The Cellular Response Of Biodegradable AZ31 Magnesium Stents In Rabbit Iliac Arterial Stenosed And Healthy Models

Biodegradable magnesium-based stents have become a research hotspot in the field of biodegradable vascular stents due to their good biocompatibility and biodegradable properties.At present,a large number of in vivo experiments have been carried out about magnesium-based stents at home and abroad.However,the evolution of the degradation products of magnesium-based stents throughout the degradation process,and the effects of degradation-produced soluble ions and solid-state degradation products on surrounding cells(such as endothelial cells,vascular smooth muscle cells,and inflammatory cells)are unclear.The interaction between magnesium-based stents and surrounding vascular tissues under the stenosed pathologic model is also unclear and no relevant literature has been reported.In this paper,the unilateral iliac artery of New Zealand white rabbit was injured by balloon,and two weeks of high-fat feed was fed after the operation,a stenosed iliac artery model was established.The H&E staining result showed that the stenosed model had intimal hyperplasia.The oil red staining result showed that there were some fat cells in the neointima area of the stenosed model.The immunofluorescence of CD31 & α-SMA showed that the intima of the stenosed model was injured and discontinuous.All of these results all confirm the success of the stenosed model.After establishing the stenosed model,AZ31 stents were implanted in the healthy model and the stenosed model respectively.The stented segments were analyzed by using a variety of histological staining and immunofluorescence staining methods.Magnesium-based stent was studied in the stenosed pathological vascular model for the first time.Results showed that there was intimal hyperplasia after stents implantation,it’s more serious in the stenosed model compared with the healthy model,the intimal thickness gradually decreased and the lumen area increased in the two models with the increase of implantation time.In the early stage of stent implantation,the endothelialization degree of the healthy model was higher than that of the stenosed model,but it was close to 100% after 1 year implantation.The vascular tissue in contact with the stent was infiltrated by calcium ions,the infiltration degree of calcium ions decreases over time.The smooth muscle cells in stented-segments have a tendency to transform into osteogenesis.No significant calcification was found ineither model.There was an acceptable inflammatory response after stent implantation,and the inflammation in the stenosed model was more severe compared with the healthy model,and the infiltration degree of inflammatory cells decreased with the implantation time.The results of SEM and EDS showed that AZ31 stent was fractured during degradation,and the position of the stent strut was gradually replaced by calcium and phosphorus degradation products.The purpose of this study is to provide more useful information for the in vivo evaluation of the magnesium-based stents.