（6h）模型，评估得Fe2O3-DPL具备改善的心肌细胞和神经元细胞活力；将其静脉注射于大鼠心跳骤停-心肺复苏中，24h评估结果发现Fe2O3-DPL具备最佳的EF值和神经功能缺损（NDS）评分；伴随明确减少心梗面积和脑梗死面积infarct area/area at risk。同时，Fe2O3-DPL可减轻心脑器官的炎症反应、氧自由基产生、心肌细胞和神经元细胞凋亡，并保护心脑线粒体功能。本项目拓展了纳米材料在H2S研究中的应用领域，推动H2S在体内治疗中的应用研究，并为心肺复苏后心脑器官联合保护提供了新的手段。