影像指导内皮祖细胞基因干预治疗糖尿病并发脑梗死的实验研究

The benefits derived from stem cell transplantation in diabetic stroke models are limited. However, the effects of diabetic environment on exogenous transplanted stem cells are less investigated. Our previous results indicate that diabetes mellitus downregulates the number and function of exogenous endothelial progenitor cells (EPCs), but the mechanisms are still unclear. We hypothesize that diabetes mellitus may impair the function of transplanted EPCs by upregulating p38 MAPK signal pathway, which further lead to the limited efficacy of cell transplantation. To verify this hypothesis, we plan to specifically and efficiently downregulate the expression of p38 MAPK in cultivated EPCs through synthesizing lentiviral-mediated siRNA. Meanwhile, the cultivated EPCs will also be transferred into luciferase reporter gene and labeled with SPIO molecular probe. We aim to noninvasively and dynamically monitor EPCs homing, proliferation, and differentiation in diabetic stroke animals using MRI and bioluminescence imaging, which may provide an accurate method for in vivo cell tracking. Moreover, this project also aims to develop a one-stop MR evaluation system to investigate the role of p38 MAPK on EPC therapy in diabetic stroke animals, which may provide an efficient strategy for future clinical stem cell therapy in diabetic stroke.

在以糖尿病为基础疾病的脑梗死模型中干细胞疗效非常有限。而目前关于糖尿病活体环境对外源性移植干细胞影响的研究甚少。我们前期实验结果提示糖尿病环境对外源性内皮祖细胞EPCs数量及功能存在负性调节作用，但作用机制有待进一步探讨。为此，我们提出假说：糖尿病可能通过上调EPCs中p38 MAPK的表达影响细胞功能，导致疗效受限。我们将通过构建慢病毒载体在体外高效、特异下调EPCs中p38 MAPK基因表达，同时导入荧光素酶报告基因并经SPIO探针共同标记，采用超高场磁共振仪及生物发光成像仪，在糖尿病并发脑梗死模型活体水平无创、动态监测细胞归巢、增殖、分化情况，为干细胞准确活体示踪提供可行的方法；另外从细胞水平、脑白质结构、微循环、灌注水平等建立一站式活体评价体系，探讨p38 MAPK在糖尿病对外源性干细胞影响中的具体作用机制，为临床干细胞治疗糖尿病并发脑梗死提供有效的策略。