Electrosprayed Microparticles With PDNA Loaded Promote The Regeneration Of Blood Vessels

Disease caused from the ischaemic disease or blood vessel injury can not be cured satisfactorily by the traditional treatment. Promotting the revascularization by the method of gene transfection so as to express cytokine will be a valid means. First of all, finding a suitable gene vector is the important premise to fulfill the purpose. Electrospray can be used as a new method to prepare microspheres, with uniform size and morphology. In addition, calcium phosphate nanoparticles as a non-viral vector can be endocytosed easily and possess good biocompatibility. In our study, the pDNA/calcium phosphate nanoparticles-loaded electro sprayed microspheres have been prepared to express vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). The promotion of cell proliferation and secretion of extracellular matrices by microspheres have been studied on human umbilical vein endothelial cells (HUVEC) and smooth muscle cells (SMC). The promotion of vasculogenesis has been performed in vivo after subcutaneous implanration.pDNA/calcium phosphate nanoparticles were fabricated using the method of inverse microemulsion. The diameter of nanoparticle is about200nm and the encapsulation efficiency of pDNA were above70%. Calcium phosphate nanoparticles could control the release of pDNA, and the cytotoxicity of the pDNA/calcium phosphate nanoparticles was significantly lower than that of pDNA/PEI complexes. Then pDNA/calcium phosphate nanoparticles-loaded microspheres were prepared by means of electrospray, and the diameter was around375nm with uniform morphology. The encapsulation efficiency of pDNA is around47.2%and the formation efficiency of microspheres was about45.1%. The microspheres could protect the structural integrity of pDNA. Poly(ethylene glycol)(PEG) with different molecular weights was added into the polymeric substrate to adjust the release of pDNA in order to meet the demand of vasculogenesis. Compared with blend of microspheres and pDNA/calcium phosphate nanoparticles, pDNA/calcium phosphate nanoparticles-loaded microspheres possessed better biocompatibility. Importantly, the pDNA/calcium phosphate nanoparticles-loaded microspheres can promote HUVEC to secrete IV collagen and laminin and SMC to excrete I collagen and actin. In addition, the content of secretion of extracellular matrix in the group treated with2kinds of plasmid-loaded microspheres was higher than that of only one plasmid-loaded microspheres. pDNA/calcium phosphate nanoparticles-loaded microspheres were mixed into gel, which were implanted subcutaneously into SD rats. There was no significant difference in the microvessel density between the groups treated with blank nanospheres and blend of blank nanospheres and pDNA/calcium phosphate nanoparticles after4weeks, while the microvessel density of the groups treated with pDNA/calcium phosphate nanoparticles-loaded microspheres increased constantly, at the same time the vasculogenesis and maturity were more obvious for the groups treated with pVEGF and pbFGF/calcium phosphate nanoparticles-loaded microspheres.