有机小分子NO2-供体的设计、合成及抗缺血性脑卒中活性研究

NaNO2对多种缺血性疾病疗效显著，其机理是：它在缺血部位可被还原为NO，产生血管舒张、细胞保护等缺血耐受作用，在正常组织被氧化为无毒NaNO3排出体外。但其代谢太快，高剂量或多次给药可引起过量的NO生成和钠离子摄入，产生毒副作用。我们致力于发展有机小分子NO2-供体来解决这一难题，已发现化合物ND1可经含巯基小分子作用，缓慢释放少量NO2-，减少大鼠脑缺血/再灌注(I/R)损伤，刺激缺血半暗带血管内皮细胞增殖，促进血管新生。本项目首先制备ND1衍生物/类似物I；再在它结构上引入葡萄糖和硫胺素片段得到II，使其在血脑屏障高表达的GLUT1介导下，转运并锁定于脑内；进一步将II修饰成腙/缩醛III，使其选择性地在脑缺血部位产生NO2-，再经还原释放NO。考察目标物的NO2-释放动力学、稳定性及脑靶向性，评价其抗I/R损伤的有效性和安全性，研究其作用机制，为获得抗缺血性脑卒中新药奠定坚实基础。

NaNO2 has displayed significant therapeutic effects for treatment of several ischaemic diseases. The mechanism of action is that it can be reduced to NO in the ischemic area, producing effects of ischemia tolerance such as vasodilatation, revascularization and cell protection, while in the normal tissues, NaNO2 can be oxidized to non-toxic NaNO3 excreted out of the body. However, the metabolism of NaNO2 is too rapid to control. High dose or multiple dosing can cause excessive NO generation and Na+ intake, leading to side effects. We have made effort to develop small organic molecular NO2- donors to address this issue, and found the compound ND1 slowly generates small amounts of NO2- in the presence of small molecules containing sulfydryl. Treatment with ND1 significantly mitigates brain ischaemia/reperfusion (I/R) injury and promotes angiogenesis by stimulating endothelial cell proliferation in the ischaemic penumbra in I/R rats. This project intends to prepare derivative(s)/analogue(s) I of ND1, to synthesize compound(s) II by introduction of glucose and thiamine disulfide groups to the structure of I, which can be transferred and fixed into the brain via a transportation mediated by GLUT1 highly expressed in blood brain barrier, and to synthesize hydrazone/acetal compound(s) III by structural modification of II, which can selectively release NO2- and further be reduced by the enzyme into NO in ischemic area. We will examine the NO2- releasing dynamics, stability and brain targeting ability of the compounds, evaluate their efficacy and safety of anti-I/R injury, and study their mechanisms of action at the cellular and molecular levels. The successful implementation of the project will lay a solid foundation for discovery of new anti-ischemic stroke drug(s), and meanwhile provide a novel strategy for treatment of other ischemic diseases.