Study On Angiogenesis Of Full-thickness Burn Wounds Repaired With Artificial Dermal Stent Encoding Dragon's Blood

Study on angiogenesis of full-thickness burn wounds repaired with artificial dermal stent encoding dragon's bloodObjective This paper is to investigate the effect of collagen-chitosan artificial dermal stent encoding different concentrations of dragon's blood on repair of full thickness burn wound, and to determine the effect of dragon's blood on angiogenesis of the wound after the artificial dermal stent transplantation.Methods Wounds and pathological changes were observed in 1,2, and 3 weeks after the collagen-chitosan porous scaffolds encoding two different concentrations of dragon's blood (1g/L and 4g/L) were respectively transplanted on wounds of full thickness burn wounds with debriment in 6 Bama miniature pigs (altogether 12 pigs in 2 groups), and so was done the wound healing after epidermis had been grafted for 2 weeks on surface of different dermal scaffolds transplanted on wounds for 2 weeks. At same time, new-forming vessels expressing CD31 and mature vessels expressing a-SMA and the expression of VEGF in wounds of different time were detected in situ by immunohistochemical staining and immunofluorescence double staining. The burn wounds with he collagen-chitosan porous scaffolds and without any scaffold transplantation were studied as the control.Results①Observations of wound and wound repair after after epidermis grafting:Wounds in 1,2, and 3 weeks after the collagen-chitosan porous scaffolds encoding two different concentrations of dragon's blood transplantation were different from granulation wounds. Angiogenesis of the collagen - chitosan porous scaffold encoding higher concentration of dragon's blood was better than that of the collagen-chitosan porous scaffold encoding lower concentration of dragon's blood. Survival rates of epidermis graft were 100% and 90% respectively after the epidermis had been grafted for 2 weeks on surface of the scaffold encoding higher or lower concentration of dragon's blood which had been transplanted for 1,2 and 3 weeks, however, the survival rate of epidermis was only 60%-70% after the epidermis had been grafted for 2 weeks on surface of the scaffold without dragon's blood.②Pathological observation:Neo-forming micro-vessels in different wounds had increased from 1 to 3 weeks after three different scaffolds were transplanted. Neo-forming micro-vessels in the wound repaired with the scaffold encoding higher concentration of dragon's blood were more than those in the wounds repaired with the scaffold encoding lower concentration of dragon's blood or the scaffold without dragon's blood.③Results of VEGF expression:VEGF had been increasing continuously in the different transplantation wounds and the control wound from 1 to 3 weeks after different scaffolds transplantation, however, they had decreased in the different transplantation wounds after epidermis had grafted for 2 weeks on surface of the scaffolds transplanted on wounds for 2 weeks (4 weeks) and were similar to those of the 3rd in the control wound. From 1 to 3 weeks, expressions of VEGF were the most in the wounds transplanted with the collagen - chitosan porous scaffold encoding higher concentration of dragon's blood and the least in the control wounds without scaffold.④Results of CD31 positive neo-forming micro-vessels:Neo-forming micro-vessels expressing CD31 had been increasing continuously in the different transplantation wounds and the control wound from 1 to 3 weeks after different scaffolds transplantation. Neo-forming micro-vessels expressing CD31 were the most in the wounds transplanted with the collagen-chitosan porous scaffold encoding higher concentration of dragon's blood and the least in the control wounds without scaffold on the 1st,2nd and 3rd week.⑤Results of a-SMA positive mature vessels:The expressions ofα-SMA positive mature vessels in the different transplantation wounds and the control wound at different time were similar to those of CD31 positive signals, whereas, a-SMA positive signals were fewer than CD31 positive signals.Conclusion①dragon's blood can promote angiogenesis of the collagen - chitosan artificial dermal scaffold during repair of full thickness burn wound, and the collagen-chitosan artificial dermal stent encoding dragon's blood has brilliant applied prospects in repairing full thickness burn wound.②The effective intension of promoting angiogenesis of dragon's blood is relative to the concentration of it, higher concentration of dragon's blood is more effective that lower concentration of it.