异体颗粒状脱细胞真皮基质与自体刃厚皮复合移植修复大鼠皮肤缺损创面效果观察

目的 观察异体颗粒状脱细胞真皮基质(PADM)与自体刃厚皮复合移植修复大鼠皮肤缺损创面的效果.方法 采用随机数字表法将12只SD大鼠分为实验组和对照组,每组6只.于2组大鼠背部制作全层皮肤缺损创面,实验组创面复合移植SD大鼠异体PADM(扩张比10:5)及厚度0.20 mm的自体刃厚皮,对照组创面仅移植厚度0.20 mm自体刃厚皮.术后2周起打开敷料观察大鼠创面愈合情况.术后2、3、4、6、8、12、20周计算2组创面移植皮片成活率、收缩率(或扩张率).术后20周取2组创周正常皮肤及创面皮肤标本,采用HE染色法观察胶原纤维束结构,测量胶原纤维束直径和间隙率;用天狼星红染色法观察Ⅰ、Ⅲ型胶原分布情况,测量Ⅰ、Ⅲ型胶原含量及其比值.对实验数据行独立样本t检验、Levene检验、t'检验.结果 (1)术后2周,实验组大鼠创面移植皮片成活率[(76.1±13.1)%]低于对照组[(94.5±1.3)%,t'=3.440,P=0.018].术后3周,实验组创面移植皮片收缩率[(34±8)%]明显大于对照组[(16±12)%,t=-3.211,P=0.009];术后8周,2组移植皮片扩张率接近一致.(2)HE染色和天狼星红染色显示,与大鼠创周正常皮肤比较,对照组移植皮片胶原纤维束呈均质化改变,胶原纤维纤细,排列紊乱;实验组移植皮片胶原纤维束结构、排列更接近创周正常皮肤,可见未完全降解的PADM.与对照组创面皮肤胶原纤维束直径[(7.3±1.4)μm]、间隙率[(17±4)%]、Ⅰ型胶原含量[(68.1±8.4)%]、Ⅲ型胶原含量[(32.0±8.4)%]以及Ⅰ、Ⅲ型胶原比例(2.3±1.0)比较,实验组胶原纤维束更粗[(9.6±0.8)μm,t=-3.562,P=0.005],间隙率更大[(24±5)%,t=-2.760,P=0.020],Ⅰ型胶原含量更高[(80.2±5.4)%,t=-2.981,P=0.014],Ⅲ型胶原含量更低[(19.8±5.4)%,t=2.981,P=0.014],Ⅰ、Ⅲ型胶原比例更高(4.3±1.2,t=-3.204,P=0.009).实验组创面皮肤上述胶原相关指标更接近于创周正常皮肤水平.结论 异体PADM在体内作为真皮再生模板,有助于改善自体刃厚皮所修复的大鼠皮肤缺损创面中真皮胶原纤维束的结构,提高再生真皮组织的成熟度.

Abstract：

Objective To evaluate the effects of mixed grafting of allogeneic PADM and autologous STS on wound healing of full-thickness defect in rats. Methods Full-thickness defects with size of 6 cm×4 cm were produced on the back of 12 SD rats, and they were divided into E group(n =6) and C group ( n = 6) according to the random number table. The wounds in E group were grafted with a mix of allogeneic PADM (expansion rate 10: 5) and autologous STS with thickness of 0.2 mm, while those in C group were grafted with autologous STS in the same thickness. The wound healing rate, survival rate, contraction rate,and expansion rate of transplanted skin were observed at post operation week (POW) 2, 3, 4, 6, 8, 12,20. Tissue samples form wounds and surrounding normal skin were harvested at POW 20 for histopathological observation as follows. The structure of collagen fiber bundle was observed by HE staining, the diameter and gap rate of collagen fiber bundle were also measured. The distribution of type Ⅰ and Ⅲ collagen was observed by sirsus red staining, and the contents of type Ⅰ , Ⅲ collagen and their ratio were also examined.Data were processed with independent samples t test, Levene test, and t' test. Results Survial rate of transplanted skin in E group at POW 2 [(76. 1 ± 13. 1)%] was obviously lower than that in C group [(94.5 ± 1.3)%, t' =3.440, P =0.018]. Contraction rate of transplanted skin in E, C groups at POW 3 showed significant difference [(34±8)%vs. (16 ±12)%, t = -3.211, P =0.009]. Compared with those in peri-wound normal skin, collagen fiber bundles in C group showed signs of homogenization, and collagen fibers were thin with irregular arrangement. Collagen fiber structure and arrangement of composite skin in E group were similar to those surrounding normal skin with incomplete degradation of PADM. Diameter of collagen fiber bundle [( 9.6 ± 0.8) μm] , gap rate between collagen bundle [( 24±5) %] , content of type Ⅰ collagen [( 80.2 ± 5.4) %] and the ratio of typeⅠto type Ⅲ collagen(4.3 ± 1.2) in E group were all increased as compared with those inC group [(7.3±1.4) μm (t = -3.562, P =0.005), (17±4)%( t =-2.760, P =0.020), (68.1 ±8.4)%(t = -2.981, P =0.014), 2.3±1.0(t = -3.204, P =0. 009)], while content of type Ⅲ collagen [( 19.8 ± 5.4) %] in E group was lower than that in C group [(32.0 ±8.4)% , t = 2. 981, P = 0. 014]. Above-mentioned indexes of collagen in wound of E group were similar to those of normal skin surrounding the wound. Conclusions Allogeneic PADM used as dermal regeneration template is beneficial in improving collagen fiber bundle structure in dermis layer of rats with fullthickness skin wounds when repaired with autologous STS, and it accelerates maturation of regenerative dermal tissue.

