Atherosclerosis Model In Minipigs And Study On The Effect Of The Vascular Stent Of Biodegradable Magnesium Alloy

At present,cardiovascular diseases have become one of the most important reasons that lead to human death.Stenting is an important means to save the life of cerebral and myocardial patients in critically.Metal stents imported cannot be absorbed and very expensive,in addition to staying in the body for a long time,it can also cause damage to the vascular endothelial cells and has a long-term effect on the blood vessels and lead inflammatory reaction which cause the proliferation of vascular smooth muscle cells and subacute thrombus reaction,and eventually lead to vascular restenosis.Biodegradable stents can reduce or avoid such drawbacks due to it can be absorbed by body.In view of the stent used in myocardial infarction and cerebral infarction and other diseases caused by atherosclerosis,in this paper,we establishment the animal model of atherosclerosis in miniature pigs,so as to place biodegradable magnesium alloy stent JDBM to body under the condition of the most close to the clinical onset and to lay the foundation for the further study of theory of JDBM and the process of its industrialization through observing the endothelialization process,proliferation and migration of vascular smooth muscle cell,The diameter of blood vessel,the unit area of neointima,the change of elastic layer,the distribution of inflammatory cells,the expression of inflammatory products and the degree of its degradation.The results showed that the atherosclerosis model could be successfully replicated in four months with the method of feeding high fat diet combined with balloon injuried.There was no significant difference between the JDBM stent and 316 L SS in diameter of blood vessel thirty days later,the vessel in 316 L SS group was blocked up after ninety days,diameter of blood vessel in JDBM group is smaller than that of thirty days and sixty days,so,JDBM has a lower rate of restenosis.Staining elastic fiber to observe the change of inner elastic layer,there was no significant difference between the two groups after thirty days and sixty days,but the elastic layer disappeared completely in the 316 L SS group at the time of the ninety day,in contrast,the JDBM stent has less damage and less traction to the vascular structure.Scanning electron microscope was used to observe the endothelialization of stent,and there was no significant difference between the two groups,however,the surface of 316 L SS gathered more platelets,which was more likely to cause inflammatory reaction.From the perspective of degradation rate,JDBM stent has been degraded after sixty day,inner diameter of stent has ruptured,the side close to the heart has nearly degradated completely after ninety day,other parts keep the original shape basically.This experiment is the first time in China to use the model of atherosclerosis in miniature pigs which is close to the human pathological environment to implanting stent.The superiority of JDBM stent in restenosis rate,biocompatibility,biodegradability and safety was verified from various aspects.