Study On The Inflammatory Response Of Fibroin Small-caliber Vessels Implanted In Animals

In vivo transplantation studies,local inflammatory response or immune stimulation is an important part of exploring the reaction between materials and the body.The grafting of artificial blood vessels into the body is a traumatic process that causes damage to the body.The foreign body reactions produced are mainly divided into:(1)acute inflammatory reaction stage,infiltration of congenital cells such as granulocytes and monocytes/macrophages after wounds.The site is responsible for removing cell debris to prevent bacterial infection.(2)The repair stage mainly refers to the damage repair of the implant site.After transplantation of artificial blood vessels in vivo,the inflammatory reaction is mainly involved in the stage of tissue damage repair,involving various cell types such as neutrophils,monocytes,macrophages,lymphocytes,and adsorption of some biomolecules such as proteins,white blood cells.Adhesion and activation,expression of cytokines,tissue remodeling,and formation of fibrous cysts.The previously prepared silk fibroin small-caliber blood vessels have been shown to be in situ regenerated in animals.In order to further analyze the influencing factors of tissue regeneration,this article explored the inflammatory response of this small-caliber blood vessel as a blood vessel implanted in animals.After transplantation of small blood vessels into the common carotid artery of rabbits,the adhesion,infiltration and expression of related cytokines of inflammation-related cells(neutrophils,macrophages,lymphocytes)in small vessel stents were investigated.In-depth understanding of in situ tissue regeneration or reconstitution of silk fibroin small-bore vascular animals.Firstly,the silkworm raw silk was degummed,dissolved and dialyzed,and the silk fibroin aqueous solution was combined with the tubular fabric to simulate the structure of the natural blood vessel.A 3 mm inner diameter silk fibroin small-caliber blood vessel was prepared,and the rabbit common carotid artery was implanted by end-to-end anastomosis.After the implantation,the material is taken at the time of planning.Secondly,after the small-caliber vascular implantation of silk fibroin,blood test was performed at a given time to initially evaluate the inflammatory phenomenon in rabbits.The distribution and dynamic changes of neutrophils,macrophages and lymphocytes on the scaffold were observed by HE staining..The three-category blood routine showed that there were more lymphocytes in the blood transplanted to one month,and the number of white blood cells exceeded the conventional index range from three months to twelve months after transplantation.The results of biochemical analysis showed that the content of C-reactive protein was higher on the first day of implantation,and decreased significantly after one week.After three months of transplantation,C-reactive protein was highly expressed.The results of HE staining showed that there were more neutrophils in the end and one and three days of implantation,and the least neutrophils were implanted in one month,increased in three months,and then gradually decreased.At the time of initial creation,the number of macrophages was not much,and it increased significantly after one week,but the number of one month decreased and stabilized.Lymphocytes were less abundant than the other two cells,but during the process of tissue regeneration,lymphocytes changed significantly during the nine months.The changes in the number of cells in the middle segment were similar to those in the end,but the three inflammatory cells at the end increased at three months of implantation.Thirdly,the expression levels of inflammatory cell-related factors showed dynamic changes.At the time of initial creation and one week of implantation,more expression of cathepsin G and CD68 were found in the middle of the scaffold.At one month,the positive expression of the two factors in the scaffold After the spot was the least,the positive expression of cathepsin G was gradually increased,and the positive expression of CD68 was more stable in six months.At the time of initial creation,the positive expression spots of CD3 in the scaffold were few,only relatively more expressed in one week,and there was a significant increase in the three months after implantation,and then decreased relatively.After one month of implantation,the small vessel material has not begun to degrade,and because of the severe trauma of the end anastomosis,more inflammatory cells are recruited,so the positive expression of cathepsin G and CD68 is more than the middle segment.After three months,the material degraded,new tissue formed,and the difference in the number of positive expression spots of these factors in the end and middle segments was reduced.Finally,real-time quantitative PCR was used to analyze the phenotypic differentiation of macrophages after stent implantation.The results showed that the expression level of pan-macrophage-specific factor CD68 in silkworm small-cavity vessels was about 2.2-4 times that of autologous blood vessels.The expression level of M1 macrophage-specific factor CD80 was higher than that of autologous blood vessels at one day,two weeks,and one month,which were 1.06 times,1.2 times,and 1.29 times,respectively.In contrast,the expression level of macrophage-specific factor CD 163 increased 2.4-fold in the two weeks before implantation and was higher in the three-month and nine-month,indicating M2 macrophages,The dominant role in the whole transplantation process also indicates that the silk fibroin material small blood vessel scaffold can promote the differentiation of macrophages into M2 anti-inflammatory macrophages that are beneficial for tissue repair.