Effect of particulate allogeneic acellular dermal matrix(PADM) combined with autologous split-thickness skin (STS) on wound healing in rats

Objective To evaluate the effects of mixed grafting of allogeneic PADM and autologous STS on wound healing of full-thickness defect in rats. Methods Full-thickness defects with size of 6 cm×4 cm were produced on the back of 12 SD rats, and they were divided into E group(n =6) and C group ( n = 6) according to the random number table. The wounds in E group were grafted with a mix of allogeneic PADM (expansion rate 10: 5) and autologous STS with thickness of 0.2 mm, while those in C group were grafted with autologous STS in the same thickness. The wound healing rate, survival rate, contraction rate,and expansion rate of transplanted skin were observed at post operation week (POW) 2, 3, 4, 6, 8, 12,20. Tissue samples form wounds and surrounding normal skin were harvested at POW 20 for histopathological observation as follows. The structure of collagen fiber bundle was observed by HE staining, the diameter and gap rate of collagen fiber bundle were also measured. The distribution of type Ⅰ and Ⅲ collagen was observed by sirsus red staining, and the contents of type Ⅰ , Ⅲ collagen and their ratio were also examined.Data were processed with independent samples t test, Levene test, and t' test. Results Survial rate of transplanted skin in E group at POW 2 [(76. 1 ± 13. 1)%] was obviously lower than that in C group [(94.5 ± 1.3)%, t' =3.440, P =0.018]. Contraction rate of transplanted skin in E, C groups at POW 3 showed significant difference [(34±8)%vs. (16 ±12)%, t = -3.211, P =0.009]. Compared with those in peri-wound normal skin, collagen fiber bundles in C group showed signs of homogenization, and collagen fibers were thin with irregular arrangement. Collagen fiber structure and arrangement of composite skin in E group were similar to those surrounding normal skin with incomplete degradation of PADM. Diameter of collagen fiber bundle [( 9.6 ± 0.8) μm] , gap rate between collagen bundle [( 24±5) %] , content of type Ⅰ collagen [( 80.2 ± 5.4) %] and the ratio of typeⅠto type Ⅲ collagen(4.3 ± 1.2) in E group were all increased as compared with those inC group [(7.3±1.4) μm (t = -3.562, P =0.005), (17±4)%( t =-2.760, P =0.020), (68.1 ±8.4)%(t = -2.981, P =0.014), 2.3±1.0(t = -3.204, P =0. 009)], while content of type Ⅲ collagen [( 19.8 ± 5.4) %] in E group was lower than that in C group [(32.0 ±8.4)% , t = 2. 981, P = 0. 014]. Above-mentioned indexes of collagen in wound of E group were similar to those of normal skin surrounding the wound. Conclusions Allogeneic PADM used as dermal regeneration template is beneficial in improving collagen fiber bundle structure in dermis layer of rats with fullthickness skin wounds when repaired with autologous STS, and it accelerates maturation of regenerative dermal tissue.