Continued sustained release of VEGF by PLGA nanospheres modified BAMG stent for the anterior urethral reconstruction of rabbit

ABSTRACT

OBJECTIVE@#To study the biocompatibility and neovascularization of the PLGA nanospheres wrapped with vascular endothelial growth factor (VEGF), which can improve bladder acellular matrix graft (BAMG) with local continuous release of VEGF.@*METHODS@#A total of 18 rabbit model (length of stenosis 3 cm) with anterior urethral stricture were used as experimental animals and divided into three groups. Group A as the control group Simple BAMG scaffold materials for urethral reconstruction. Group B as the blank group PLGA microspheres modified BAMG for urethral reconstruction. Group C PLGA conjugated with VEGF and modified BAMG for the urethral reconstruction. All rabbits underwent urethral angiography after 7 days, 15 days, 1 month and 3 months after the operation, and one rabbit in each group was sacrificed to be prepared for the organization histologic examination, HE staining, masson staining, CD31, 34 and a-SAM immunohistochemical detection in the repaired sites.@*RESULTS@#In group A, significant urethral restenosis occurred in two rabbits after 15 days of the operation, HE and masson staining showed a lot of collagen arranged in the repaired sites, and there were a large number of inflammatory cell infiltration, and there were also CD31, 34 in the repaired sites. a-SAM microvascular tag count showed a small amount of microvascular; Group B showed anastomotic restenosis, HE and masoon staining showed inflammatory cell infiltration and collagen deposition; Group C urethrography showed lumen patency. There were a small amount of inflammatory cell infiltration after 7 and 15 days after the operation, and there were also CD31, 34 in the repaired sites. The a-SAM microvascular tag count showed many microvascular. And the difference was significant.@*CONCLUSIONS@#Anterior urethral reconstruction with sustained-release of VEGF by PLGA nanospheres modified BAMG stents can reduce postoperative restenosis. It can also reduce collagen deposition and scar formation, promote angiogenesis of the repair tissue; therefore it in valuable in the tissue-engineered urethral reconstruction.