丝素真皮组织支架应用对创面愈合过程中微血管形成的影响

Vascularisation of silk fibroin as dermal tissue scaffold in skin loss wound of rat

目的动态观察丝素真皮多孔支架于大鼠皮肤缺损创面应用后的血管化过程。方法以大鼠背部皮肤缺损为动物模型,将50只SD大鼠随机分为实验组和对照组,每组25只。实验组采用丝素多孔支架加自体薄皮复合移植的方法,修复真皮组织缺损创面,对照组以海绵加自体薄皮移植作为对照。分别于术后1周、2周、3周、4周和6周取材,HE染色观察创面组织学变化,免疫组化法分别检测标本中CD34和血管内皮生长因子(VEGF)的表达。结果光镜下观察两种材料植入后,1周后可见对照组炎症反应明显,实验组肉芽组织化较快。随着材料肉芽组织化,植入材料逐渐降解,以对照组较为明显。在第6周,可见丝素支架内完全充满组织,细胞数量减少,胶原排列呈编织状,形成组织相对成熟。而对照组部分区域未完全充满组织,细胞数量较多,形成组织相对幼稚,胶原排列有时呈现集束状。免疫组化显示:在术后1～4周,两组创面组织中CD34和VEGF表达逐渐升高,实验组VEGF在第3周达到高峰(15.8±3.7)%,CD34在第4周达到高峰(8.4±2.0)%,对照组二者表达高峰滞后。实验组CD34表达在第2、3、4周均高于对照组,两组比较差异有统计学意义(t值分别为0.031、0.022、0.039,P<0.05)。实验组VEGF表达在第2、3、4周均高于对照组,两组比较差异有统计学意义(t值分别为0.023、0.033、0.041,P<0.05)。结论丝素多孔真皮支架与自体薄皮复合移植后,早期可以促进VEGF和CD34表达,有利于组织血管化,后期促进组织成熟,加快组织重塑化过程。

Objective To investigate vascularisation of silk fibroins as dermal tissue scaffold in skin loss wound of rat. Methods The rat wounds of skin loss were divided into two groups for the study. The study group was covered by silk fibrin membrane with overlying thin split-thickness autograft, while the other received a sponge and split-thickness autograft as control. For each group, at the 1 st, 2nd, 3rd, 4th and 6th week post operation, 3 wound specimens were obtained and the vascular endothelial growth factor （VEGF） and CD34 expression were examined respectively by means of immunohistochemistry method. In addition, was observed the tissue with HE staining. Results HE staining demonstrated that granulation tissue in study group increased faster than in control group, and less inflammation in study group than in the control group. In the 6th week, the study group was full of new tissue and cell number reduced, but that was not found in the control. From 1 st to 4th week post operation, the expression of the VEGF and CD34 were increased gradually during wound healing. In study group, VEGF expression reached a peak at the 3rd week, and CD34 expression reached the peak at the 4th week. However, in control group, the expression of the VEGF and CD34 reached a peak at the 4th and 6th week respectively. The CD34 expression was higher in the study group at the 2nd, 3th and 4th week （4.1 ± 0.7, 7.8 ± 1.7, 8.4 ± 2.0） when compared with control group （2.1 ± 0.7, 5.4 ± 1.4, 6.1 ± 1.3 ）. VEGF expression was also higher in the study group at the 2nd, 3th and 4th week （8. 1 ±0.7, 15.8 ±3.7, 14. 1 ± 2. 1 ） when compared with control group （5.13 ± 0.7, 11.4 ± 3.4, 12.2 ± 2.3 ）. Conclusion The silk fibrin membrane could act as dermal tissue scaffold to induce the expression of VEGF and CD34, thus promote microvessel formation and improve the quality during would healing.