组织工程血管化是目前再生医学领域的研究热点与难点，外周细胞是近年来干细胞领域的研究热点，但是对于其分离纯化、分化调控及其在血管再生中的作用机制尚不清楚。本课题组前期研究证实脂肪间充质干细胞来源于微血管周围的外周细胞，并可以促进内皮细胞形成新生血管，Notch信号通路的变化可通过调节外周细胞或内皮细胞的相互作用，进而影响新生血管的形成。因此本课题拟研究Notch信号变化对外周细胞和内皮细胞的影响以及血管再生的调控。实验通过携带GFP标记的外周细胞与携带RFP标记的内皮细胞混合培养与三维胶原支架材料，构建血管再生三维模型；同时采用基因转染和生化抑制两种手段，上调/下调外周细胞或内皮细胞的Notch信号通路的表达，从正反两方面论证Notch信号对血管新生的调控作用，从而掌握血管再生的调控方法，在此基础上构建血管化组织工程骨，为骨组织工程血管化的机制研究提供理论和实验基础。

Vascularization is a key factor of regenerative medicine and tissue engineering. The vacularization needs the interaction between the pericytes and endothelial cells. Pericytes have been proved to be the origin of the mesenchymal stem cells which show the characters of both stem cells and blood vessel supporting cells. Our previous works have proved the adipose stem cells come from the pericytes and can enhace the vacularization of endothelials cells. Our preliminary study proved the upregulation of Notch of pericytes could increased the formation of fuctional blood vessels. So in this project we are trying to study the mechanism of Notch signal regulation on vascularization. We will use gene transfection or chemical reagent to regulate the Notch signal of pericytes and endothelial cells. Then we will study the gene and protein changes of the cells, such as Notch, Hes-1,Hey-1, HIF-1a, CXCR4, VEGF and so on. For the 3-D culture, pericytes marked with GFP and enthelial cells marked with RFP will be mixed in proper ratio and loaded on collagen gels. Live confocal fluorecent microscope technique will be applied to observe the formation of new blood vessel in vitro and in vivo. The red blood cells will be labeled by DIL dye and injected in the nude mice to study the fromation of fuctional blood vessels. This project will provide new idea and data about the regulation of vascularization based on Notch signal and pericytes.