血竭负载人工真皮支架对猪Ⅲ°烧伤创面修复中VEGF表达及创面收缩的影响

Effects of dragon's blood encoded in collagen-chitosan artificial dermal stent on VEGF expression and wound contraction during repair of full-thickness burn wounds in pigs

目的探讨胶原-壳聚糖人工真皮支架负载不同浓度血竭对Ⅲ°烧伤创面修复中VEGF表达及创面收缩的影响。方法将负载两种不同浓度血竭(4 g/L和1 g/L)的真皮支架各移植于6头猪(分别为A组和B组)Ⅲ°烧伤清创后创面,对植入支架1、2、3周后的创面及植入支架2周创面加植表皮后2周的创面修复情况(4周创面)进行观察。同时通过采用免疫组织化学的方法,对不同时间的创面中细胞表达的VEGF及肌成纤维细胞表达的α-SMA进行检测和观察。实验以植入胶原-壳聚糖人工真皮支架及不植入支架的烧伤创面作为对照(分别为C组和D组)。结果①负载高浓度血竭的胶原-壳聚糖/硅橡胶双层人工真皮支架创面修复好于其他两种支架及不植入支架创面;②VEGF表达结果:四组1~3周VEGF阳性表达呈持续性升高,差异有显著性(P<0.05);A、B、C组支架植入2周并植表皮2周后(4周)创面,VEGF阳性表达明显降低,D组4周与3周相比无显著性差异;不同时间点,四组的阳性信号A组最多,D组最少;③创面α-SMA表达阳性的肌成纤维细胞数:A组表达高峰在2周,B、C、D组表达高峰在3周;各组不同时间点,D组表达最多,3~4周,A组表达最少。结论血竭能明显诱导胶原-壳聚糖人工真皮支架在修复Ⅲ°烧伤创面中的VEGF表达从而促进血管化速度,同时可抑制创面的收缩从而抑制瘢痕的增生,且血竭的这些作用与药物浓度有相关性,高浓度比低浓度的作用更为显著。

Objective To investigate the effects of collagen-chitosan artificial dermal stent encoding different concentrations of dragon＇s blood on VEGF expression and wound contraction during repair of full thickness burn wound. Method Wounds were observed in l, 2, and 3 weeks after the collagen-chitosan porous scaffolds encoding two different concentrations of dragon＇s blood（4 g/L and 1 g/L as group A and B） 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 （4 weeks）. At same time,VEGF expressions and myofibroblasts expressing ct-SMA in wounds of different time were detected in situ by immunohistochemical staining. The burn wounds repaired with collagen-chitosan porous scaffolds and without any scaffold transplantation were studied as the control （ as group C and D）. Findings （ 1 ） The wounds repaired with collagen - chitosan porous scaffold encoding higher concentration of dragon＇s blood was better than those repaired with the other two porous scaffolds and that repaired without any porous scaffolds. （2） Results of VEGF expression： VEGF had been increasing continuously in the wounds of group A, B, C and D from 1 to 3 weeks after different scaffolds transplantation. However, they had decreased in wounds of group A, B and C after epidermis had been grafted for 2 weeks on the surface of the scaffolds transplanted on wounds for 2 weeks （4 weeks） and were similar to those of the 3rd week in the wounds of the group D. From 1 to 3 weeks, expressions of VEGF were the most in the wounds of group A and the least in the wounds of group D. （3） Myofibroblasts expressing c^-SMA： The peak of myo-fibroblastc^-SMA expressions was on the 2nd week in the wounds of the group A and on 3rd week in the wounds of group B, C and D with collagen - sulfonated carboxymethyl chitosan porous scaffold transplantation and on the 3rd week in the wounds with the other two scaffolds transplantation and in the control wound without dermal stent. From 1 to 4 weeks, expressions of myo-fibroblasts expressingct-SMA were the most in the wounds of group D. From 3 to 4 weeks, expressions were the least in the wounds of group A. Conclusion Dragon＇s blood can induce VEGF expressions in the full thickness burn wounds repaired with collagen - chitosan artificial dermal scaffolds to promote angiogenesis. It can also prohibit the wound contraction to inhibit scar hypertroph. The effects of dragon＇s blood are relative to its concentration. Higher concentration of dragon＇s blood is more effective lower concentration of it.